Spicer

®

Drive Axles

Application Guidelines

DAAG2014

March 2014
2 DAAG2014 March 2014
DAAG2014 March 2014 3

Table of Contents

Table of Contents

Important Information About These Guidelines .................... 5

Drive Axle Application Guidelines

General Notes and Formulas..............................................6-7

City Delivery

Description and Definitions ................................................... 8

Single and Tandem Axles...................................................... 9

Construction/Agriculture

Description and Definitions ..................................................10

Single, Tandem and Tridem Axles ...................................11-12

Fire Service

Description and Definitions ..................................................13

Single and Tandem Axles.....................................................14

Heavy Haul

Description and Definitions ..................................................15

Tandem and Tridem Axles....................................................16

Intercity Coach

Description and Definitions ..................................................17

Single Axles.........................................................................18

Linehaul

Description and Definitions ..................................................19

Single and Tandem Axles.................................................... 20

Logging

Description and Definitions ................................................. 21

Tandem and Tridem Axles................................................... 22

Mining

Description and Definitions ................................................. 23

Single, Tandem and Tridem Axles ....................................... 24

Motorhome

Description and Definitions ................................................. 25

Single Axles........................................................................ 26

Oil Field

Description and Definitions ................................................. 27

Tandem and Tridem Axles................................................... 28

Refuse

Description and Definitions ................................................. 29

Single and Tandem Axles.................................................... 30

Rescue

Description and Definitions ................................................. 31

Single and Tandem Axles.................................................... 32

School Bus

Description and Definitions ................................................. 33

Single Axles........................................................................ 34

Yard Tractor

Description and Definitions ................................................. 35

Single and Tandem Axles.................................................... 36

13,500 lb. Housing Structural Ratings ................................. 37

15,500 lb. Housing Structural Ratings ................................. 38

17,000 lb. Housing Structural Ratings.................................. 39

19,000 lb. Housing Structural Ratings ................................. 40

20,000 lb. Housing Structural Ratings ..................................41

21,000 lb. Housing Structural Ratings ................................. 42

22,000 lb. Housing Structural Ratings................................. 43

23,000 lb. Housing Structural Ratings ................................. 44

25,000 lb. Housing Structural Ratings ................................. 45

26,000 lb. Housing Structural Ratings ................................. 46

30,000 lb. Housing Structural Ratings ................................. 47

34,000 lb. Housing Structural Ratings................................. 48

35,000 lb. Housing Structural Ratings ................................. 49

40,000 lb. Housing Structural Ratings ............................50-51

44,000 lb. Housing Structural Ratings................................. 52

46,000 lb. Housing Structural Ratings............................53-54

50,000 lb. Housing Structural Ratings ................................. 55

52,000 lb. Housing Structural Ratings ................................. 56

60,000 lb. Housing Structural Ratings ................................. 57

70,000 lb. Housing Structural Ratings ................................. 58

Tridem Load Ratings ........................................................59-60

Spicer® Drive Axle Model Identification..........................61-62

Spicer® Drive Axle Identification

Drive Axle Head Assembly .................................................. 63

Parts Identification ............................................................. 63

 Axle Housing ................................................................ 63

 Axle Shaft .................................................................... 63

 Ring Gear and Pinion .................................................... 64

Nomenclature - General

Tandem Axle Assembly....................................................... 65

Housing and Output Shaft Assembly................................... 66

Forward Axle Pinion Assembly (Tandem Axle) .................... 67

Rear Axle Pinion Assembly (Single Axle)............................. 67

Wheel Differential............................................................... 68

Power Divider ..................................................................... 69
4 DAAG2014 March 2014

Table of Contents

Spindle Nut Systems ............................................................. 70

Axle Shaft Flange to Hub ...................................................... 71

Power Divider Operation.................................................. 72-73

Wheel Differential Lock ................................................... 74-75

Dual Range Tandem Drive Axles

Description and Operation .................................................. 76

Gearing and Torque Distribution - Dual Range Gearing........ 76

Planetary Double Reduction Axles....................................... 77

Track, SLR, SMC .................................................................... 78

Super Single Tires / Offset Wheels ...................................... 79

Ratings Charts..................................................................80-83

Glossary............................................................................84-97
DAAG2014 March 2014 5

Introduction

Introduction

Important Information About These Guidelines

Purpose

The purpose of these Drive Application Guidelines is to provide 

original equipment manufacturer (OEM) builders of mediumand heavy-duty trucks with information about which Spicer®

drive axle products are approved by Dana Holding Corporation’s 

Commercial Vehicle Products (Dana CVP) for use in common 

vocational applications in the USA and Canada. 

Use of Guidelines

These Guidelines apply to on-, on-off, and off-highway axle 

applications and vocations in the USA and Canada. Vehicle 

applications that meet the specified vocation definitions and 

specified axle criteria are approved by Dana CVP for use within 

the applicable General Requirements and Recommendations 

without formal review by Dana CVP. Applications outside the 

specified vocations, duty cycles, ratings, and all off-road 

applications must be reviewed and approved on an individual 

basis by the Dana CVP Application Engineering Department. 

This review requirement also applies to the approval of drive 

axles with available options. 

Words or Terms in red letters and underlined are defined in the 

Glossary section.

Drive Warranties

Dana CVP’s warranties for drive axles are printed in the Spicer®

Warranty Guide (SWGR1). Applications and installations must 

either meet the requirements of these Guidelines or be approved 

by the Dana CVP Application Engineering Department. Failure to 

obtain applications approval of the use of Spicer® axles or their 

components in non-approved applications will void the Dana 

CVP warranty coverage. Modification of the vehicle or drive axle 

configuration, changes in the vocational use, or service outside 

the limits of these Guidelines will void the Dana CVP warranty 

coverage. 

Questions

For answers to questions concerning the Guidelines or to request 

a Drive Axle Approval Request Form for a use not covered by the 

Guidelines, contact one of the following:

Dana Sales and Service Office

1-877-777-5360

24 hours a day in the USA or Canada

Dana Holding Corporation

Commercial Vehicle Products

3939 Technology Drive

Maumee, OH 43537

Phone: 1-877-342-3000

Changes to Guidelines

These Guidelines are subject to change at any time, without 

prior notice, at the discretion of Dana CVP. For the most 

current revision to these Guidelines, visit the Dana website 

at www.dana.com. 

Effective Date: [March 2014]
6 DAAG2014 March 2014

Guidelines

Drive Axle Application Guidelines

General Notes:

1. Additional ratios may be available and would require individual 

application approval. 

2. Maximum allowable torsional driveline acceleration is 300 

rad./sec./sec. within the defined operating speed range of the 

engine manufacturer. When a manual transmission is used, a 

soft dampened clutch is recommended. 

3. Double reduction models offer added durability and gross 

weight capability in severe service applications where higher 

numeric ratios are required. 

4. Single vehicle retarders can be approved with all axle models, 

provided the product selected meets all the application 

requirements of the specified vocation. 

5. The use of dual retarders (engine, exhaust, transmission and/

or electromagnetic) is only approved with tandem drive axle

models with gross weight ratings of 46,000 lbs. or higher 

and the maximum allowable retardation is limited to 100% 

of the max. rated engine torque. For line haul or heavy haul 

applications, the maximum allowable retardation can be 

limited to 110% of the max. rated engine torque. 

6. All vehicles with electromagnetic retarders, such as Telma 

or Eaton’s Hydraulic Launch Assist (HLA), require individual 

application approval by the Dana CVP Application Engineering 

Department. 

7. For optimum axle shaft retention to the hub, .750 in. diameter 

studs or .625 in. diameter studs with tapered dowels are 

recommended for single axles with GAWR ratings of 23,000 

lbs. and above or tandem and tridem drive axles with GAWR

ratings of 46,000 lbs. and above. OEMs are responsible for 

axle shaft retention on all units not dressed by Dana. See 

page 71 for illustration. 

8. Localized sources of heat, such as engine exhaust, that may 

cause high axle operating temperatures or reduced seal life 

are to be avoided. Maximum intermittent drive axle surface 

temperatures measured at the input seal are not to exceed 

300° F for more than 30 minutes. Maximum continuous 

operating temperatures are not to exceed 250° F.

9. Dana CVP application approval is required for all vehicles with 

hybrid power systems. 

10. The following optional components are approved by this 

Guideline. All options may not be available on every axle 

model.

 a. Driver-Controlled Wheel Differential Lock

 b. Oil Pump

 c. Low Maintenance Wheel Ends (LMS®)

11. The use of NoSPIN® differentials in any drive axle will result 

in the exclusion of axle shafts from warranty consideration. 

Certain other carrier components may also be excluded from 

warranty consideration if their failure is deemed to be the 

result of NoSPIN® use. Depending on the axle loading, the 

NoSPIN® can cause all the torque to be directed to one axle 

shaft resulting in overload and potential failure. NoSPIN® is a 

registered trademark of Eaton Corporation. 

12. Drive axle application approval and allowable gross axle 

weight are based on the vehicle suspension selected. Dana 

CVP is not responsible for the durability of any attachments 

to the axle housing(s) unless produced by Dana Holding 

Corporation. In addition, Dana CVP is responsible for the 

integrity of the bracket attachment only if the bracket is 

installed by Dana or if the bracket is installed by the vehicle 

manufacturer following procedures approved by Dana 

through prior agreement. 

13. For certain suspension models, Dana may require the use of 

an increased housing wall thickness. Refer to the Housing 

Structural Rating Section of this Guideline or contact Dana 

CVP Application Engineering for specific requirements. 

14. Drive axles configured with single tires and outset wheels

that increase the track over the standard track width with 

dual tires require special considerations. Allowable gross 

axle weight ratings may have to be reduced from the 

nominal rating to compensate for the increase in housing 

stress created through the usage of single tires with outset 

wheels. Refer to the Housing Structural Rating Section of 

this Guideline for additional information regarding gross axle 

weight ratings based on increased track width due either 

to the usage of single tires and outset wheels or wide track 

housings. Outset wheels greater than 2.0 in. are not approved. 

All drive axles with single tires and outset wheels require a 

pre-set hub system (such as Dana’s LMS®

 or LMSiTM).

15. Oil pumps and/or Driver-Controlled Wheel Differential Lock(s)

are recommended for operations where vehicles operate in 

areas of poor traction. 

16. It is the responsibility of the vehicle manufacturer and/or 

the dealer to accurately convey all approved axle loading 

information to the body builder if the chassis is sold 

incomplete. It is also the responsibility of the final vehicle 

builder to insure the assigned tagged values for GAWR and 

GVW/GCW do not exceed those limits approved by this 

Guideline. Dana is not responsible for non-compliance 

to this request. 
DAAG2014 March 2014 7

Guidelines

Guidelines

17. Suspension capacity shall not exceed nominal drive axle 

capacity by more than 3,000 lbs. per axle with the exception 

of the S20-045B, DS404, D40-145, D40-155, D40-156 and 

S20-140 drive axle models. For the above exceptions, only a 

suspension capacity of 1,000 lbs. per axle over the nominal 

drive axle capacity is approved. 

18. For straight trucks, pusher and tag axles should be used to 

comply with the Federal Bridge Formula. 

19. Vehicle testing of any nature voids the warranty on Dana 

Spicer® drive axles. 

20. For specific warranty coverage, see Spicer® Warranty Guide 

(SWGR1).

21. For approval of Spicer® drive lines, Bendix brakes or other 

Spicer components contact Dana at 1-877-777-5360. 

Formulas:

1. In vehicles equipped with driving steerable axles, the wheel 

speed mismatch between the front and rear axle(s) is a 

concern. This mismatch is affected by the front and rear axle 

ratios as well as the tire revolution per mile (TRPM) and tire 

static loaded radius (SLR). Dana CVP Application Engineering 

requires this mismatch value not to exceed +1.5%. The % of 

mismatch is calculated below:

For high vehicle speed:

% mismatch = (Rear drive axle ratio x rear axle tire TRPM) - (front drive axle ratio x front axle tire TRPM)

Rear drive axle ratio x rear axle tire TRPM

For slow vehicle speed:

% mismatch = (Rear drive axle ratio x front axle tire SLR) - (front drive axle ratio x rear axle tire SLR)

Rear drive axle ratio x front axle tire SLR
8 DAAG2014 March 2014

City Delivery

Vocational Description

• Pickup and delivery service within cities and/or suburban areas

• 100% of operation on road surfaces of concrete, asphalt and maintained gravel

• Three (3) miles between start/stops (typical)

• 100% going/up to 40% load return (typical)

Typical Vehicle Types

Armored Truck General Freight Truck Pickup and Delivery Side Truck

Ambulance Livestock Hauler Postal Delivery Stake Truck

Auto Transport Truck Moving Van Refrigerated Truck Tanker Truck

Beverage Truck Municipal Truck Regional Haul Utility Truck

Flatbed Truck Newspaper Delivery Roll Back Auto Transporter Wrecker

Service Definitions (vocational description applies to all operations)

• Operation 1 Grades up to 8%

• Operation 2 Grades up to 12%

• Operation 3 Grades up to 20%

Housing Structural Ratings (see Table of Contents)
DAAG2014 March 2014 9

City Delivery

City Delivery

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

8% Grade

Operation 2

12% Grade

Operation 3

20% Grade

Fastest Slowest

S14-110 13,500 16,5 325 560 23,000 23,000 N/A 3.73 5.38

S14-130 13,500 15.7 300 660 25,000 25,000 N/A 3.73 5.38

S16-130 15,500 18.1 325 605 35,000 25,000 N/A 3.73 5.38

S17-140 17,000 19.7 300 860 46,000 40,000 N/A 3.58 5.57

17060S 17,000 19.7 300 860 60,000 50,000 45,000 3.08 5.57

S19-140 19,000 19.7 300 860 46,000 40,000 N/A 3.58 5.57

19060S 19,000 20.1 300 860 60,000 50,000 45,000 3.08 5.57

19055P 19,000 20.1 300 860 60,000 55,000 50,000 5.32 7.60

19055T 19,000 20.1 300 860 60,000 55,000 50,000 3.90/5.32 5.57/7.60

S20-140 20,000 19.7 300 860 46,000 40,000 N/A 3.58 5.57

S21-140 21,000 19.7 300 860 46,000 40,000 N/A 3.58 5.57

21060S 21,000 21.1 300 860 60,000 50,000 45,000 3.08 5.57

21065P 21,000 21.1 300 860 60,000 55,000 50,000 5.32 7.60

21065T 21,000 21.1 300 860 60,000 55,000 50,000 3.90/5.32 5.57/7.60

S21-170 21,000 21.1 405 1450 80,000 65,000 55,000 3.07 5.57

S21-170E 21,000 21.1 405 1450 80,000 65,000 55,000 3.07 5.57

S21-190 21,000 22.0 485 1650 100,000 85,000 70,000 3.07 5.57

S21-190E 21,000 22.0 485 1650 100,000 85,000 70,000 3.42 5.57

22060S 22,000 21.1 300 860 60,000 50,000 45,000 3.08 5.57

22065P 22,000 21.1 300 860 60,000 55,000 50,000 5.32 7.60

22065T 22,000 21.1 300 860 60,000 55,000 50,000 3.90/5.32 5.57/7.60

23060SH 23,000 19.8 300 860 60,000 50,000 45,000 3.08 5.57

23082T 23,000 22.0 405 1450 80,000 65,000 55,000 3.70/5.04 5.43/7.39

S23-170 23,000 22.0 405 1450 80,000 65,000 55,000 3.07 5.57

S23-170E 23,000 22.0 405 1450 80,000 65,000 55,000 3.07 5.57

S23-190 23,000 22.0 485 1650 100,000 85,000 70,000 3.07 5.57

S23-190 23,000 19.8 550 1850 80,000 70,000 60,000 3.07 4.30

S23-190E 23,000 22.0 485 1650 100,000 85,000 70,000 3.42 5.57

S25-170 25,000 22.0 405 1450 80,000 65,000 55,000 3.42 5.57

S25-170E 25,000 22.0 405 1450 80,000 65,000 55,000 3,42 5.57

26082T 26,000 22.0 405 1450 80,000 65,000 55,000 3.70/5.04 5.43/7.39

S26-190 26,000 22.0 485 1650 100,000 85,000 70,000 3.42 5.57

S26-190E 26,000 22.0 485 1650 100,000 85,000 70,000 3.42 5.57

EconoTrek 6x2

S21-170/

S20-045B 40,000 21.1 405 1450 80,000 65,000 55,000 3.07 5.57

S21-190/ 

S20-045B 40,000 22.0 485 1650 100,000 85,000 70,000 3.07 5.57

Tandem Axles

DS344 34,000 19.7 430 1550 90,000 90,000 80,000 3.08 5.57

DS404 40,000 21.1 485 1650 90,000 90,000 80,000 3.08 5.57 1, 2

D40-145 40,000 19.3 485 1650 80,000 80,000 60,000 3.23 3.91 1

D40-145 40,000 19.3 485 1550/1750 80,000 80,000 60,000 3.23 3.91 1

D40-145 39,000 19.8 485 1650 80,000 70,000 50,000 3.23 3.91 1

D40-145 38,000 20.2 455 1550 80,000 N/A N/A 3.23 3.91 1, 3

D40-155 40,000 19.8 485 1650 80,000 80,000 80,000 2.26 2.79 1, 2

D40-156 40,000 20.7 485 1650 90,000 85,000 80,000 2.79 3.91 1, 2

D40-156 40,000 20.7 550 1850 80,000 80,000 80,000 2.93 3.91 1

DS405 40,000 21.1 485 1650 90,000 90,000 80,000 3.08 5.57 2

DSH40 40,000 21.1 550 1850 90,000 90,000 80,000 3.08 4.88

D40-170 40,000 21.1 550 1850 140,000 120,000 100,000 3.07 5.38

D46-170 46,000 21.1 550 1850 140,000 120,000 100,000 3.07 5.38

D46-170H 46,000 21.1 550 1850 140,000 120,000 100,000 3.07 5.38

Note 1: Suspension restrictions may exist with the DS404, D40-145, D40-155 and D40-156. Please consult the Housing Structural Ratings Section for minimum 

housing box section requirements.

Note 2: When multiple torque engines are specified, a maximum engine torque of 1750 lb-ft can be approved if the higher engine torque is limited to direct and/or 

overdrive transmission gears.

Note 3: Operation 1 is limited to 6% Grade.
10 DAAG2014 March 2014

Construction/Agriculture

Vocational Description

• Movement of material to, from, and around a job site

• 90% of loaded operation on prepared road surfaces of concrete, asphalt, gravel, crushed rock or hard packed dirt and up to 10% of 

loaded operation into sandy or muddy work areas

• Liftable tag and pusher axles are often used to increase legal load capacity on highway

• Vehicles typically operate a high percentage of time off-highway making a large number of stops and starts

• Straight trucks as well as trucks with equipment trailers are considered construction vehicles. Tractor/semi-trailers and trucks pulling 

material trailers or dump body pups will be considered mining applications and should be reviewed based on guidelines established 

for that vocation

Typical Vehicle Types

Asphalt Truck End/Side Dump Truck Landscaping Truck Stake Body Truck

Block/Brick Truck Feed Lot Truck Milk Tanker Truck Snowplow/Snowblower

Bucket Truck Flatbed Truck Mixer Truck Tanker Truck

Concrete Pumper Grain Truck Roll-Off Container Truck Transit Mixer

Crane/Cherry Picker Hook Lift Truck Silage Truck Utility Truck

Service Definitions (vocational description applies to all operations)

• Operation 1 GVW/GCW-straight trucks and straight trucks with equipment trailers. Grades up to 12%. 

Housing Structural Ratings (see Table of Contents)
DAAG2014 March 2014 11

Construction/Agriculture

Construction/Agriculture

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

12% Grade

Fastest Slowest

S14-110 13,500 16.5 300 520 23,000 3.73 5.38

S14-130 13,500 15.7 300 660 25,000 3.73 5.38

S16-130 15,500 18.1 325 605 25,000 3.73 5.38

S17-140 17,000 19.7 300 860 29,000 3.58 5.57

17060S 17,000 19.7 300 860 29,000 3.58 5.57

S19-140 19,000 19.7 300 860 31,000 3.58 5.57

19060S 19,000 20.1 300 860 31,000 3.55 5.57

19055P 19,000 20.1 300 860 31,000 5.32 7.21

19055T 19,000 20.1 300 860 31,000 3.90/5.32 5.29/7.21

21060S 21,000 21.1 300 860 33,000 3.55 5.57

21065P 21,000 21.1 300 860 33,000 5.32 7.21

21065T 21,000 21.1 300 860 33,000 3.90/5.32 5.29/7.21

S21-170 21,000 21.1 350 1350 50,000 3.07 5.57

S21-170E 21,000 21.1 350 1350 50,000 3.07 5.57

S21-190 21,000 21.1 375 1450 60,000 3.07 5.57

S21-190E 21,000 21.1 375 1450 60,000 3.07 5.57

22060S 22,000 21.1 300 860 34,000 3.55 5.57

22065P 22,000 21.1 300 860 34,000 5.32 7.21

22065T 22,000 21.1 300 860 34,000 3.90/5.32 5.29/7.21

23060SH 23,000 19.8 300 860 34,000 3.55 5.57

23082T 23,000 22.0 310 1150 50,000 3.70/5.04 5.43/7.39

S23-170 23,000 22.0 350 1350 50,000 3.07 5.57

S23-170E 23,000 22.0 350 1350 50,000 3.07 5.57

S23-190 23,000 22.0 375 1450 60,000 3.07 5.57

S23-190E 23,000 22.0 375 1450 60,000 3.42 5.57

S23-590 23,000 22.0 375 1450 60,000 4.75 7.30

S25-170 25,000 22.0 350 1350 50,000 3.07 5.57

S25-170E 25,000 22.0 350 1350 50,000 3.07 5.57

26082T 26,000 22.0 310 1150 50,000 3.70/5.04 5.43/7.39

S26-190 26,000 22.0 375 1450 60,000 3.42 5.57

S26-190E 26,000 22.0 375 1450 60,000 3.42 5.57

S26-590 26,000 22.0 375 1450 60,000 4.75 6.65

S30-190 30,000 22.7 375 1450 60,000 3.42 5.57

S30-190E 30,000 22.7 375 1450 60,000 3.42 5.57

S30-590 30,000 22.7 375 1450 60,000 4.75 6.65

S35-590 35,000 22.7 375 1450 60,000 4.75 6.65
12 DAAG2014 March 2014

Construction/Agriculture

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Tandem Axles

HP Torque 

(lb-ft)

Operation 1

12% Grade

Fastest Slowest

DS405 40,000 21.1 375 1450 66,000 3.55 5.57

DSH40 40,000 21.1 485 1650 70,000 3.55 4.88

D40-170 40,000 21.1 625 2050 100,000 3.42 5.38

DSH44 44,000 21.1 485 1650 72,000 3.55 5.29

DT463-P 46,000 22.0 600 1850 100,000 3.70/5.04 4.88/6.64

D46-170 46,000 22.0 625 2050 100,000 3.42 5.38 1

D46-170H 46,000 22.0 625 2050 100,000 3.42 5.38

D46-590HP 46,000 22.0 625 2050 110,000 4.75 7.75

D50-170 50,000 22.0 625 2050 100,000 3.42 4.56

D52-190P 52,000 22.0 625 2050 110,000 3.42 5.57

D52-590P 52,000 22.0 625 2050 110,000 4.75 7.75

D60-190P 60,000 22.7 625 2050 110,000 3.42 4.56

D60-590P 60,000 22.7 625 2050 110,000 4.75 7.75

D70-590P 70,000 22.7 625 2050 110,000 4.75 7.75

Tridem Axles

T60-174P Note 2 19.7 485 1650 80,000 3.90 4.63 2

TDT583-P Note 2 20.1 600 1850 100,000 3.90/5.32 4.88/6.64 2

T69-170HP Note 2 20.8 625 2050 100,000 3.91 4.78 2

T78-190P Note 2 20.8 625 2050 110,000 3.91 4.78 2

T78-590P Note 2 20.8 625 2050 110,000 4.75 7.30 2

Note 1: Suspension restrictions may exist with the D46-170. Please consult the Housing Structural Ratings Section for minimum housing box section requirements. 

Note 2: Allowable tridem gross axle weight rating (GAWR) varies with axle ratio. Refer to the Tridem Load Ratings Section for information regarding permissible 

gross axle weight ratings, page 59.
DAAG2014 March 2014 13

Fire Service

Fire Service

Vocational Description

• Vehicles used to transport people and equipment for the purpose of extinguishing fires or ambulance service

• 90% of operation on prepared road surfaces of concrete, asphalt, gravel, crushed rock or hard packed dirt 

and up to 10% of loaded operation into sandy or muddy work areas

• Mileage is typically under 15,000 miles per year

• Typical vehicle routes are three (3) miles between start and stop

• Vehicle retarders (engine, exhaust, transmission or electromagnetic) are common

• High engine horsepower and automatic transmissions are typical

• Loaded 100% of the time

Typical Vehicle Types

Aerial Ladders Emerg Veh non-pumper Foam Tender Truck Tankers

Aerial Platforms Fire Truck Hazardous Material

Ambulances First Responder Truck Pumpers

Service Definitions (vocational description applies to all operations)

• Operation 1 GVW-straight trucks. Grades up to 20%. 

Housing Structural Ratings (see Table of Contents)
14 DAAG2014 March 2014

Fire Service

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

20% Grade

Fastest Slowest

S14-110 13,500 16.5 330 550 24,500 3.73 5.13

S14-130 13,500 15.7 300 660 26,500 3.73 5.13

S16-130 15,500 18.1 330 605 26,500 3.73 5.13

S17-140 17,000 19.7 300 860 27,000 3.58 5.57

17060S 17,000 19.7 330 950 27,000 3.25 5.57

S19-140 19,000 19.7 300 860 31,000 3.58 5.57

19060S 19,000 20.1 330 950 31,000 3.25 5.57

21060S 22,000 21.1 330 950 34,000 3.25 5.57

S21-170 22,000 21.1 450 1450 45,000 3.07 5.57

S21-170E 22,000 21.1 450 1450 45,000 3.07 5.57

S21-190 22,000 21.1 525 1650 45,000 3.07 6.14

S21-190E 22,000 21.1 525 1650 45,000 3.42 6.14

22060S 22,000 21.1 330 950 34,000 3.25 5.57

23060SH 23,000 19.8 330 950 34,000 3.25 5.57

S23-170 23,000 22.0 450 1450 45,000 3.07 5.57

S23-170E 23,000 22.0 450 1450 45,000 3.07 5.57

S23-190 24,000 22.0 525 1650 46,000 3.07 6.14

S23-190E 24,000 22.0 525 1650 46,000 3.42 6.14

S25-170 26,000 22.0 450 1450 48,000 3.07 5.57

S25-170E 26,000 22.0 450 1450 48,000 3.07 5.57

S26-190 27,000 22.0 525 1650 49,000 3.42 6.14

S26-190E 27,000 22.0 525 1650 49,000 3.42 6.14

S30-190 31,000 22.7 525 1650 53,000 3.42 6.14

S30-190E 31,000 22.7 525 1650 53,000 3.42 6.14

S30-590 31,000 22.7 525 1650 53,000 4.75 6.65

S35-590 35,000 22.7 525 1650 58,000 4.75 6.65

Tandem Axles

DS404 40,000 21.1 500 1550 62,000 3.25 5.57 1

DS405 42,000 21.1 500 1550 64,000 3.25 5.57

DSH40 42,000 21.1 550 1850 64,000 3.25 4.88

D40-170 42,000 21.1 625 2050 64,000 3.21 5.57

DSH44 45,000 21.1 550 1850 67,000 3.25 5.29

D46-170 46,000 22.0 625 2050 68,000 3.21 5.57 1

D46-170H 50,000 22.0 625 2050 70,000 3.21 5.57

D50-170 52,000 22.0 625 2050 72,000 3.21 5.57

D52-190P 54,000 22.0 625 2050 76,000 3.42 5.38

D60-190P 60,000 22.7 625 2050 82,000 3.42 5.38

Note 1: Suspension restrictions may exist with the DS404 and D46-170. Please consult the Housing Structural Ratings Section for minimum housing box

section requirements.
DAAG2014 March 2014 15

Heavy Haul

Heavy Haul

Vocational Description

• Movement of heavy equipment or materials at legal maximums or special permit loadings

• Exclusive operation on prepared road surfaces of concrete, asphalt, and maintained gravel

• High horsepower engines and auxiliary transmissions are typically used

• Loaded going and empty return

• Infrequent stops

Typical Vehicle Types

Flatbed Lowboy

Heavy Equipment Transport Specialized Heavy Haul

Heavy Wrecker Steel Hauling

Service Definitions (vocational description applies to all operations)

• Operation 1 Grades up to 8%

• Operation 2 Grades up to 12%

Housing Structural Ratings (see Table of Contents)
16 DAAG2014 March 2014

Heavy Haul

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GCW)

Gear Ratios Notes

Tandem Axles

HP Torque 

(lb-ft)

Operation 1

8% Grade

Operation 2

12% Grade

Fastest Slowest

DT463-P 46,000 22.0 625 2050 190,000 175,000 3.70/5.04 4.56/6.20

D46-170H 46,000 22.0 625 2050 200,000 185,000 3.42 4.56

D46-590HP 46,000 22.0 650 2250 240,000 225,000 4.75 7.30

D50-170 50,000 22.0 625 2050 200,000 185,000 3.42 4.56

D52-190P 52,000 22.0 650 2250 240,000 225,000 3.58 4.78

D52-590P 52,000 22.0 650 2250 240,000 225,000 4.75 7.30

D60-190P 60,000 22.7 650 2250 240,000 225,000 3.58 4.78

D60-590P 60,000 22.7 650 2250 240,000 225,000 4.75 7.30

D70-590P 70,000 22.7 650 2250 240,000 225,000 4.75 7.30

Tridem Axles

T60-174P Note 1 19.7 485 1650 180,000 160,000 3.90 4.63 1

TDT583-P Note 1 20.1 625 2050 190,000 175,000 3.90/5.32 4.56/6.21 1

T69-170HP Note 1 20.8 625 2050 200,000 185,000 3.91 4.78 1

T78-190P Note 1 20.8 650 2250 240,000 225,000 3.91 4.78 1

T78-590P Note 1 20.8 650 2250 240,000 225,000 4.75 7.30 1

Note 1: Allowable tridem gross axle weight rating (GAWR) varies with axle ratio. Refer to the Tridem Load Ratings Section for information regarding permissible gross 

axle weight ratings, page 59.
DAAG2014 March 2014 17

Intercity Coach

Intercity Coach

Vocational Description

• Transportation of people and, on occasion, light freight between cities and suburban areas

• Exclusive operation on well-maintained paved surfaces

• High mileage operation

• Typical vehicle routes exceed 30 miles between start and stop

• No towed load allowed

Typical Vehicle Types

Cross Country Coach

Tour Coach

Vehicle Configuration

6 x 2 straight coach with fixed tag or pusher axle

Service Definitions (vocational description applies to all operations)

• Operation 1 Grades up to 8%

Housing Structural Ratings (see Table of Contents)
18 DAAG2014 March 2014

Intercity Coach

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

8% Grade

Fastest Slowest

22060S 22,000 20.7 350 1050 45,000 3.36 4.78

23060SH 23,000 19.8 350 1050 45,000 3.36 4.78

S23-170 23,000 21.1 375 1450 55,000 3.42 4.78

S23-190 23,000 21.1 485 1650 55,000 3.42 4.78

S25-170 25,000 21.1 375 1450 55,000 3.42 4.78

S26-190 26,000 21.1 485 1650 55,000 3.42 4.78

EconoTrek 6x2

S21-170/ 

S20-045B 40,000 21.1 375 1450 55,000 3.42 4.78

S21-190/ 

S20-145B 40,000 21.1 485 1650 55,000 3.42 4.78
DAAG2014 March 2014 19

Linehaul

Linehaul

Vocational Description

• Long distance transport of various types of freight in high mileage operation (min. 60,000 miles/year)

• Exclusive operation on road surfaces of good to excellent concrete or asphalt 

• Vehicle routes are typically on limited access highways and exceed 30 miles between starts and stops

• Limited secondary road usage (5% max.)

• Maximum infrequent grades of up to 8%

• Majority of vehicles are 4x2, 6x2 (fixed tag or pusher) and 6x4 tractor/trailer combination and some straight trucks

Typical Vehicle Types

Auto Haulers General Freight Lumber Haulers Refuse/On-Hwy Trailer

Bulk Haulers Grain Haulers Moving Van Tanker Trailer

Double Trailers Hay Haulers Pipe Hauler Triple Trailers

Flatbed Trailers Livestock Haulers Refrigerated Freight Van Trailer

Service Definitions (vocational description applies to all operations)

• Operation 1 Grades up to 3%

• Operation 2 Grades up to 8%

Housing Structural Ratings (see Table of Contents)
20 DAAG2014 March 2014

Linehaul

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

3% Grade

Operation 2

8% Grade

Fastest Slowest

21060S 21,000 21.1 300 860 60,000 60,000 3.08 4.63

S21-170 21,000 21.1 405 1450 100,000 90,000 3.07 4.56

S21-170 21,000 19.8 485 1650 90,000 80,000 3.07 4.10 1

S21-190 21,000 22.0 485 1650 140,000 110,000 3.07 4.56

S21-190 21,000 20.1 550 1850 100,000 80,000 2.93 4.30

S21-190 21,000 19.6 455 1650 90,000 80,000 2.53 2.87 1

S21-190 20,000 19.3 415 1450/1650 N/A 105,000 2.53 2.87

S21-190 20,000 18.9 455 1550/1750 N/A 105,000 2.53 2.87

22060S 22,000 21.1 300 860 60,000 60,000 3.08 4.63

23060SH 23,000 19.8 300 860 60,000 60,000 3.08 4.63

S23-170 23,000 21.1 405 1450 100,000 90,000 3.07 4.56

S23-170 23,000 19.3 485 1650 90,000 80,000 3.07 4.10

S23-190 23,000 22.0 485 1650 140,000 110,000 3.07 4.56

S23-190 23,000 19.8 550 1850 100,000 80,000 2.93 4.30

S23-190 23,000 19.1 455 1650 90,000 80,000 2.53 2.87 1

S23-190 23,000 18.9 415 1450/1650 N/A 105,000 2.53 2.87

EconoTrek 6x2

S21-170/ 

S20-045B 40,000 21.1 405 1450 100,000 90,000 3.07 4.56

S21-170/ 

S20-045B 40,000 19.8 485 1650 90,000 80,000 3.07 4.10 1

S21-190/ 

S20-045B 40,000 22.0 485 1650 140,000 110,000 3.07 4.56

S21-190/ 

S20-045B 40,000 20.1 550 1850 100,000 80,000 2.93 4.30

S21-190/ 

S20-045B 40,000 19.6 455 1650 90,000 80,000 2.53 2.87 1

S21-190/ 

S20-045B 40,000 19.3 415 1450/1650 N/A 105,000 2.53 2.87

S23-170/ 

S20-045B 40,000 21.1 405 1450 100,000 90,000 3.07 4.56

S23-170/ 

S20-045B 40,000 19.8 485 1650 90,000 80,000 3.07 4.10 1

S23-190/ 

S20-045B 40,000 22.0 485 1650 140,000 110,000 3.07 4.56

S23-190/ 

S20-045B 40,000 20.1 550 1850 100,000 80,000 2.93 4.56

S23-190/ 

S20-045B 40,000 19.6 455 1650 90,000 80,000 2.53 2.87 1

S23-190/ 

S20-045B 40,000 19.3 415 1450/1650 N/A 105,000 2.53 2.87

Tandem Axles

DS344 34,000 19.7 430 1550 90,000 90,000 3.08 4.11

DS404 40,000 21.1 500 1650 143,000 110,000 3.08 4.11 1, 2

DS404 40,000 19.7 550 1850 80,000 80,000 3.08 4.11 2

DS404 40,000 18.9 455 1550/1750 80,000 80,000 2.64 2.93 2

D40-145 40,000 19.3 485 1650 110,000 80,000 3.23 3.91 1, 2

D40-145 39,000 19.8 485 1650 100,000 80,000 3.23 3.91 1, 2

D40-145 38,000 20.2 485 1650 90,000 80,000 3.23 3.91 1, 2, 3

D40-155 40,000 19.8 485 1650 80,000 80,000 2.26 2.79 1, 2

D40-156 40,000 21.1 500 1650 145,000 110,000 2.79 3.91 1, 2

D40-156 40,000 21.1 550 1850 80,000 80,000 2.93 3.91 2

DS405 40,000 21.1 500 1650 143,000 110,000 3.08 4.11 1

DS405 40,000 19.7 550 1850 80,000 80,000 3.08 4.11

DS405 40,000 18.9 455 1550/1750 80,000 80,000 2.64 2.93

DSH40 40,000 21.1 600 2050 143,000 110,000 3.08 4.88

D40-170 40,000 21.1 625 2050 185,000 160,000 3.07 4.10

D46-170 46,000 21.1 650 2250 185,000 160,000 3.07 4.10

D46-170H 46,000 21.1 650 2250 185,000 160,000 3.07 4.10

Note 1: When engines with multiple torque outputs are specified, a maximum engine torque of 1750 lb-ft can be approved if limited to direct and overdrive 

transmission gears only.

Note 2: Suspension restrictions may exist with the DS404, D40-145, D40-155 and D40-156. Please consult the Housing Structural Ratings Section for minimum 

housing box section requirements. 

Note 3: Operation 2 is limited to 6% maximum grade.
DAAG2014 March 2014 21

Logging

Logging

Vocational Description

• Movement of logs, chips and pulp between logging sites, mills or processing plants

• High horsepower engines and vehicle retarders are typically used

• Vehicle routes are typically 3 to 30 miles between starts and stops

• Fully loaded going and empty return

• Majority of vehicles are 6x4 tractor/trailer combination or trucks with full trailers unique to this vocation

Typical Vehicle Types

Chip Hauler Log Hauler Straight Truck with Trailer

Divorced Hauler Pole Truck & Trailer Tractors with Pole Trailers

Service Definitions (vocational description applies to all operations)

• Operation 1 Exclusive operation on road surfaces of concrete or asphalt. Grades not exceeding 8%.

• Operation 2 Infrequent grades up to 12%. 90% of loaded operation on prepared road surfaces of concrete, asphalt, gravel, 

crushed rock, or hard packed dirt with up to 10% of loaded operation into sandy or muddy job sites.

• Operation 3 Infrequent grades up to 20%. 90% of loaded operation on prepared road surfaces of concrete, asphalt, gravel, 

crushed rock, or hard packed dirt with up to 10% of loaded operation into sandy or muddy job sites.

Housing Structural Ratings (see Table of Contents)
22 DAAG2014 March 2014

Logging

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Tandem Axles

HP Torque 

(lb-ft)

Operation 1

8% Grade

Operation 2

12% Grade

Operation 3

20% Grade

Fastest Slowest

DS405 40,000 21.1 485 1650 80,000 N/A N/A 3.36 4.88

DSH40 40,000 21.1 550 1850 100,000 N/A N/A 3.36 4.33

D40-170 40,000 21.1 625 2050 160,000 150,000 135,000 3.42 4.78

DT463-P 46,000 22.0 600 1850 150,000 140,000 130,000 3.70/5.04 4.88/6.64

D46-170H 46,000 22.0 625 2050 160,000 150,000 135,000 3.42 4.78

D46-590HP 46,000 22.0 625 2050 180,000 170,000 160,000 4.75 7.30

D50-170 50,000 22.0 625 2050 160,000 150,000 135,000 3.42 4.78

D52-190P 52,000 22.0 625 2050 180,000 170,000 160,000 3.42 4.78

D52-590P 52,000 22.0 625 2050 180,000 170,000 160,000 4.75 7.30

D60-190P 60,000 22.7 625 2050 180,000 170,000 160,000 3.42 4.78

D60-590P 60,000 22.7 625 2050 180,000 170,000 160,000 4.75 7.30

D70-590P 70,000 22.7 625 2050 180,000 170,000 160,000 4.75 7.30

Tridem Axles

T60-174P Note 1 19.7 485 1650 120,000 110,000 100,000 3.90 4.63 1

TDT583-P Note 1 20.1 600 1850 150,000 140,000 130,000 3.90/5.32 4.88/6.64 1

T69-170HP Note 1 20.8 625 2050 160,000 150,000 135,000 3.91 4.78 1

T78-190P Note 1 20.8 625 2050 180,000 170,000 160,000 3.91 4.78 1

T78-590P Note 1 20.8 625 2050 180,000 170,000 160,000 4.75 7.30 1

Note 1: Allowable tridem gross axle weight rating (GAWR) varies with axle ratio. Refer to the Tridem Load Ratings Section for information regarding permissible gross 

axle weight ratings.
DAAG2014 March 2014 23

Mining

Mining

Vocational Description

• Movement of rock, ore, gravel and minerals around mine sites and between mines and processing plants

• High horsepower engines are typically used in this vocation

• Vehicle routes are typically 3 to 30 miles between starts and stops

• 90% of operation on road with up to 10% into sandy or muddy job sites

• Fully loaded going and empty return

• Tractor/trailer and straight truck/material trailer combinations are considered mining vehicles. Straight trucks without trailers 

or trucks with equipment trailers are considered construction applications and should be reviewed based on the guidelines 

established for that vocation. 

Typical Vehicle Types

Belly/Bottom Dump Trailer Michigan Special Gravel Trains Side/Semi-End Dump Trailer

Hopper Trailer Combinations Ore Hauling Trailer Super/Transfer Dump

Service Definitions (vocational description applies to all operations)

• Operation 1 Exclusive tractor/trailer or truck and material trailer operation on prepared road surfaces of concrete, asphalt, 

gravel, crushed stone, or hard packed dirt. Grades of up to 8%. 

• Operation 2 Tractor/trailer or truck and material trailer operation on prepared road surfaces of concrete, asphalt, gravel, 

crushed stone, or hard packed dirt with up to 10% of the total operation going into sandy or muddy mine sites. 

Grades of up to 20%. 

Housing Structural Ratings (see Table of Contents)
24 DAAG2014 March 2014

Mining

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

8% Grade

Operation 2

20% Grade

Fastest Slowest

S23-170 23,000 19.9 405 1450 65,000 N/A 3.90 4.56

S23-190 23,000 21.1 485 1650 80,000 N/A 3.73 4.56

Tandem Axles

DS405 40,000 21.1 485 1650 80,000 N/A 3.36 4.88

DSH40 40,000 21.1 550 1850 80,000 N/A 3.36 4.88

D40-170 40,000 21.1 625 2050 165,000 140,000 3.42 4.56

DT463-P 46,000 22.0 600 1850 165,000 130,000 3.70/5.04 4.88/6.64

D46-170H 46,000 22.0 625 2050 165,000 140,000 3.42 4.56

D46-590HP 46,000 22.0 625 2050 180,000 160,000 4.75 6.65

D50-170 50,000 22.0 625 2050 165,000 140,000 3.42 4.56

D52-190P 52,000 22.0 625 2050 180,000 160,000 3.42 4.78

D52-590P 52,000 22.0 625 2050 180,000 160,000 4.75 6.65

D60-190P 60,000 22.7 625 2050 180,000 160,000 3.42 4.78

D60-590P 60,000 22.7 625 2050 180,000 160,000 4.75 6.65

D70-590P 70,000 22.7 625 2050 180,000 170,000 4.75 6.65

Tridem Axles

T60-174P Note 1 19.7 485 1650 120,000 100,000 3.90 4.63 1

TDT583-P Note 1 20.1 600 1850 165,000 130,000 3.90/5.32 4.88/6.64 1

T69-170HP Note 1 20.8 625 2050 165,000 140,000 3.91 4.78 1

T78-190P Note 1 20.8 625 2050 180,000 160,000 3.91 4.78 1

T78-590P Note 1 20.8 625 2050 180,000 160,000 4.75 7.30 1

Note 1: Allowable tridem gross axle weight rating (GAWR) varies with axle ratio. Refer to the Tridem Load Ratings Section for information regarding permissible gross 

axle weight ratings.
DAAG2014 March 2014 25

Motorhome

Motorhome

Vocational Description

• Vehicles generally used for non-commercial transportation and as traveling domiciles for family

• Loaded full time

• May pull small passenger car, boat, or pickup truck

• Typical vehicle routes exceed 30 miles between starts and stops

• Annual mileage generally less than 30,000

• Typical operation is on paved roads and short distances within campgrounds and parks

• Equipped with automatic transmissions

Typical Vehicle Types

Integral Coach Recreational Vehicles

Vehicle Configurations

Straight coach type vehicles with towing ability:

4x2 straight coach

6x2 (with fixed tag or pusher axles)

Service Definitions (vocational description applies to all operations)

• Operation 1 Loaded full time. Infrequent grades up to 8%. 

Housing Structural Ratings (see Table of Contents)
26 DAAG2014 March 2014

Motorhome

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

8% Grade

Fastest Slowest

S14-110 13,500 16.5 300 605 27,500 4.10 5.38

S16-130 15,500 18.1 300 660 30,000 4.10 5.38

S17-140 17,000 19.7 300 860 40,000 3.58 5.57

17060S 17,000 19.7 300 860 40,000 3.55 5.57

S19-140 19,000 19.7 300 860 42,000 3.58 5.57

19060S 19,000 19.7 300 860 42,000 3.55 5.57

S20-140 20,000 19.7 300 860 42,000 3.58 5.57

S21-140 21,000 19.7 300 860 42,000 3.58 5.57

21060S 21,000 20.1 330 1050 44,000 3.55 5.57

S21-170 21,000 20.1 405 1550 50,000 3.58 5.57

S21-190 21,000 20.1 485 1750 65,000 3.58 5.57

22060S 22,000 20.1 330 1050 45,000 3.55 5.57

23060SH 23,000 19.6 330 1050 45,000 3.55 5.57

S23-170 23,000 20.1 405 1550 50,000 3.58 5.57

S23-190 23,000 20.1 485 1750 65,000 3.58 5.57

EconoTrek 6x2

S21-170/ 

S20-045B 40,000 20.1 405 1550 60,000 3.07 5.57

S21-190/ 

S40-145B 40,000 20.1 485 1750 70,000 3.07 5.57
DAAG2014 March 2014 27

Oil Field

Oil Field

Vocational Description

• Movement of production-related products, supplies and tools between job sites

• Movement of processing equipment and laboratories on job sites

• Low mileage operations on road surfaces made of concrete, asphalt, maintained gravel, crushed rock or hard packed dirt

• High horsepower engines common

• Vehicles are typically 6x4 or 6x6 straight trucks or tractors with permanently mounted equipment for well servicing or exploration

Typical Vehicle Types

Cementing Vehicle Fracturing Truck Tanker

Demolition Geophysical Exploration Well Serving Truck

Drill Rig Rigging Truck Winch Truck

Service Definitions (vocational description applies to all operations)

• Operation 1 Up to 25% job site operation, minimum 3 miles between stops, exclusive operation on prepared road surfaces. 

Grades up to 12%. 

• Operation 2 Full-time job site operation, frequent starts and stops, fully loaded going and empty return, low mileage. 

Grades up to 12%. 

Housing Structural Ratings (see Table of Contents)
28 DAAG2014 March 2014

Oil Field

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Tandem Axles

HP Torque 

(lb-ft)

Operation 1

12% Grade

Operation 2

12% Grade

Fastest Slowest

DS405 40,000 21.1 375 1450 100,000 N/A 3.55 5.29

DSH40 40,000 21.1 485 1650 100,000 N/A 3.55 4.88

D40-170 40,000 21.1 625 2050 120,000 100,000 3.42 5.38

DSH44 44,000 21.1 485 1650 72,000 72,000 3.55 5.29 3

DT463-P 46,000 22.0 600 1850 120,000 100,000 3.70/5.04 4.88/6.64

D46-170 46,000 22.0 625 2050 120,000 100,000 3.42 5.38 1

D46-170H 46,000 22.0 625 2050 120,000 100,000 3.42 5.38

D46-590HP 46,000 22.0 625 2050 140,000 120,000 4.75 6.65

D50-170 50,000 22.0 625 2050 120,000 100,000 3.42 5.38

D52-190P 52,000 22.0 625 2050 140,000 120,000 3.42 5.38

D52-590P 52,000 22.0 625 2050 140,000 120,000 4.75 6.65

D60-190P 60,000 22.7 625 2050 140,000 120,000 3.42 5.38

D60-590P 60,000 22.7 625 2050 140,000 120,000 4.75 6.65

D70-590P 70,000 22.7 625 2050 140,000 120,000 4.75 6.65

Tridem Axles

T60-174P Note 2 19.7 450 1650 100,000 80,000 3.90 4.63 2

TDT583-P Note 2 20.1 600 1850 120,000 100,000 3.90/5.32 4.88/6.64 2

T69-170HP Note 2 20.8 625 2050 120,000 100,000 3.91 4.78 2

T78-190P Note 2 20.8 625 2050 140,000 120,000 3.91 4.78 2

T78-590P Note 2 20.8 625 2050 140,000 120,000 4.75 7.30 2

Note 1: Suspension restrictions may exist with the D46-170. Please consult the Housing Structural Ratings Section for minimum housing box section requirements. 

Note 2: Allowable tridem gross axle weight rating (GAWR) varies with axle ratio. Refer to the Tridem Load Ratings Section for information regarding permissible 

gross axle weight ratings. 

Note 3: Applies to straight truck only, no combination vehicles.
DAAG2014 March 2014 29

Refuse

Refuse

Vocational Description

• 4x2 and 6x4 straight trucks, generally with automatic transmissions, used for residential refuse/recycle pickup

• Typically a high number of stops and starts per mile

• 6x4 straight trucks operating in commercial/industrial pickup with approximately 1 to 3 miles between stops

• 6x4 tractor/semi-trailers or 6x4 straight trucks with roll-off containers used for transfer/relocation of material. Stops are typically 

more than 10 miles apart

• 90% of loaded operation on road surfaces of concrete, asphalt or maintained gravel and up to 10% of loaded operation into landfill, 

transfer or recycling sites

Typical Vehicle Types

Front/Rear/Side Loading Residential/Commercial Pickup Scrap Truck Street Sweeper

Liquid Waste Hauler Roll-Off Container Truck Sewer/Septic/Vacuum Transfer Vehicle

Service Definitions (vocational description applies to all operations)

• Operation 1 GVW – Straight truck vehicles used for residential and commercial pickup of refuse and recyclables. 

Grades up to 20%. 

• Operation 2 GVW/GCW – Straight trucks with roll-off containers and tractor/semi-trailers used to transport material 

to transfer stations, recycling facilities, or landfill sites. Grades up to 8%. 

Housing Structural Ratings (see Table of Contents)
30 DAAG2014 March 2014

Refuse

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW/GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

20% Grade

Operation 2

8% Grade

Fastest Slowest

21060S 21,000 21.1 275 860 33,000 3.55 5.57 1

21065P 21,000 21.1 275 860 33,000 5.32 7.60 1

21065T 21,000 21.1 275 860 33,000 3.90/5.32 5.29/7.21 1

S21-170 21,000 21.1 310 1150 45,000 3.55 5.57

S21-190 21,000 22.0 375 1450 55,000 3.42 5.57

22060S 22,000 21.1 275 860 33,000 3.55 5.57 1

22065P 22,000 21.1 275 860 33,000 5.32 7.60 1

22065T 22,000 21.1 275 860 33,000 3.90/5.32 5.29/7.21 1

23060SH 23,000 20.2 275 860 33,000 3.55 5.57

23082T 23,000 22.0 310 1150 45,000 3.70/5.04 4.88/6.64

S23-170 23,000 22.0 310 1150 45,000 3.42 5.57

S23-170E 23,000 22.0 310 1150 45,000 3.42 5.57

S23-190 23,000 22.0 375 1450 55,000 3.42 5.57

S23-190E 23,000 22.0 375 1450 55,000 3.42 5.57

S23-590 23,000 22.0 375 1450 55,000 4.75 6.65

S25-170 25,000 22.0 310 1150 45,000 3.42 5.57

S25-170E 25,000 22.0 310 1150 45,000 3.42 5.57

26082T 26,000 22.0 310 1150 46,000 3.70/5.04 4.88/6.64

S26-190 26,000 22.0 375 1450 58,000 3.42 5.57

S26-190E 26,000 22.0 375 1450 58,000 3.42 5.57

S26-590 26,000 22.0 375 1450 58,000 4.75 6.65

S30-190 30,000 22.7 375 1450 58,000 3.42 5.57

S30-190E 30,000 22.7 375 1450 58,000 3.42 5.57

S30-590 30,000 22.7 375 1450 58,000 4.75 6.65

S35-590 35,000 22.7 375 1450 58,000 4.75 6.65

Tandem Axles

DS405 40,000 21.1 375 1450 N/A 110,000 3.36 5.57 2

DSH40 40,000 21.1 485 1650 N/A 110,000 3.36 4.88 2

D40-170 40,000 21.1 625 2050 60,000 165,000 3.42 5.57

DSH44 44,000 21.1 485 1650 64,000 N/A 3.36 5.29

DT463-P 46,000 22.0 600 1850 66,000 155,000 3.70/5.04 4.88/6.64

D46-170 46,000 22.0 625 2050 66,000 165,000 3.42 5.57 3

D46-170H 46,000 22.0 625 2050 66,000 165,000 3.42 5.57

D46-590HP 46,000 22.0 625 2050 66,000 175,000 4.75 6.65

D50-170 50,000 22.0 625 2050 70,000 165,000 3.42 5.57

D52-190P 52,000 22.0 625 2050 72,000 175,000 3.42 5.25

D52-590P 52,000 22.0 625 2050 72,000 175,000 4.75 6.65

D60-190P 60,000 22.7 625 2050 80,000 175,000 3.42 5.25

D60-590HP 60,000 22.7 625 2050 80,000 175,000 4.75 6.65

Note 1: The 21060S, 21065P, 21065T, 22060S, 22065P, and 22065T are not approved in vehicles equipped with retarders. 

Note 2: The DS405 and DSH40 are not approved for house-to-house pickup, residential refuse applications.

Note 3: Suspension restrictions may exist with the D46-170. Please consult the Housing Structural Ratings Section for minimum housing box section requirements.
DAAG2014 March 2014 31

Rescue

Rescue

Vocational Description

• Specialized all-wheel drive vehicles designed for rapid acceleration to airport crash sites

• Operation on road surfaces made of concrete, asphalt, maintained gravel, crushed rock, hard packed dirt, 

or other similar surfaces for 90% of the total miles and sandy or muddy crash sites for the remaining 10%

• Extremely low mileage operation

• High horsepower engines and automatic transmissions are typical

• Vehicle retarders are common (engine, transmission, electromagnetic)

Typical Vehicle Types

Airport Rescue Fire (ARF) Crash Fire Rescue (CFR) Emergency Service (EMT) Rapid Intervention Vehicle (RIV)

Vehicle Configuration

4x4 or 6x6 specialized straight trucks

Service Definitions (vocational description applies to all operations)

• Operation 1 100% loaded full time. Grades up to 20%.

Housing Structural Ratings (see Table of Contents)
32 DAAG2014 March 2014

Rescue

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

20% Grade

Fastest Slowest

S23-170 23,000 24.5 450 1450 45,000 3.07 5.57

S23-170E 23,000 24.5 450 1450 45,000 3.07 5.57

S23-190 24,000 24.5 525 1650 47,000 3.07 5.57

S23-190E 24,000 24.5 525 1650 47,000 3.42 5.57

S23-590 24,000 24.5 525 1650 47,000 4.75 6.65

S25-170 26,000 24.5 450 1450 50,000 3.07 5.57

S25-170E 26,000 24.5 450 1450 50,000 3.07 5.57

S26-190 27,000 24.5 525 1650 50,000 3.42 5.57

S26-190E 27,000 24.5 525 1650 50,000 3.42 5.57

S26-590 27,000 24.5 525 1650 50,000 4.75 6.65

S30-190 31,000 24.5 525 1650 54,000 3.42 5.57

S30-190E 31,000 24.5 525 1650 54,000 3.42 5.57

S30-590 31,000 24.5 525 1650 54,000 4.75 6.65

Tandem Axles

D46-170 46,000 24.5 700 2450 68,000 3.21 4.78 1

D46-170H 50,000 24.5 700 2450 70,000 3.21 4.78

D50-170 52,000 24.5 700 2450 72,000 3.21 4.78

D52-190P 54,000 24.5 700 2450 76,000 3.42 4.78

D52-590P 54,000 24.5 700 2450 76,000 4.75 6.65

D60-190P 60,000 24.5 700 2450 82,000 3.42 4.78

D60-590P 60,000 24.5 700 2450 82,000 4.75 6.65

Note 1: Suspension restrictions may exist with the D46-170. Please consult the Housing Structural Ratings Section for minimum housing box section requirements.
DAAG2014 March 2014 33

School Bus

School Bus

Vocational Description

• Transporting students to and from school and/or sponsored events

• Operation on prepared road surfaces of concrete, asphalt, maintained gravel, crushed rock, or hard packed dirt

• 2 stops per mile are considered typical

• Automatic transmissions are typical

• 100% load going / empty return (typical)

Typical Vehicle Types

Front Engine Commercial Chassis Front Engine Integral Coach Rear Engine Commercial Chassis

Rear Engine Integral Coach Shuttle Bus

Vehicle Configuration

4x2 straight bus

Service Definitions (vocational description applies to all operations)

• Operation 1 Grades up to 20%

Housing Structural Ratings (see Table of Contents)
34 DAAG2014 March 2014

School Bus

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GVW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

20% Grade

Fastest Slowest

S14-110 13,500 16.5 225 520 23,000 4.10 5.38

S16-130 15,500 16.5 275 605 25,000 4.10 5.38

S17-140 17,000 19.7 300 860 29,000 3.91 5.57

17060S 17,000 19.7 300 860 29,000 3.90 5.57

S19-140 19,800 19.7 300 860 31,000 3.91 5.57

19060S 19,800 20.1 300 860 31,000 3.90 5.57

S20-140 20,000 19.8 300 860 31,000 3.58 5.57

S21-140 21,000 19.8 300 860 31,000 3.58 5.57

21060S 21,000 20.1 300 860 33,000 3.90 5.57

S21-170 21,000 20.1 310 900 38,000 3.91 6.14

22060S 22,000 20.1 300 860 34,000 3.90 5.57

23060SH 23,000 19.3 300 860 34,000 3.90 5.57

S23-170 23,000 20.1 310 900 38,000 3.91 6.14
DAAG2014 March 2014 35

Yard Tractor

Yard Tractor

Vocational Description

• Transporting trailers on/off vessels, into/out of storage areas, around loading docks

• Operation on prepared road surfaces of concrete, asphalt or maintained gravel

• 6 stops per mile are considered typical

• Annual Mileage: very low

• Restricted Speed (< 25 mph)

Typical Vehicle Types

Port Tractor Rail Yard Spotter Trailer Spotter Yard Jockey

Vehicle Configuration

4x2 tractor 6x4 tractor

Service Definitions (vocational description applies to all operations)

• Operation 1 Grades up to 3%

Housing Structural Ratings (see Table of Contents)
36 DAAG2014 March 2014

Yard Tractor

Axle Model Max. GAWR

(lbs.)

Max. 

SLR (in.)

Engine Max. Gross Weight (lbs.) 

(GCW)

Gear Ratios Notes

Single Axles

HP Torque 

(lb-ft)

Operation 1

3% Grade

Fastest Slowest

S23-170 30,000 19.6 300 660 81,000 6.14 7.17 1

S23-190 30,000 19.6 325 660 100,000 6.14 7.17

S30-190 42,000 19.6 325 660 100,000 6.14 7.17

S30-590 42,000 19.6 325 660 100,000 7.30 9.97

Tandem Axles

DSH40 40,000 19.6 400 1550 125,000 5.57 6.50

D40-170 40,000 19.6 500 1650 160,000 6.14 7.17

DT463-P 46,000 19.6 500 1650 160,000 5.43/7.39 6.17/8.40

D46-170H 46,000 19.6 500 1650 160,000 6.14 7.17

D50-170 50,000 19.6 500 1650 160,000 6.14 7.17

D52-190P 52,000 19.6 500 1650 160,000 6.14 7.17

D60-190P 60,000 19.6 500 1650 160,000 6.14 7.17

Note 1: .50 in. housing wall thickness and 2.24 in. diameter axle shafts are required. 
DAAG2014 March 2014 37

Housing Structural Ratings

Housing Structural Ratings

13,500 lb. Housing Structural Ratings

Housing Dimensions (Standard Track Width)

Drive Axle Model

(Nominal GAWR

[See Note 1] - 13,500 lbs.)

Housing Box Section (in.)

(H x W x T)

Inner Bearing Shoulder to Inner 

Bearing Shoulder (in.)

Appoximate 

Track Width (in.)

Spindle 

Diameters

(Inner/Outer)

Notes

S14-110, S14-130 4.25 x 4.25 x .31

64.5-65.0 70

See Note 4 7

66.5-67.3 72

68.8-69.3 74

71.2 76

Gross Axle Ratings Based on the Use of Narrow or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

70 in. Maximum Track 

Width

74 in. Maximum Track 

Width

76 in. Maximum Track 

Width Notes

4.25 x 4.25 x .31 13,500 12,500 11,000 5, 6

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

70 in. Maximum Track 

Width

72 in. Maximum Track 

Width

74 in. Maximum Track 

Width

76 in. Maximum Track 

Width Notes

4.25 x 4.25 x .31 Not Approved Not Approved Not Approved Not Approved 2, 5, 6

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

70 in. Maximum Track 

Width

72 in. Maximum Track 

Width

74 in. Maximum Track 

Width

76 in. Maximum Track 

Width Notes

4.25 x 4.25 x .31 Not Approved Not Approved Not Approved Not Approved 2, 5, 6

 

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. The S14-110 and S14-130 are not approved with single outset wheels.

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Spindle dimensions vary with customer. 

 5. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in.

 6. Track widths are nominal and may vary with wheel equipment. 

 7. The S14-110 and S14-130 are not approved with suspension capacity ratings above 16,000 lbs.
Housing Structural Ratings

38 DAAG2014 March 2014

15,500 lb. Housing Structural Ratings

Housing Dimensions (Standard Track Width)

Drive Axle Model

(Nominal GAWR [See Note 1] - 15,500 

lbs.)

Housing Box Section (in.)

(H x W x T)

Inner Bearing Shoulder to Inner 

Bearing Shoulder (in.)

Appoximate 

Track Width (in.)

Spindle 

Diameters

(Inner/Outer)

Notes

S16-130 4.25 x 4.25 x .39

64.2-64.88 70

65.0-66.5 72 See Note 4 7

68.8-69.2 74

Gross Axle Ratings Based on the Use of Narrow or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

70 in. Maximum Track 

Width

74 in. Maximum Track 

Width Notes

4.25 x 4.25 x .39 15,500 14,500 5, 6

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

70 in. Maximum Track 

Width

71 in. Maximum Track 

Width

72 in. Maximum Track 

Width

74 in. Maximum Track 

Width Notes

4.25 x 4.25 x .39 Not Approved Not Approved Not Approved Not Approved 2, 5, 6

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

70 in. Maximum Track 

Width

72 in. Maximum Track 

Width

74 in. Maximum Track 

Width

76 in. Maximum Track 

Width Notes

4.25 x 4.25 x .39 Not Approved Not Approved Not Approved Not Approved 2, 5, 6

 

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. The S16-130 is not approved with single outset wheels.

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Spindle dimensions vary with customer. 

 5. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. 

 6. Track widths are nominal and may vary with wheel equipment. 

 7. The S16-130 is not approved with suspension capacity ratings above 17,000 lbs. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 39

17,000 lb. Housing Structural Ratings

Housing Dimensions (Standard Track Width)

Drive Axle Model

(Nominal GAWR [See Note 1] - 17,000 lbs.)

Housing Box Section (in.)

(H x W x T)

Spindle Diameters

(Inner/Outer) Spindle Type Notes

17060S, S17-140 5.24 x 4.61 x .38 3.250/2.625 L 4, 5

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T) 78 in. Maximum Track Width Notes

5.24 x 4.61 x .38 Not Available

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T) 75 in. Maximum Track Width Notes

5.24 x 4.61 x .38 Not Approved 2

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

72 in. Track 

(Standard Housing)

78 in. Track 

(Wide Track Housing)

75 in. Track 

(Outset Wheels)

5.24 x 4.61 x .38 Not Approved Not Approved Not Approved

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. The 17060S and S17-140 are not approved with single outset wheels.

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Track widths are nominal and may vary with wheel equipment. 

 5. The 17060S and S17-140 are not approved with suspension capacity ratings above 21,000 lbs. 
Housing Structural Ratings

40 DAAG2014 March 2014

19,000 lb. Housing Structural Ratings

Housing Dimensions (Standard Track Width)

Drive Axle Model

(Nominal GAWR [See Note 1] - 19,000 lbs.)

Housing Box Section (in.)

(H x W x T)

Spindle Diameters

(Inner/Outer) Spindle Type Notes

19060S, S19-140, 19055P, 19055T 5.24 x 4.61 x .38 3.250/2.625 L 4, 5

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T) 78 in. Maximum Track Width Notes

5.24 x 4.61 x .38 Not Available

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T) 75 in. Maximum Track Width Notes

5.24 x 4.61 x .38 Not Approved 2

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

72 in. Track 

(Standard Housing)

78 in. Track 

(Wide Track Housing)

75 in. Track 

(Outset Wheels)

5.24 x 4.61 x .38 Not Approved Not Available Not Approved

 

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. The 19060S, S19-140, 19055P and 19055T are not approved with single outset wheels.

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Track widths are nominal and may vary with wheel equipment. 

 5. The 19060S, S19-140, 19055P and 19055T are not approved with suspension capacity ratings above 21,000 lbs.
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 41

20,000 lb. Housing Structural Ratings

Housing Dimensions (Standard Track Width)

Drive Axle Model

(Nominal GAWR [See Note 1] - 20,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track SelecTTracTM

S20-045B, S20-140 5.24 x 4.61 x .38 5.24 x 4.61 x .38 3.250/2.625 R 6

Gross Axle Ratings Based on the Use of SelecTTracTM Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

75 in. Maximum Track Width

SelecTTracTM Notes

5.24 x 4.61 x .38 20,000 2, 5

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

75 in. Maximum Track Width

(Standard Track Housing)

78 in. Maximum Track Width

(SelecTTracTM Housing) Notes

5.24 x 4.61 x .38 17,000 17,000 2, 3, 5, 7

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 4)

Housing Box Section (in.)

(H x W x T)

73 in. Track

(Standard Housing)

75 in. Track

(SelecTTracTM Housing)

75 in. Track

(Standard w/Outset)

78 in. Track

(Select w/Outset) Notes

5.24 x 4.61 x .38 Not Approved Not Approved Not Approved Not Approved 2, 3, 5

 

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. The S20-140 are not approved with single tires and outset wheels.

 4. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 5. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 40 in. and a maximum track width of 75 in. for the S20-045B and 

78 in. for the S20-045BS axle models. 

 6. The S20-045B and S20-140 are not approved with suspension capacity ratings above 21,000 lbs. 

 7. Single tires with outset wheels beyond 2.0 in. are not approved. 
Housing Structural Ratings

42 DAAG2014 March 2014

21,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR

[See Note 1] - 21,000 lbs.)

Housing Box Section (in.) (H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track SelecTTracTM Wide Track

21060S, S21-060B, S21-140 5.24 x 4.61 x .43 5.24 x 4.61 x .43 5.24 x 4.61 x .50

3.750/3.250 R

7, 8, 9

21065P, 21065T 5.24 x 4.61 x .38 Not Available 5.24 x 4.61 x .56

S21-170, S21-190 5.24 x 4.61 x .43 5.24 x 4.61 x .43 5.24 x 4.61 x .63 7, 8

Gross Axle Ratings Based on the Use of SelecTTracTM or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .43 20,000 Not Available 2, 7, 8

5.24 x 4.61 x .50 Not Available 19,000 2, 9

5.24 x 4.61 x .56 Not Available 21,000 2

5.24 x 4.61 x .63 Not Available 21,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .38 Not Approved Not Available Not Available 2, 3

5.24 x 4.61 x .43 19,500 18,000 Not Available 2, 5, 6, 7, 8

5.24 x 4.61 x .50 Not Available Not Available 17,000 2, 5, 9

5.24 x 4.61 x .56 Not Available Not Available 19,000 2, 5

5.24 x 4.61 x .63 Not Available Not Available 21,000 2, 5

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 4)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Track Housing)

76 in. Track

(SelecTTracTM Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .38 26,000 Not Available Not Available 2, 4

5.24 x 4.61 x .43 29,000 26,000 Not Available 2, 4, 7, 8

5.24 x 4.61 x .50 Not Available Not Available 26,000 2, 4, 7, 9

5.24 x 4.61 x .56 Not Available Not Available 29,000 2, 4

5.24 x 4.61 x .63 Not Available Not Available 31,000 2, 4

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

79 in. Track

(Select w/Outset)

82 in. Track

(Wide w/Outset) Notes

5.24 x 4.61 x .38 Not Approved Not Available Not Available 3

5.24 x 4.61 x .43 29,000 23,000 Not Available 2, 4, 5, 7, 8

5.24 x 4.61 x .50 Not Available Not Available 23,000 2, 4, 5, 9

5.24 x 4.61 x .56 Not Available Not Available 24,000 2, 4

5.24 x 4.61 x .63 Not Available Not Available 26,000 2, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. The 21065P and 21065T are not approved with single tires and outset wheels.

 4. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 5. Single tires with outset wheels beyond 2.0 in. are not approved. 

 6. Single tires with outset wheels are approved for the S21-060B tag axle in a 6x2 configuration only. 

 7. SelecTTracTM is only available in S21-140, S21-170 and S21-190. 

 8. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 40 in. for SelecTTracTM.

 9. S21-140 is not available with wide track housings. 

 10. All 21,000-pound-rated, drive axle models are not approved with suspension capacity ratings above 23,000 lbs. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 43

22,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 22,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track Wide Track

22060S 5.24 x 4.61 x .43 5.24 x 4.61 x .50

3.750/3.250 R

2

22065P, 22065T 5.24 x 4.61 x .38 5.24 x 4.61 x .56 2

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .50 Not Available 19,000 2

5.24 x 4.61 x .56 Not Available 19,800 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .38 Not Approved Not Available Not Available 3

5.24 x 4.61 x .43 Not Approved Not Available Not Available 3

5.24 x 4.61 x .50 Not Available Not Available Not Approved 3

5.24 x 4.61 x .56 Not Available Not Available Not Approved 3

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 4)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

76 in. Track

(SelecTTracTM Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .38 26,000 Not Available Not Available 2, 4

5.24 x 4.61 x .43 29,000 Not Available Not Available 2, 4

5.24 x 4.61 x .50 Not Available Not Available 23,000 2, 4

5.24 x 4.61 x .56 Not Available Not Available 23,000 2, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. The 22060S, 22065P and 22065T are not approved with single outset wheels.

 4. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 5. All drive axle models are not approved with suspension capacity ratings above 23,000 lbs. 
Housing Structural Ratings

44 DAAG2014 March 2014

23,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR

[See Note 1] - 23,000 lbs.)

Housing Box Section (in.) (H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track SelecTTracTM Wide Track

S23-170 5.24 x 4.61 x .43 5.24 x 4.61 x .43 5.24 x 4.61 x .63

3.750/3.250 R

2, 5

23082T 5.24 x 4.61 x .56 Not Available 5.24 x 4.61 x .56 2

23060SH, S23-190, S23-590, S23-070B 5.24 x 4.61 x .50 5.24 x 4.61 x .50 5.24 x 4.61 x .63 2, 5, 7

S23-170H, S23-190H 5.24 x 4.61 x .63 Not Available 5.24 x 4.61 x .63 2

Gross Axle Ratings Based on the Use of SelecTTracTM or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .43 20,000 Not Available 2, 5

5.24 x 4.61 x .50 22,000 Not Available 2, 5, 7

5.24 x 4.61 x .56 Not Available 22,000 2

5.24 x 4.61 x .63 Not Available 23,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .43 20,000 18,000 Not Available 2, 4, 5

5.24 x 4.61 x .50 22,000 20,000 Not Available 2, 4, 5, 7

5.24 x 4.61 x .56 23,000 Not Available 19,000 2, 4

5.24 x 4.61 x .63 23,000 Not Available 21,000 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Track Housing)

76 in. Track

(SelecTTracTM Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .43 29,000 26,000 Not Available 2, 3, 5

5.24 x 4.61 x .50 30,000 29,000 Not Available 2, 3, 5, 7

5.24 x 4.61 x .56 32,000 Not Available 29,000 2, 3

5.24 x 4.61 x .63 32,500 Not Available 31,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

79 in. Track

(Select w/Outset)

82 in. Track

(Wide w/Outset) Notes

5.24 x 4.61 x .43 26,000 23,000 Not Available 2, 3, 4, 5

5.24 x 4.61 x .50 28,000 26,000 Not Available 2, 3, 4, 5, 7

5.24 x 4.61 x .56 30,000 Not Available 24,000 2, 3, 4

5.24 x 4.61 x .63 31,000 Not Available 26,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 40 in. for SelecTTracTM. 

 6. The .43 in. wall thickness housings are not approved with suspension capacity ratings above 24,000 lbs. 

The .50 in. wall thickness housings are not approved with suspension capacities rated above 26,000 lbs. 

The .63 in. wall thickness housings are not approved with suspension capacities above 29,000 lbs. 

 7. The 23060SH is not available in SelecTTracTM or wide track housings. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 45

25,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR

[See Note 1] - 25,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Standard Track SelecTTracTM Wide Track

S25-170 5.24 x 4.61 x .50 5.24 x 4.61 x .50 5.24 x 4.61 x .63 3.750/3.250 R 2, 5

Gross Axle Ratings Based on the Use of SelecTTracTM or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .50 22,000 Not Available 2, 5

5.24 x 4.61 x .63 Not Available 24,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 22,000 20,000 Not Available 2, 4, 5

5.24 x 4.61 x .63 Not Available Not Available 21,000 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Track Housing)

76 in. Track

(SelecTTracTM Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 30,000 29,000 Not Available 2, 3, 5

5.24 x 4.61 x .63 Not Available Not Available 31,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

79 in. Track

(Select w/Outset)

82 in. Track

(Wide w/Outset) Notes

5.24 x 4.61 x .50 28,000 26,000 Not Available 2, 3, 4, 5

5.24 x 4.61 x .63 Not Available Not Available 26,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 40 in. for SelecTTracTM. 

 6. The .50 in. wall thickness housings are not approved with suspension capacities rated above 26,000 lbs. 

The .63 in. wall thickness housings are not approved with suspension capacities above 29,000 lbs. 
Housing Structural Ratings

46 DAAG2014 March 2014

26,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 26,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track Wide Track

26082T 5.24 x 4.61 x .56 5.24 x 4.61 x .56

3.750/3.250 R 2

S26-190, S26-590 5.24 x 4.61 x .63 5.24 x 4.61 x .63

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .56 Not Available 22,000 2

5.24 x 4.61 x .63 Not Available 24,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .56 24,000 Not Available 19,000 2, 4

5.24 x 4.61 x .63 26,000 Not Available 21,000 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

76 in. Track

(Standard 

w/Outset)

76 in. Track

(SelecTTracTM

Housing)

78.5 in. Track

(Wide Track 

Housing)

82 in. Track

(Wide w/Outset) Notes

5.24 x 4.61 x .50 32,000 30,000 Not Available 29,000 25,000 2, 3, 4

5.24 x 4.61 x .63 32,000 31,000 Not Available 31,000 27,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. The .56 in. wall thickness housings are not approved with suspension capacities rated above 29,000 lbs. 

The .63 in. wall thickness housings are not approved with suspension capacities above 29,000 lbs. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 47

30,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 30,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Narrow/Standard/Wide Track

S30-190, S30-590 5.91 x 5.31 x .63 4.125/3.500 W 2

Gross Axle Ratings Based on the Use of Narrow or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

72.5 in. Maximum Track Width

Narrow Track

76 in. Maximum Track Width

Wide Track Notes

5.91 x 5.31 x .63 30,000 29,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Narrow Track Housing)

78 in. Maximum Track

(Standard Track Housing)

80 in. Maximum Track

(Wide Track Housing) Notes

5.91 x 5.31 x .63 28,000 26,000 24,000 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

72 in. Track 

(Narrow Housing)

74 in. Track

(Standard Housing)

76 in. Track

(Wide Track Housing) Notes

5.91 x 5.31 x .63 36,000 35,000 34,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Narrow w/Outset)

78 in. Track

(Standard w/Outset)

80 in. Track

(Wide w/Outset) Notes

5.91 x 5.31 x .63 34,000 32,000 31,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 74 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 
Housing Structural Ratings

48 DAAG2014 March 2014

34,000 lb. Housing Structural Ratings

Housing Dimensions (Standard Track Width)

Drive Axle Model

(Nominal GAWR [See Note 1] - 34,000 lbs.)

Housing Box Section (in.)

(H x W x T)

Spindle Diameters

(Inner/Outer) Spindle Type Notes

DS344 5.24 x 4.61 x .38 3.250/2.625 L 2

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.) 76 in. Maximum Track Width Notes

5.24 x 4.61 x .38 Not Available N/A

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.) 75 in. Maximum Track Width Notes

5.24 x 4.61 x .38 Not Approved 2, 3

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 4)

Housing Box Section (in.)

(H x W x T)

72 in. Track 

(Standard Housing)

75 in. Track 

(Wide Track Housing)

76 in. Track 

(Outset Wheels) Notes

5.24 x 4.61 x .38 Not Approved Not Available Not Approved 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. The DS344 is not approved with single outset wheels.

 4. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 5. All drive axle models are not approved with suspension capacity ratings above 40,000 lbs. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 49

35,000 lb. Housing Structural Ratings – Cast Steel Housing

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 35,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track Wide Track

S35-590 6.75 x 5.63 x .88 6.75 x 5.63 x .88 4.125/3.500 W 2

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

75 in. Maximum Track Width

Intermediate Track

80 in. Maximum Track Width

Wide Track

85 in. Maximum Track Width

Wide-Wide Track Notes

6.75 x 5.63 x .88 35,000 35,000 35,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(Intermediate Housing)

84 in. Maximum Track

(Wide Track Housing)

89 in. Maximum Track

(Wide-Wide Housing) Notes

6.75 x 5.63 x .88 Not Approved Not Approved Not Approved Not Approved 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

72 in. Track 

(Standard Track)

75 in. Track

(Intermediate Track)

80 in. Track

(Wide Track)

85 in. Track

(Wide-Wide Track) Notes

6.75 x 5.63 x .88 40,000 40,000 40,000 40,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard w/Outset)

79 in. Maximum Track 

(Intermediate w/Outset)

84 in. Maximum Track 

(Wide w/Outset)

89 in. Maximum Track 

(Wide-Wide w/Outset) Notes

6.75 x 5.63 x .88 Not Approved Not Approved Not Approved Not Approved 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. S35-590 is not approved with single outset wheels. 

 5. Dowel pins are not available on this housing. 
Housing Structural Ratings

50 DAAG2014 March 2014

40,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 40,000 lbs.)

Housing Box Section (in.) (H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Standard Track SelecTTracTM Wide Track

D40-145, D40-155, D40-156 5.24 x 4.61 x .38 5.24 x 4.61 x .38 Not Available

3.750/3.250 R

2, 4

DS404, DST40 5.24 x 4.61 x .38 Not Available 5.24 x 4.61 x .50 2, 6

D40-145H, D40-155H, D40-156H 5.24 x 4.61 x .43 5.24 x 4.61 x .43 Not Available 2, 4

DS405, DST41, DSH40 5.24 x 4.61 x .43 Not Available 5.24 x 4.61 x .50 2, 6

D40-170 5.24 x 4.61 x .43 5.24 x 4.61 x .43 5.24 x 4.61 x .63 2, 4

EconoTrekTM S21-170/S20-045B 5.24 x 4.61 x .43/.38 5.24 x 4.61 x .43/.38 Not Available 2, 4

EconoTrekTM S21-190/S20-045B 5.24 x 4.61 x .43/38 5.24 x 4.61 x .43/.38 Not Available 2, 4

Gross Axle Ratings Based on the Use of SelecTTracTM or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .38 40,000 Not Available 2, 4

5.24 x 4.61 x .43 40,000 Not Available 2, 4

5.24 x 4.61 x .50 Not Available 39,000 2, 6

5.24 x 4.61 x .63 Not Available 40,000 2

5.24 x 4.61 x .43/.38 40,000 Not Available 2, 4

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

75 in. Maximum Track 

(Standard Track Housing)

78 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .38 34,000 34,000 Not Available 2, 4, 5, 8

5.24 x 4.61 x .43 40,000 37,500 Not Available 2, 4, 5, 8

5.24 x 4.61 x .50 Not Available Not Available 35,000 2, 5, 6, 8

5.24 x 4.61 x .63 Not Available Not Available 40,000 2, 5, 8

5.24 x 4.61 x .43/.38 34,000 34,000 Not Available 2, 4, 5, 8

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

76 in. Track

(SelecTTracTM Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .38 54,000 54,000 Not Available 2, 3, 4

5.24 x 4.61 x .43 58,000 58,000 Not Available 2, 3, 4

5.24 x 4.61 x .50 Not Available Not Available 53,000 2, 3, 6

5.24 x 4.61 x .63 Not Available Not Available 62,000 2, 3

5.24 x 4.61 x .43/.38 54,000 54,000 Not Available 2, 3, 4

Housing Box Section (in.)

(H x W x T)

75 in. Track 

(Standard w/Outset)

78 in. Track 

(Select w/Outset)

82 in. Track 

(Wide w/Outset) Notes

5.24 x 4.61 x .38 40,000 40,000 Not Available 2, 3, 4, 5

5.24 x 4.61 x .43 48,000 44,000 Not Available 2, 3, 4, 5

5.24 x 4.61 x .50 Not Available Not Available 43,000 2, 3, 5, 6

5.24 x 4.61 x .63 Not Available Not Available 52,000 2, 3, 5

5.24 x 4.61 x .43/.38 40,000 40,000 Not Available 2, 3, 4, 5
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 51

40,000 lb. Housing Structural Ratings (cont'd.)

Housing Wall Thickness Requirements for Various Non-Proprietary Suspensions (See Note 7)

Suspension Minimum Box Section Requirements (in.)

(H x W x T)

Manufacturer Model Type Application USA Canada

Chalmers 800-40 Rubber Spring walking beam Vocational 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson HAS 40LH Trailing Arm Air Ride Linehaul 5.24 x 4.61 x .38 5.24 x 4.61 x .38

Hendrickson HAS 400 Trailing Arm Air Ride On-off highway 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson HAS 402 Trailing Arm Air Ride On-off highway 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson HMX 400 Rubber Spring walking beam Vocational 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson HN 402 Rubber Spring walking beam Vocational 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson HTB LT Air Ride On-highway 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson Primaax Trailing Arm Air Ride On-off highway 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson RS 403 Rubber Spring walking beam Vocational 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson R 403 Solid walking beam Vocational 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Hendrickson RT(E) 403 Steel Spring walking beam Vocational 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Neway ARDAB-240-5 Air Beam On-highway 5.24 x 4.61 x .38 5.24 x 4.61 x .38

Reyco 240AR Trailing Arm Air Ride On-highway 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Reyco 102AR Trailing Arm Air Ride On-highway 5.24 x 4.61 x .43 5.24 x 4.61 x .43

Reyco 102W 4 spring On-highway 5.24 x 4.61 x .38 5.24 x 4.61 x .38

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 40 in. for SelecTTracTM housings.

 5. Single tires with outset wheels beyond 2.0 in. are not approved. 

 6. The only wider track version of the DST40/41 is 78.5 in. The forward-rear housing has a .50 in. wall thickness while the rear-rear housing 

is .56 in. thick. 

 7. A minimum wall thickness of .433 in. (11 mm) is required when a suspension rated at 46,000 lbs. is used.

 8. For detailed track versus allowable gross axle weight rating information when outset wheels are used, see 40,000 lb. Tandem Rating Chart, page 80. 

 9. The .38 in. wall thickness housings are not approved with suspension capacity ratings above 42,000 lbs. 

The .43 in. wall thickness housings are not approved with suspension capacity ratings above 46,000 lbs. 
Housing Structural Ratings

52 DAAG2014 March 2014

44,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 44,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Standard Track Intermediate Track Wide Track

DSH44 5.24 x 4.61 x .50 5.24 x 4.61 x .50 5.24 x 4.61 x .50 3.750/3.250 R 2

Gross Axle Ratings Based on the Use of Intermediate or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

Intermediate Track

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .50 43,000 39,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(Inter Track Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 43,000 38,000 35,000 2, 4, 5

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

76 in. Track

(Intermediate Track Housing)

78.5 in. Track

Wide Track Housing Notes

5.24 x 4.61 x .50 62,000 58,000 53,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

79 in. Track 

(Intermediate w/Outset)

82 in. Track 

Wide w/Outset Notes

5.24 x 4.61 x .50 56,000 48,000 45,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. For detailed track versus allowable gross axle weight rating information when outset wheels are used, see 44,000 lb. Tandem Rating Chart, page 82. 

 6. The .50 in. wall thickness housings are not approved with suspension capacities rated above 50,000 lbs. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 53

46,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 46,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Standard Track SelecTTracTM Wide Track

D46-170 5.24 x 4.61 x .50 5.24 x 4.61 x .50 5.24 x 4.61 x .63

3.750/3.250 R

2

D463-P 5.24 x 4.61 x .56 Not Available 5.24 x 4.61 x .56 2

D46-170H, D46-590HP 5.24 x 4.61 x .63 Not Available 5.24 x 4.61 x .63 2

Gross Axle Ratings Based on the Use of SelecTTracTM or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track Width

SelecTTracTM

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .50 44,000 Not Available 2, 7

5.24 x 4.61 x .56 Not Available 44,000 2

5.24 x 4.61 x .63 Not Available 46,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

79 in. Maximum Track

(SelecTTracTM Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 44,000 40,000 Not Available 2, 4, 5, 7

5.24 x 4.61 x .56 46,000 Not Available 38,000 2, 4, 5

5.24 x 4.61 x .63 46,000 Not Available 42,000 2, 4, 5

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

76 in. Track

(SelecTTracTM Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 62,000 58,000 Not Available 2, 3, 7

5.24 x 4.61 x .56 64,000 Not Available 58,000 2 ,3

5.24 x 4.61 x .63 65,000 Not Available 62,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

79 in. Track 

(Select w/Outset)

82 in. Track 

(Wide w/Outset) Notes

5.24 x 4.61 x .50 58,000 52,000 Not Available 2, 3, 4, 7

5.24 x 4.61 x .56 60,000 Not Available 48,000 2, 3, 4

5.24 x 4.61 x .63 62,000 Not Available 52,000 2, 3, 4
Housing Structural Ratings

54 DAAG2014 March 2014

46,000 lb. Housing Structural Ratings (cont'd.)

Housing Wall Thickness Requirements for Various Non-Proprietary Suspensions (See Note 7)

Suspension Minimum Box Section 

Requirements (in.)

Manufacturer Model Type Application (H x W x T)

Chalmers 800-46 Rubber Spring walking beam Vocational 5.24 x 4.61 x .56

Hendrickson HAS 460 Trailing Arm Air Ride On-off highway 5.24 x 4.61 x .50

Hendrickson HMX 460 Rubber Spring walking beam On-off highway 5.24 x 4.61 x .50

Hendrickson HN 462 Rubber Spring walking beam Vocational 5.24 x 4.61 x .50

Hendrickson RT(E) 463 Steel Spring walking beam Vocational 5.24 x 4.61 x .50

Hendrickson RS 463 Rubber Spring walking beam Vocational 5.24 x 4.61 x .50

Hendrickson Primaax 460 Trailing Arm Air Ride On-off highway 5.24 x 4.61 x .50

Hendrickson R 463 Solid walking beam Vocational 5.24 x 4.61 x .50

Neway AD-246 Trailing Arm Air Ride Vocational 5.24 x 4.61 x .50

Neway ADZ-246 Trailing Arm Air Ride Vocational 5.24 x 4.61 x .50

Raydan Air Link Air Bag walking beam On-off highway 5.24 x 4.61 x .56

Reyco 102AR Trailing Arm Air Ride On-highway 5.24 x 4.61 x .50

Reyco 102W 4 spring On-highway 5.24 x 4.61 x .50

Ridewell RD202S Rubber Spring Torque Beam Vocational 5.24 x 4.61 x .56

Ridewell RAD-227C 8 Air Bag Beam Vocational 5.24 x 4.61 x .50

Ridewell RAD-241-OS Trailing Arm Air Ride Vocational 5.24 x 4.61 x .50

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 35.88 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. For detailed track versus allowable gross axle weight rating information when outset wheels are used, see 46,000 lb. Tandem Rating Chart, page 83. 

 6. The .50 in. wall thickness housings are not approved with suspension capacity ratings above 50,000 lbs. 

The .56 in. wall thickness housings are not approved with suspension capacities rated above 52,000 lbs. 

The .63 in. wall thickness housings are not approved with suspension capacities above 52,000 lbs. 

 7. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 40 in. for SelecTTracTM housings.
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 55

50,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 50,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Standard Track Wide Track

D50-170 5.24 x 4.61 x .63 5.24 x 4.61 x .63 3.750/3.250 R 2

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .63 47,500 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .63 50,000 42,000 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .63 65,000 62,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

82 in. Track 

(Wide w/Outset) Notes

5.24 x 4.61 x .63 62,000 52,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 35.88 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. The .63 in. wall thickness housings are not approved with suspension capacities above 52,000 lbs. 
Housing Structural Ratings

56 DAAG2014 March 2014

52,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 52,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type Notes

Standard Track Wide Track

D52-190P, D52-590P, DT521P 5.91 x 5.31 x .63 5.91 x 5.31 x .63 3.750/3.250 R 2

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

78.5 in. Maximum Track Width

Wide Track

81.0 in. Maximum Track Width

Wide-Wide Track Notes

5.24 x 4.61 x .63 52,000 48,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

82 in. Maximum Track

(Wide Track Housing)

85 in. Maximum Track

(Wide-Wide Track Housing) Notes

5.24 x 4.61 x .63 50,000 46,500 42,000 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

78.5 in. Track

(Wide Track Housing)

81.0 in. Track

(Wide-Wide Track Housing) Notes

5.24 x 4.61 x .63 66,000 63,000 56,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Standard w/Outset)

82 in. Track 

(Wide w/Outset)

85 in. Track 

(Wide-Wide w/Outset) Notes

5.24 x 4.61 x .63 63,000 53,000 46,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 35.88 in. and a maximum track width of 73 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. The .63 in. wall thickness housings are not approved with suspension capacities above 52,000 lbs. 
Housing Structural Ratings

Housing Structural Ratings

DAAG2014 March 2014 57

60,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 60,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Narrow/Stnd Track Wide Track

D60-190P, D60-590P 5.91 x 5.31 x .63 5.91 x 5.31 x .63 4.125/3.500 W 2

Gross Axle Ratings Based on the Use of Narrow or Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

72.5 in. Maximum Track Width

Narrow Track

76 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .63 60,000 58,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Narrow Track Housing)

78 in. Maximum Track

(Standard Track Housing)

80 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .63 57,500 53,000 49,500 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

72.5 in. Track 

(Narrow Track Housing)

74 in. Track

(Standard Track Housing)

76 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .63 70,000 68,000 66,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Track 

(Narrow w/Outset)

78 in. Track 

(Standard w/Outset)

80 in. Track 

(Wide w/Outset) Notes

5.24 x 4.61 x .63 66,000 64,000 62,000 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 35.88 in. and a maximum track width of 74 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. The .63 in. wall thickness housings are not approved with suspension capacities above 65,000 lbs. 
Housing Structural Ratings

58 DAAG2014 March 2014

70,000 lb. Housing Structural Ratings

Housing Dimensions

Drive Axle Model

(Nominal GAWR [See Note 1] - 70,000 lbs.)

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer) Spindle Type

Standard Track Wide Track

D70-590P 6.75 x 5.63 x .88 6.75 x 5.63 x .88 4.125/3.500 W

Gross Axle Ratings Based on the Use of Intermediate, Wide or Wide-Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

75 in. Maximum Track Width

Intermediate Track

80 in. Maximum Track Width

Wide Track

85 in. Maximum Track Width

Wide-Wide Track Notes

6.75 x 5.63 x .88 70,000 70,000 70,000 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Housing)

79 in. Maximum Track

(Intermediate Housing)

84 in. Maximum Track

(Wide Track Housing)

89 in. Maximum Track

(Wide-Wide Housing) Notes

6.75 x 5.63 x .88 Not Approved Not Approved Not Approved Not Approved 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

72 in. Track 

(Standard Track)

75 in. Track

(Intermediate Track)

80 in. Track

(Wide Track)

85 in. Track

(Wide-Wide Track) Notes

6.75 x 5.63 x .88 77,000 77,000 77,000 77,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard w/Outset)

79 in. Maximum Track 

(Inter w/Outset)

84 in. Maximum Track 

(Wide w/Outset)

89 in. Maximum Track 

(Wide-Wide w/Outset) Notes

6.75 x 5.63 x .88 Not Approved Not Approved Not Approved Not Approved 2, 3, 4

Notes: 1. Nominal gross axle weight rating (GAWR) is based on minimum axle mounting centers of 38 in. and a maximum track width of 72 in. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. The D70-590P is not approved with single outset wheels. 

 5. Dowel pins are not available on this housing. 
DAAG2014 March 2014 59

Tridem Load Ratings

Tridem Load Ratings

Tridem Load Ratings

Housing Dimensions

Drive Axle Model

[See Note 1]

Housing Box Section (in.)

(H x W x T) Spindle Diameters

(Inner/Outer)

Spindle 

Type Notes

Standard Track Wide Track

T60-174 5.24 x 4.61 x .50 5.24 x 4.61 x .50

3.750/3.250 R

1, 5

TD583-P 5.24 x 4.61 x .56 5.24 x 4.61 x .56 1

T69-170HP 5.24 x 4.61 x .63 5.24 x 4.61 x .63 1

T78-190P, T78-590P 5.91 x 5.31 x .63 5.91 x 5.31 x .63 1

Gross Axle Ratings Based on the Use of Wide Track Housings (lbs.)

Housing Box Section (in.)

(H x W x T)

78.5 in. Maximum Track Width

Wide Track Notes

5.24 x 4.61 x .50 Note 1 1, 2, 5

5.24 x 4.61 x .56 Note 1 1, 2

5.24 x 4.61 x .63 Note 1 1, 2

5.91 x 5.31 x .63 Note 1 1, 2

Gross Axle Ratings Based on the Use of Single Outset Wheels (lbs.)

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard Track Housing)

82 in. Maximum Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 Note 1 Note 1 1, 2, 4, 5

5.24 x 4.61 x .56 Note 1 Note 1 1, 2, 4

5.24 x 4.61 x .63 Note 1 Note 1 1, 2, 4

5.91 x 5.31 x .63 Note 1 Note 1 1, 2, 4

Gross Axle Ratings Based on Site Travel Conditions Only (lbs.) (See Note 3)

Housing Box Section (in.)

(H x W x T)

73 in. Track 

(Standard Housing)

78.5 in. Track

(Wide Track Housing) Notes

5.24 x 4.61 x .50 68,000 60,000 2, 3, 5

5.24 x 4.61 x .56 70,000 64,000 2, 3

5.24 x 4.61 x .63 72,000 69,000 2, 3

5.91 x 5.31 x .63 78,000 78,000 2, 3

Housing Box Section (in.)

(H x W x T)

76 in. Maximum Track 

(Standard w/Outset)

82 in. Maximum Track 

(Wide w/Outset) Notes

5.24 x 4.61 x .50 54,000 50,000 2, 3, 4, 5

5.24 x 4.61 x .56 59,000 57,000 2, 3, 4

5.24 x 4.61 x .63 69,000 63,000 2, 3, 4

5.91 x 5.31 x .63 75,000 69,000 2, 3, 4

Notes: 1. Maximum allowable gross axle weight ratings (GAWR) vary with ratio and track width. See charts on next page for values. 

 2. Track widths are nominal and may vary with wheel equipment. 

 3. Site travel: 5 miles per hour maximum speed with liftable axles raised. This condition shall not exceed 5% of the total operating miles of the vehicle. 

 4. Single tires with outset wheels beyond 2.0 in. are not approved. 

 5. The forward rear, wide track housing has a .63 in. wall thickness while the two rear most wide track housings are .50 in. thick. 

 6. The .50 in. wall thickness housings are not approved with suspension capacities above 63,000 lbs. 
60 DAAG2014 March 2014

Tridem Load Ratings

Tridem Load Ratings (cont’d.) Dana T60-174 Tire SLR ≤ 19.7 in.

Ratio

GAWR

Rating 

78.5 in. 

Wide Track

76 in.

Track

82 in.

Track

Standard 

Housing

Wide Track 

Housing

Single Tires 

Standard 

Housing

Single Tires 

Wide Track 

Housing

3.36 44,000 44,000 44,000 44,000

3.55 46,000 46,000 46,000 46,000

3.70 48,000 48,000 48,000 48,000

3.90 51,000 51,000 51,000 50,000

4.11 53,000 53,000 53,000 50,000

4.33 56,000 56,000 54,000 50,000

4.63 60,000 60,000 54,000 50,000

5.29 60,000 60,000 54,000 50,000

5.57 59,000 59,000 54,000 50,000

6.17 59,000 59,000 54,000 50,000

7.17 53,000 53,000 53,000 50,000

Dana T69-170HP 

Tire SLR ≤ 20.8 in.

Ratio

GAWR

Rating 

78.5 in.

Wide Track

76 in.

Track

82 in.

Track

Standard 

Housing

Wide Track 

Housing

Single Tires 

Standard 

Housing

Single Tires 

Wide Track 

Housing

3.42 51,000 51,000 51,000 51,000

3.58 53,000 53,000 53,000 53,000

3.73 55,000 55,000 55,000 55,000

3.91 58,000 58,000 58,000 58,000

4.10 61,000 61,000 61,000 61,000

4.30 64,000 64,000 64,000 63,000

4.56 68,000 68,000 68,000 63,000

4.78 69,000 69,000 69,000 63,000

5.25 69,000 69,000 69,000 63,000

5.38 69,000 69,000 69,000 63,000

5.57 69,000 69,000 69,000 63,000

6.14 69,000 69,000 69,000 63,000

6.83 66,000 66,000 66,000 63,000

7.17 69,000 69,000 69,000 63,000

Dana T78-190P, T78-590P

Tire SLR ≤ 20.8 in.

Ratio GAWR

Rating 

78.5 in.

Wide Track

76 in.

Track

82 in.

Track

190P 590P Standard 

Housing

Wide Track 

Housing

Single Tires 

Standard 

Housing

Single Tires 

Wide Track 

Housing

3.42 4.75 60,000 60,000 60,000 60,000

3.58 4.99 60,000 60,000 60,000 60,000

3.73 5.19 60,000 60,000 60,000 60,000

3.91 5.44 60,000 60,000 60,000 60,000

4.10 5.70 61,000 61,000 61,000 61,000

4.30 5.98 64,000 64,000 64,000 64,000

4.56 6.34 68,000 68,000 68,000 68,000

4.78 6.65 71,000 71,000 71,000 69,000

5.25 7.30 78,000 78,000 75,000 69,000

5.38 7.48 78,000 78,000 75,000 69,000

5.57 7.75 78,000 78,000 75,000 69,000

6.14 8.55 78,000 78,000 75,000 69,000

6.83 9.51 77,000 77,000 75,000 69,000

7.17 9.97 71,000 71,000 71,000 69,000

Dana TDT583-P

Tire SLR ≤ 20.1 in.

Ratio GAWR

Rating 

78.5 in.

Wide Track

76 in.

Track

82 in.

Track

Hi Low Standard 

Housing

Wide Track 

Housing

Single Tires 

Standard 

Housing

Single Tires 

Wide Track 

Housing

3.70 5.04 54,000 54,000 54,000 54,000

3.90 5.32 58,000 58,000 58,000 57,000

4.11 5.60 59,000 59,000 59,000 57,000

4.33 5.90 55,000 55,000 55,000 55,000

4.56 6.21 52,000 52,000 52,000 52,000

4.88 6.64 52,000 52,000 52,000 52,000

5.43 7.39 49,000 49,000 49,000 49,000

6.17 8.40 44,000 44,000 44,000 44,000
DAAG2014 March 2014 61

Drive Axle Model Identification

Drive Axle Model Identification

Spicer® Drive Axle Model Identification

Note: All options are not available for each model.

D - Dual Drive Forward Axle 

with Interaxle Differential

G - Single Rear Axle (Global)

R - Dual Drive Rear Axle

S - Single Rear Axle (N.A.)

T - Tridem Configuration

GAW Rating x 1000 lbs.

Options

C - Controlled Traction 

D - Differential Lock 

E - High Entry Single 

F - Flipped/Rolled Over 

H - Heavy Wall 

I - Integral Brake 

L - Limited Slip 

N - No Spin® Differential 

O - Offset Change 

P - Lube Pump 

R - Retarder Ready 

U - Unitized Spindle 

W - Wide Track Housing 

Gearing

S - Single Reduction

D - Differential Lock

Design Level

Design Level

Series

Head Assembly Series

GAW Rating

x 1000 lbs. (N.A.) “-”

x 1 Tn (Global) “.”

Gear Type

1 - Standard Single Reduction

2 - Dual Range

5 - Helical Reduction

6 - Helical Overdrive

S 26 – 1 7 0 D

23 09 0 S
62 DAAG2014 March 2014

Drive Axle Model Identification

T D S 58 3 – P

D S 40 4 – (P)

Spicer® Drive Axle Model Identification (cont’d.)

Gearing

S - Single Reduction

D - Differential Lock

D - Forward Tandem Axle

R - Rear Tandem Axle

D - Tridem Forward Axle with 

Interaxle Differential

R - Tridem Rear Axle

(P) - Optional Lube Pump

Tridem Axle P - Lube Pump

Design Level

Design Level

GAW Rating

x 1000 lbs. (N.A.) “-”

Gear Type x 1 Tn (Global) “.”

S - Single Reduction

D - Single Reduction with 

Drive-Controlled Wheel 

Differential Lock

T - Dual Range*

P - Planetary Double Reduction

* Requires protective shift system

GAW Rating x 1000 lbs.

Note: All options are not available for each model.
DAAG2014 March 2014 63

Drive Axle Identification

Drive Axle Identification

Spicer® Drive Axle Identification

Drive Axle Head Assembly

Parts

1 - Country of origin

2 - Axle model identification

3 - Specification number assigned to the axle 

built by Dana. Identifies all component parts 

of the axle including special OEM requirements 

such as yokes or flanges.

1 - ID tag

1

2

4 - OEM part number assigned to the axle build

5 - Carrier assembly serial number assigned 

by the manufacturing plant

6 - Axle gear ratio

7 - Carrier assembly production or service 

part number

2 - Axle shaft part number

Forward Axle

Axle Housing Axle Shaft

Rear Axle (Top View)

PT. NO.

HSG. CAP. LBS.

HSG . I.D. NO.

HOUSING M ADE IN

Spicer ®

1

2

3

4

5

6

7
64 DAAG2014 March 2014

Drive Axle Identification

Spicer® Drive Axle Identification

Parts Identification

Ring Gear and Pinion

Note: Ring gear and drive pinion are matched parts and must be replaced in sets.

1 - Part number

2 - Number of ring gear teeth

3 - Manufacturing numbers

4 - Matching gear set numbers

5 - Number of pinion teeth

6 - Date code

7 - Indicates genuine Spicer®

 parts

8 - Heat code

1

7

5 2

7

1

4

3

6

8

6

4

8 3
DAAG2014 March 2014 65

Nomenclature

Nomenclature

Nomenclature – General

Tandem Axle Assembly

4 Z

Z

1

2

3

1

2

1 - Carrier fasteners

2 - Carrier assembly

3 - Forward axle assembly

4 - Rear axle assembly

Section Z - Z

Width (W)

Wall Thickness (T)

Axle Housing Box

Height (H)
66 DAAG2014 March 2014

Nomenclature

Nomenclature – General

Housing and Output Shaft Assembly

1 - Output shaft nut

2 - Output yoke

3 - Output seal

4 - Output shaft bearing snap ring

5 - Outer bearing cup

6 - Outer bearing cone

7 - Inner bearing cone

8 - Inner bearing cup

9 - Output shaft

10 - Rear cover

11 - Rear cover capscrew

12 - Fill plug

13 - Rear cover nut

14 - Washer

15 - Stud

16 - Spindle nut - outer

17 - Locking ring

18 - Spindle nut - inner

19 - Axle housing

20 - Breather

21 - Breather hose

22 - Carrier capscrew

23 - Nut

24 - Washer

25 - Stud

26 - Drain plug

27 - Axle shaft

* Varies - see page 70.

1

2

3 4

5

6

7

8

9

19

11

10

12

13

14

16 17 18

27

15

26

2524 23

22

21

20
DAAG2014 March 2014 67

Nomenclature

Nomenclature

Nomenclature – General

Forward Axle Pinion Assembly (Tandem Axle)

Rear Axle Pinion Assembly (Single Axle)

1 - Pinion

2 - Pinion bearing cone - inner

3 - Pinion bearing cup - inner

1 - Pinion

2 - Pinion bearing cone - inner

3 - Pinion bearing cup - inner

4 - Pinion helical gear

5 - Pinion bearing spacer

6 - Pinion bearing cup - outer

4 - Pinion bearing spacer

5 - Pinion bearing cup - outer

6 - Pinion bearing cone - outer

7 - Pinion bearing cone - outer

8 - Pinion nut

7 - Oil seal

8 - Yoke

9 - Pinion nut

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

9
68 DAAG2014 March 2014

Nomenclature

Nomenclature – General

Wheel Differential

1

2

3

4

5

7

6 8

6

9

11

12

10

1 - Threaded bearing adjuster 

(flange half)

2 - Bearing cone (flange half)

3 - Differential case (flange half)

4 - Ring gear

5 - Ring gear bolt 

6 - Side gear

7 - Side pinion

8 - Differential spider

9 - Differential case (plain half)

10 - Differential case (plain half) 

wheel differential lock

11 - Bearing cone (plain half)

12 - Threaded bearing adjuster 

(plain half)
DAAG2014 March 2014 69

Nomenclature

Nomenclature

Nomenclature – General

Power Divider 1

19

20

21

22

23

24

42 41

40

39

25

26

27 28 11

12

11

13

30 31

32

33

34

35

38 37

36

29

2

3

4

5

6

7

8

9

10

14

15 16

17

18

1 - Output shaft nut

2 - Output yoke

3 - Output seal

4 - Output shaft bearing snap ring

5 - Outer bearing cup

6 - Outer bearing cone

7 - Inner bearing cone

8 - Inner bearing cup

9 - Output shaft

10 - Seal manifold

11 - Clamp

12 - Seal manifold feed tube

13 - Sump screen

14 - Output side gear bearing cup

15 - Output side gear bearing cone

16 - Pin

17 - Output side gear

18 - Pump

19 - Interaxle differential

20 - Helical side gear

21 - Thrust washer

22 - Lockout sliding clutch

23 - Shift fork spring

24 - Shift fork assembly

25 - V-ring

26 - Input shaft

27 - Input shaft bearing cone

28 - Carrier housing

29 - Locking capscrew

30 - Input cover

31 - Input cover capscrew

32 - Bearing cup and cage

33 - Input seal

34 - Input yoke

35 - Input nut

36 - Piston

37 - O-ring

38 - Piston cover

39 - Pinion cover

40 - Input cover capscrew

41 - Input cover

42 - Carrier housing
70 DAAG2014 March 2014

Spindle Nut Systems

Three-piece Dowel-type Lock Washer System

1 - Inner nut

2 - Dowel pin

3 - Dowel-type lock washer

4 - Outer nut

Spindle Nut Systems

Three-piece Tang-type Lock Washer System

1 - Inner nut

2 - Tang-type lock washer

3 - Outer nut

Four-piece Tang/Dowel-type Lock Washer System

1 - Inner nut

2 - Dowel pin

3 - Dowel-type lock washer

4 - Tang-type lock washer 

5 - Outer nut

Note: Dana does not specify spindle retention systems. This is the responsibility of the OEM.

4

4

5

3

3

3

2

2

2

1

1

1
DAAG2014 March 2014 71

Axle Shaft Flange to Hub

Axle Shaft Flange to Hub

Axle Shaft Flange to Hub

Gasket

Gasket

Hub

Hub

Axle shaft

Axle shaft

Stud nut

Stud nut

Taper dowel

Lock

washer

Lock

washer

With tapered holes in axle shaft flange

With straight holes in axle shaft flange
72 DAAG2014 March 2014

Power Divider Operation

Power Divider Operation 

Power Flow and Torque Distribution

In operation, the power divider accepts torque from the vehicle 

driveline and distributes it equally to the two axles.

This assembly is of the two-gear design consisting of an input 

shaft, interaxle differential, output shaft, and two constant-mesh 

helical gears.

The interaxle differential compensates for minor variations 

in speed between the two axles, the same way the wheel 

differential works between the two wheels of a single drive axle. 

This unit also acts as a central point in distribution of torque to 

the two axles.

The power divider also includes a driver-controlled, air-operated 

lockout. When lockout is engaged, it mechanically prevents 

interaxle differentiation for better performance under poor 

traction conditions.

With Lockout Disengaged

(Interaxle Differential Is Operating)

1 - Input torque

2 - Lockout disengaged

3 - Forward axle torque is transmitted from the helical 

side gear through the pinion helical gear, drive 

pinion, ring gear, wheel differential, and axle shafts.

4 - Rear axle torque is transmitted from the output 

shaft side gear through the output shaft, interaxle 

driveline, drive pinion, ring gear, wheel differential, 

and axle shafts.

5 - Input torque (power flow) from the vehicle driveline 

is transmitted to the input shaft and the interaxle 

differential spider. The differential distributes torque 

equally to both axles.

5

1

2

3

4
DAAG2014 March 2014 73

Power Divider Operation

Power Divider Operation

Power Divider Operation 

Power Flow and Torque Distribution (cont’d.)

With Lockout Engaged

(Interaxle Differential Is Not Operating)

Lockout should only be engaged when both axles are rotating 

at the same speed. Operation should be limited to low-traction 

situations and should be disengaged when normal traction 

returns. Failure to do so will result in poor handling and damage 

to the axle components.

Note: Varied road surface conditions can result in unequal 

torque distribution between the two axle assemblies.

 Prolonged operation with the lockout engaged 

can damage axle and driveline components.

1 - Input torque

2 - Lockout engaged

3 - Forward axle torque is transmitted from the helical 

side gear through the pinion helical gear, drive 

pinion, ring gear, wheel differential, and axle shafts.

4 - Rear axle torque is transmitted from the output shaft 

side gear through the output shaft, interaxle driveline, 

drive pinion, ring gear, wheel differential, and axle 

shafts.

5 - Input torque (power flow) from the vehicle driveline 

is transmitted directly to the helical side gear and the 

output shaft. A positive drive is provided to both axles 

for maximum traction under adverse road conditions.

1

2

3

5

4
74 DAAG2014 March 2014

Wheel Differential Lock

Wheel Differential Lock

The Spicer® wheel differential lock is an optional feature for 

Spicer axles. In operation, it positively locks the wheel 

differential to provide improved traction under adverse 

road conditions.

The differential lock is driver-controlled through an electric 

switch or air valve mounted in the cab. The locking mechanism 

is air-operated to engage a mechanical clutch and lock the wheel 

differential. It is spring-operated to disengage the lock and 

permit the wheel differential to function normally.

The wheel differential lock consists of three major assemblies.

 • Shift Cylinder Assembly: Operates a shift fork and push 

rod assembly.

 • Shift Fork and Push Rod Assembly: Engages and 

disengages the differential lock curvic clutch assembly.

 • Curvic Clutch Assembly: Consists of a sliding clutch 

splined to an axle shaft and a fixed clutch which is splined 

to the differential case hub.

The differential lock also includes a selector switch (electric) 

which senses clutch engagement and sends an electrical signal 

to a cab-mounted indicator light (or an audible signal device).

1 - Sliding clutch

2 - Spring

3 - Clutch fork

4 - Piston and rod

5 - O-ring

6 - Piston cover

7 - Washer

8 - Switch

9 - Pin

10 - Carrier

1 9

3

6

5

4

7

2

8 10
DAAG2014 March 2014 75

Wheel Differential Lock

Wheel Differential Lock

Wheel Differential Lock (cont’d.)

Differential Lock Engaged

Air pressure applied to the shift cylinder moves the piston, 

push rod, and shift fork, and the sliding curvic clutch engages 

the fixed curvic clutch.

The sliding clutch is splined to the axle shaft. The fixed 

clutch is splined to the differential case hub. Engaging the 

two clutches locks the wheel differential, preventing wheel 

differential action.

Differential Lock Disengaged

When air pressure at the shift cylinder is released, a compression 

spring (mounted on the push rod) moves the push rod, shift fork, 

and sliding clutch as an assembly. The sliding clutch moves out 

of engagement with the fixed clutch. The wheel differential is 

unlocked and operates normally.

Differential Lock Engagement Indicator

Differential lock engagement is detected by a switch (electric) 

mounted on the differential carrier. An actuator, mounted in the 

piston cover, operates the switch.

When the shift fork moves to engage the differential lock, the 

push rod actuator moves away from the switch, allows the switch 

to close, and sends an electrical signal to turn on a cab-mounted 

indicator light (or an audible signal).

When the shift fork moves to disengage the differential lock, the 

compression spring also moves the push rod actuator to contact 

the switch. The switch is opened and turns off the cab-mounted 

indicator light (or the audible signal).

5

3

4

2 1

6 7

5

3

4

2 1

6 7

Differential Lock Engaged

1 - Spring is compressed

2 - Shift fork

3 - Piston and rod

4 - Selector switch

5 - Air pressure applied engages clutches

6 - Fixed clutch splined to differential case

7 - Sliding clutch splined to axle shaft and 

 engaged with fixed clutch

Differential Lock Disengaged

1 - Spring is decompressed

2 - Shift fork

3 - Piston and rod

4 - Selector switch

5 - Air pressure released disengages clutches

6 - Fixed clutch splined to differential case

7 - Sliding clutch splined to axle shaft
76 DAAG2014 March 2014

Dual Range Tandem Axle Drives

Dual Range Tandem Drive Axles

Description and Operation

Gearing and Torque Distribution - Dual Range Gearing

Two-speed, single or tandem, are dual range shiftable axles. 

They provide low and high range gearing and are designed for 

heavy-duty service in on-off highway operations. Low range for 

deep gear reduction and slow speed hauling off-highway. High 

range for cruising speeds on-highway. 

The complete tandem axle assembly includes two axle units, 

each with double gear reduction capability coupled by a 

two-gear power divider.

The gearing for each axle is a 

combination of a spiral bevel ring gear 

and pinion and a planetary unit. 

First reduction (High Range) is provided 

by the spiral bevel gearing.

Second reduction (Low Range) is through 

the planetary gearing. Four planetary idler 

pinions are confined within the ring gear 

internal teeth. The planetary gears rotate 

around a sliding clutch gear.

Each axle is equipped with a shift unit, 

which operates the sliding clutch gear to 

provide a means for selecting the axle 

range. Range selection is accomplished 

through the movement of the sliding 

clutch gear in and out of engagement 

with low- and high-speed clutch plates.

The sliding clutch gear is locked into the 

high-speed clutch plate and rotates as 

part of the differential assembly. The 

planetary pinions are stationary and 

the axle uses only the single reduction 

of the ring gear and pinion. Power flow 

is through the drive pinion, ring gear, 

differential unit, and axle shafts.

The sliding clutch gear is shifted into 

engagement with the low-speed clutch 

plate (an integral part of the bearing 

adjuster). The sliding clutch is held 

stationary and the planetary pinions are 

forced to rotate around it. Power flow 

is now through drive pinion, ring gear, 

planetary gearing, differential unit, and 

axle shafts. The axle uses two reductions 

to multiply torque. The planetary unit 

adds approximately 36% more reduction 

to the primary gear set. Torque is 

multiplied on an equivalent basis.

High-speed

Clutch Plate High-speed

Low-speed Clutch Plate

Clutch Plate 

(Bearing Adjuster)

Low-speed

Clutch Plate 

(Bearing Adjuster)

Sliding

Clutch Gear

Sliding

Clutch Gear

Ring

Gear Ring

Gear

Idler

Pinion 

Rings

Idler

Pinion 

Rings Planetary

Pinions

Planetary

Pinions
DAAG2014 March 2014 77

Reduction Axles

Planetary Double 

Planetary Double 

Reduction Axles

Planetary Double Reduction Axles

Description and Operation

The planetary double reduction axles share their basic design 

concepts and many components with the dual range tandem. 

The principle variation is the permanent engagement of the 

double reduction feature. A stationary sun gear, fixed in 

engagement with the low-speed clutch plate, replaces the sliding 

clutch gear and provides continuous double reduction operation 

in the same manner as the dual range axle when in Low Range.

First Reduction:

Pinion and

Ring Gear

Planetary Double Reduction Gearing

Secondary

Reduction:

Planetary

Gearing
78 DAAG2014 March 2014

Track, SLR, SMC

Track, SLR, SMC

TRACK – The distance between the dual tire centerlines or the distance 

between the tire centerlines on a single tire.

SLR (Static Loaded Radius) – The distance from the centerline of the 

axle to the ground, underrated tire capacity, with the tire at rest.

SMC (Suspension Mounting Centers) – The distance between suspension 

mounting points on an axle.
DAAG2014 March 2014 79

Super Single Tires /

Offset Wheels

Super Single Tires /

Offset Wheels

Super Single Tires / Offset Wheels

• Outset (positive) – The tire centerline is positioned outboard of the wheel 

mounting face.

• Inset (negative) – The tire centerline is positioned inboard of the wheel 

mounting face.

Super Singles or Wide-Based Tires – Term associated with single tire drive 

axle arrangements typically used with outset or zero offset wheels (in place 

of dual tire arrangements).
80 DAAG2014 March 2014

Ratings Charts

40,000 lb. Ratings

33000 

34000 

35000 

36000 

37000 

38000 

39000 

40000 

41000 

70 71 72 73 74 75 76 77 

GAWR (lb) 

Track (in) 

D404, DSP40, DST40, D40-145, D40-155, D40-156 

21.1 in. Max. Tire SLR; 35.9 in. Min. Spring Mounting Centers 

Standard Track (64.88 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

33000 

34000 

35000 

36000 

37000 

38000 

39000 

40000 

41000 

70 71 72 73 74 75 76 77 

GAWR (lb) 

Track (in.) 

D405, DSP41, DST41, DSH40, D40-145H, D40-155/6H, D40-170 

21.1 in. Max. Tire SLR: 35.9 in. Min. Suspension Mounting Centers 

Standard Track (64.88 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

D404, DSP40, DST40, D40-145, D40-155, D40-156

21.1 in. Max. Tire SLR; 35.9 in. Min. Spring Mounting Centers

Standard Track (64.88 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

D405, DSP41, DST41, DSH40, D40-145H, D40-155/6H, D40-170

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Mounting Centers

Standard Track (64.88 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

Track (in.)

Track (in.)

GAWR (lbs.) GAWR (lbs.)
DAAG2014 March 2014 81

Ratings Charts

Ratings Charts

40,000 lb. Ratings (cont’d)

33000 

34000 

35000 

36000 

37000 

38000 

39000 

40000 

41000 

73 74 75 76 77 78 79 80 

GAWR (lb) 

Track (in) 

D404/5, DSP40/1, D40-145S/H. D40-155S/H, D40-156S/H, DSH40, D40-170S 21.1 in. Max. Tires SLR: 40.0 in. Min Spring Mounting Centers 

SelecTTracTM (67.87 in. Inner Bearing Shoulder to Inner Bearing Shoulder) 

9.5 mm wall 11 mm wall 12.5 mm wall 

33000 

34000 

35000 

36000 

37000 

38000 

39000 

40000 

41000 

76.0 77.0 78.0 79.0 80.0 81.0 82.0 83.0 

GAWR (lb) 

Track (in.) 

D404, DSP40, DST40, DSH40, D40-155/6W, D40-170 21.1 Max. 

Tire SLR; 35.9 In. Min. Suspension Mounting Center Wide Track (70.55 in. 

Inner Bearing Shoulder to Inner Bearing Shoulder) 

12.5 mm wall 16 mm wall 

D404/5, DSP40/1, D40-145S/H, D40-155S/H, D40-156S/H, DSH40, D40-170S

21.1 in. Max. Tire SLR; 40.0 in. Min. Spring Mounting Centers

SelecTTracTM (67.87 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

 9.5 mm wall 11 mm wall 12.5 mm wall

 12.5 mm wall 16 mm wall

D404, DSP40, DST40, DSH40, D40-155/6W, D40-170W

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Mounting Centers

Wide Track (70.55 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

76 77 78 79 80 81 82 83

Track (in.)

Track (in.)

GAWR (lbs.) GAWR (lbs.)
82 DAAG2014 March 2014

Ratings Charts

44,000 lb. Ratings

42000 

42500 

43000 

43500 

44000 

44500 

45000 

70 71 72 73 74 75 76 77 

GAWR (lb) 

Track (in) 

DSH44

21.1 In. Max Tire SLR; 35.9 In. Min. Suspension Centers 

Standard Track (64.88 In. Inner Bearing Shoulder to Inner Bearing Shoulder) 

DSH44

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Centers

Standard Track (64.88 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

Track (in.)

GAWR (lbs.)

38000 

39000 

40000 

41000 

42000 

43000 

44000 

45000 

73 74 75 76 77 78 79 80 

GAWR (lb) 

Track (in) 

DSH44

21.1 In. Max. Tire SLR; 35.9 in Min. Suspension Mounting Centers 

SelecTTracTM (67.87 in. Inner Bearing Shoulder to Inner Bearing Shoulder) 

DSH44

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Mounting Centers

SelecTTracTM (67.87 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

Track (in.)

GAWR (lbs.)

33000 

35000 

37000 

39000 

41000 

43000 

45000 

76 77 78 79 80 81 82 83 

GAWR (lb) 

Track (in) 

DSH44 21.1 in. Max. Tire SLR; 35.9 in. Min Suspension Mounting Centers 

Wide Track (70.55 in. Inner Bearing Shoulder to Ineer Bearing Shoulder) 

DSH44

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Mounting Centers

Wide Track (70.55 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

Track (in.)

GAWR (lbs.)
DAAG2014 March 2014 83

Ratings Charts

Ratings Charts

46,000 lb. Ratings

34000 

36000 

38000 

40000 

42000 

44000 

46000 

48000 

76 77 78 79 80 81 82 83 

GAWR (lb) 

Track (in) 

D46-170W, D463-P, D46-590W 21.1 in. Max. Tire SLR; 35.9 in Min. Suspension Mounting Centers 

Wide Track (70.55 in. Inner Bearing Shoulder to Inner Bearing Shoulder) 

14 mm wall 16 mm wall 

 12 mm wall 14 mm wall 16 mm wall

Track (in.)

GAWR (lbs.) GAWR (lbs.)

44000 

44500 

45000 

45500 

46000 

46500 

47000 

70.0 71.0 72.0 73.0 74.0 75.0 76.0 77.0 

D46-170, D463-P, D46-170H, D46-590H

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Mounting Centers

Standard Track (64.88 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

34000 

36000 

38000 

40000 

42000 

44000 

46000 

48000 

0.0 2.0 4.0 6.0 8.0 10.0 12.0 

D406-170W, D463-P, D46-590W

21.1 in. Max. Tire SLR; 35.9 in. Min. Suspension Mounting Centers

Wide Track (70.55 in. Inner Bearing Shoulder to Inner Bearing Shoulder)

 14 mm wall 16 mm wall

Track (in.)

70 71 72 73 74 75 76 77

76 77 78 79 80 81 82
84 DAAG2014 March 2014

Glossary

ABA (Automatic Brake Adjuster) - Also called an Automatic 

Slack Adjuster (ASA), this is a lever connecting the brake 

chamber push rod with the foundation brake camshaft. It 

provides torque to rotate the brake camshaft when the brake 

treadle is depressed. It also provides a means of automatically 

adjusting clearance between brake shoes and the drum to 

compensate for lining wear. Some brake adjusters require 

manual adjustment. 

ABS (Anti-lock Brake System) - Electronically monitors wheel 

speed and prevents wheel lockup by rapidly cycling the brakes 

during panic stops and when stopping on low-friction surfaces. 

ABS Control Valves - Control valves that are actuated by the 

ABS Electronic Control Unit (ECU) to ensure wheels are optimally 

braked. On a tractor, they are called ABS modulator valves. On a 

trailer, they’re called ABS relay valves. 

A/C Centers - The distance from the centerline of one brake 

chamber to the other. 

Ackermann Geometry - The relative angular movements of 

the front wheels while traveling along a curved path. (A double 

pivoting steering system, where the outer tie rod arms are 

bent slightly inward so that when a vehicle is making a turn 

the wheels toe out and the inside wheel will turn more sharply 

than the outer wheel.) This is done to compensate for the 

greater distance the outside wheel must travel. These angular 

movements relate to the length of wheelbase and the width 

of track. True Ackermann geometry includes the Jeantaud 

modification to Rudolph Ackermann’s original principle. 

Active Suspension - While conventional suspension uses 

springs and shock absorbers to isolate the vehicle from the 

bouncing movement of the wheels when it contacts rough roads, 

active suspension uses power actuators that are controlled by 

a computer. These actuators place the wheels of the vehicle 

in the best position to accommodate rough roads as well as 

compensate for different load levels. 

Actuate - To initiate mechanical motion of a brake system 

component. 

Actuator - A device that physically initiates mechanical motion 

of a brake system component. 

ADB - See “Air Disc Brakes.” 

ADR 35 (Australian Design Rule 35) - Specifies braking 

requirements under normal and emergency conditions. 

Aftercooler - Optional device that condenses and eliminates 

water from air pressurized by the compressor. 

Air Build-Up - Process of compressor building pressure to a 

predetermined maximum level, usually 100-120 psi, within the 

brake system air tanks. 

Air Compressor - Engine-driven via a belt or direct gear, the 

compressor pressurizes the air tank. 

Air Compressor Cut-Out - Predetermined point at which the air 

governor halts compression of air by the compressor. 

Air Disc Brakes - Air-actuated brakes, which upon application, 

employ a caliper to clamp two brake pads against a rotor. Air 

discs, compared with drum-type brakes, have superior ability 

to resist fade. 

Air Dryer - A filter, typically containing a desiccant, which 

is installed between the compressor and service reservoir to 

remove water and vapor plus oil blow-by from the compressor. 

Air Gauge - Dash-mounted gauge indicating air pressure in 

terms of pounds per square inch (psi). 

Air Governor - Controls the compressor unloader mechanism 

and also maintains system air pressure between predetermined 

minimum and maximum levels, usually between 90-120 psi. 

Air Over/Under - In relation to suspensions. 

 Overslung - Suspension arm goes above or over the 

axle air bag. 

 Underslung - Suspension arm goes below or under 

the axle air bag. 

Air System Balance - Can be separated into two different 

aspects: pressure level balance and timing balance. Air system 

balance deals primarily with the vehicle air system components 

that directly control the actuation of the service brakes during 

normal stops, foot control valve, check valves, relay valves and 

their arrangement or system design. Their purpose is to balance 

the time it takes air pressure to build uniformly at all wheel ends. 

Air Tank - A reservoir for compressed air. Typically, a 

combination vehicle has several tanks: three in the tractor and 

one per trailer. The tractor’s supply air tank (formerly “wet tank”) 

receives air from the compressor and delivers it to the primary 

and secondary air tanks in the tractor. A check valve on each 

tank prevents total air loss in the event of a leak. 

Alcohol Evaporator - Optional device, installed in compressor 

discharge line between the compressor and supply air tank, 

which injects alcohol mist into the air flow to reduce the risk of 

freeze up. It’s not normally used in a vehicle with an air dryer.

AL Factor - A mathematical expression of the brake adjuster and 

brake chamber combination. “A” equals the effective area, in 

square inches, of the brake chamber (e.g., Type 30 chamber has 

effective area of 30 sq. in.). “L” equals the effective length, in 

inches, of the slack adjuster. For example, 30 x 6 in. = 180. 

Alignment - Method of maintaining proper relationship between 

all components of the steering system. 
DAAG2014 March 2014 85

Glossary

Glossary

Amboid Gear - Modified Spiral Bevel Gear that allows the pinion 

to be positioned above the ring centerline. 

Analog Processing - A method of processing information used 

in older ABS control units. Today’s Electronic Control Units 

(ECUs) use digital processing, which is many times faster and 

more reliable. 

Anchor Pin - A pin or pins used to retain brake shoes within the 

brake assembly. 

Anti-Compounding - A system that prevents application of 

service brakes from compounding the force exerted by parking 

brakes. This guards against damage to brake components due to 

excessive loads. 

Anti-lock Brake System - See “ABS.” 

Application Time - Time elapsed between depression of the 

brake treadle and engagement of the linings with the drums 

(or, per FMVSS 121, the point at which all service chambers 

reach 60 psi). 

Application Valve - Air valve, such as foot valve or trailer 

control valve, which controls the pressure delivered to the 

brake chambers. 

ASR (Anti-Spin Regulation) - See “ATC.”

ATC (Automatic Traction Control) - Also called ASR, it’s an 

optional system that is available on 4- and 6-channel ABS 

systems. Automatic traction control minimizes wheel slipping 

during acceleration by controlling both the engine throttle and 

brake pressures. 

Automatic Brake Adjuster - See “ABA.” 

Automatic Traction Control - See “ATC.” 

Auxiliary Lift Axle - An extra axle often kept in a lifted position 

and only dropped to the pavement when its extra load-carrying 

capacity is needed. 

Auxiliary Retarder - See “Retarder.” 

Auxiliary Transmission - Additional gear box increasing the 

gear ratio combinations when used with main transmission or 

multi-speed axles. 

Axle Carrier Assembly - Portion of the axle assembly that 

contains the drive gears and differential. To complete the axle 

assembly, the carrier assembly is combined with the housing. 

Axle, Live - Driven Axle. 

Axle Mounting Centers - Also referred to as the “Suspension 

Mounting Centers.” This is the distance between centerlines of 

where the suspension clamps to the axle. 

Axle Shaft - Transmits torque from the wheel differential to the 

wheel equipment. 

Axle Shaft Floating - Shaft carries no vehicle loads, but 

transmits torque. 

Axle Shaft Semi-Floating - Shaft carries vehicle loads as well 

as torque. 

Axle Shift System - The actual control mechanism that is 

employed to control movement of a shift fork or sliding clutch 

to vary the axle ratio. Three general types are employed for 

this purpose: 

 1. Air shift system 

 2. Electric over air shift system 

 3. Electric shift system

Axle Spindle - Used on a full floating housing design, supports 

the wheel end system. 

BCCC Dimension - Distance from the Brake Shoe centerline to 

the Brake Chamber centerline. 

Beam Drop - Distance from the kingpin to spindle intersection to 

the spring-mounting pad surface. 

Bearing Shoulder to Bearing Shoulder Dimension - Distance 

from the machined inner bearing contact point on one side of 

the axle to the machined inner bearing contact point on the 

other side. 

Belleville Washer - Also known as coned-disc springs or 

Belleville disc springs. They provide very high loads at small 

deflection and also maintain a constant force regardless of 

dimensional variations due to wear, temperature changes or 

tolerances. 

Bell-Mouthed Drum - Drum with variation of inner diameter 

(i.e., greater at open end), preventing full contact with brake 

lining. 

Blue Drum - Brake drum with friction surface turned blue from 

high temperature. High temperature may result from dragging of 

brakes caused by weak return springs. Blue drum also may result 

from lack of brake balance (i.e., excessive brake torque at wheel 

with blue drum and lack of brake torque and other wheel ends). 

Bogie - Combination of two axles usually pivoting about a 

common trunnion. 

Brake Adjuster - See “Slack Adjuster.” 

Brake Balance - Balance is achieved when all brakes on all 

axles do their fair share of the work. The four types of brake 

balance are: pneumatic, thermal, timing, and torque. 

Brake Block - Friction material, also known as brake lining, 

attached to a brake shoe. Disc brakes use pads with friction 

material. 
86 DAAG2014 March 2014

Glossary

Brake Chamber - Device inside which a diaphragm converts air 

pressure to mechanical force, via a push rod, for brake actuation. 

Consists of service chamber or service chamber/spring chamber. 

For example: A 30/36 chamber consists of a Type 30 service 

chamber and a Type 36 spring chamber. See “Service Brake” 

and “Spring Brake.” 

Brake Chamber Diaphragm - Compression molded device 

within a brake chamber that converts air pressure to mechanical 

force via a push rod. The size of the brake chamber correlates 

with the effective area of the diaphragm. A Type 30 chamber 

diaphragm has an effective area of 30 sq. in. 

Brake Drag - Failure of one or more brakes to release 

immediately and/or completely after a driver removes his foot 

from the brake treadle. Constant drag, unrelated to a brake 

application, also can exist. See “Quick-Release Valve.” 

Brake Drum - Attached to the hub. Converts kinetic energy from 

the shoe and lining assembly to heat and transfers that heat 

away from the brake surface to dissipate into the atmosphere 

over time. The majority of drums are entirely of cast iron. 

Generally these are divided into three service-rating codes based 

on application. There is standard duty, heavy duty, and extra 

heavy duty. In addition, there are inboard mounted drums (with 

spoke wheels) and outboard mounted drums (with hubs). The 

other brake drum is the steel jacketed type. This consists of a 

steel mounting face with a cast iron braking surface insert. 

Brake, Engine - See “Engine Brake.” 

Brake, Exhaust - See “Exhaust Brake.” 

Brake Fade - There are many types and causes of braking 

fade. Fade may result, for example, from a reduction in friction 

between linings and drums caused by exposure to water. Most 

typically, however, fade involves a reduction in braking force 

experienced when dragging brakes on a long grade. If brakes 

are maladjusted, an overheated drum may expand to the degree 

that push rod travel is insufficient to fully actuate the brakes. 

This is one example of mechanical fade, which also may result 

from various mechanical defects (e.g., scored drums) within 

the foundation brake system. In contrast, heat fade occurs 

when linings overheat and become less aggressive. Gradual and 

predictable fade is desirable as a warning. 

Brake Proportioning - Optional safety-oriented system, often 

called “bobtail proportioning,” for limiting drive axle brakes while 

a tractor is operated without a trailer. Also, system that varies 

individual axle braking effort in response to weight or other 

variable. 

Brake Treadle - Functionally, the brake pedal - a mechanical 

lever attached to the foot brake valve. 

Breakaway Valve - Upon accidental separation of trailer(s), a 

tractor protection system that prevents air loss from the power 

unit. See “Tractor Protection Valve.” 

Breather - A vent in the drive axle housing for relieving internal 

pressure due to heating and cooling within the housing. 

Bridge Formula - See “Federal Bridge Formula.” 

Broached Bushing - Bushing that is finished by a round cutting 

tool that has multiple teeth each removing a small portion of the 

bushing material to achieve desired finished size. 

B/S-B/S - See “Bearing Shoulder to Bearing Shoulder 

Dimension.” 

Burnish - The conditioning or “seasoning” of a brake lining 

by wear and temperature via a test procedure or in-service 

operation. 

Caliper - In an air disc brake system, the clamping device 

containing friction material mounted to pads. When actuated, 

the caliper applies braking force to both sides of the rotor. 

Camber - The tilt of the wheel side-to-side while looking from 

the front - places the road contact points closer to the king pin 

axis, thereby reducing road inputs to the steering system and 

contributes to steering stability. 

Camber, Negative - Top of the wheel tilts inward.

Camber, Positive - Top of the wheel tilts outward. 

Cam Roll-Over - Jargon denoting that an S-cam has traveled 

beyond its designed stopping position during brake application. 

The wheel end must be removed to repair cam roll over. It is 

caused by a combination of excessively worn lining and drum. 

Cam Same/Opposite Drum Rotation - As can be seen in this 

force vector comparison, the direction of the application force 

is different between cam same and cam opposite. In the cam 

same, the cam rotation is in the same direction as drum rotation. 

In the cam opposite, the primary shoe roller is pushed out and 

up, which tends to allow the cam end of the shoe to be pushed 

against the drum instead of the center of the shoe. This allows 

the shoe to energize itself and increases torque output (slightly) 

over a cam same brake. Also in some cases with certain 

combinations of hardware and lining materials, cam opposite 

brakes are noisy. Of course the question comes to mind “why 

have a cam opposite brake if it is a disadvantage?” The answer 

is that some suspension systems do not have enough clearance 

to allow chamber brackets to be mounted in the proper location 

to allow cam same brakes.

Cam Same

Drum Rotation

Cam Opposite

Drum Rotation

Cam Rotation
DAAG2014 March 2014 87

Glossary

Glossary

Cam UH Length - On DAP trailer axles, the length as measured 

from under the brake cam head to the end of the drum. 

Cardan Universal Joint - A non-constant universal joint 

consisting of two yokes joined by a cross. 

Carrier - Portion of the axle assembly that contains the drive 

gears and differential. 

Caster - Tilt of the kingpin centerline looking from the side - 

offers directional stability and assists in returning wheels to a 

straightahead position through self-centering action. 

Caster, Negative - Kingpin centerline projected behind the road 

contact point. 

Caster, Positive - Kingpin centerline projected ahead of the road 

contact point. 

Central Tire Inflation System - See “CTIS.” 

Channel, ABS - The number of channels in an ABS system 

refers to the number of valves its Electronic Control Unit (ECU) 

is capable of independently controlling. 

1-Channel ABS - A system design that uses two-wheel speed 

sensors and one control valve (2S/1M). This is the most popular 

system for most trailers. It is called tandem control. 

2-Channel ABS - A system design that uses two- or four-wheel 

speed sensors and two control valves (2S/2M or 4S/2M). The 

ABS monitors wheel speed and avoids wheel lockup on one axle 

while braking on low-friction surfaces or in emergency situations 

by rapidly cycling the brakes on the wheel ends of two axles. 

Commonly used on trailers. 

4-Channel ABS - A system design that uses four-wheel speed 

sensors and four ABS control valves (4S/4M) on a two-axle truck 

or tractor. A 4-channel system can also be used on a three-axle 

vehicle, controlling the left and right side drive axle wheels in 

pairs. This popular system, which offers an optimum blend of 

performance and economy, is the most common system on 

trucks, tractors and buses. 

6-Channel ABS - A system design that features six-wheel 

speed sensors and six ABS control valves (6S/6M) to individually 

monitor and control all six wheels of a three-axle truck or tractor. 

This type of system provides the highest available level of ABS 

control. It’s commonly used on vehicles with lift or tag axles. 

Check Valve - A one-way check valve is used, for example, to 

prevent air from bleeding back out of a reservoir. A two-way 

check valve activates selectively, for instance, by drawing air 

for brake application from the most highly pressurized reservoir 

(primary or secondary). 

Clearance Sensing Brake Adjuster - Senses force when brake 

lining contacts the drum to adjust lining to drum clearance. 

Clevis Pin - Pin connecting the arm of a slack adjuster to a brake 

chamber push rod yoke. 

CMVSS 121 (Canadian Motor Vehicle Safety Standard 121) - 

Standard for air brake vehicles. 

Combination - Truck coupled to one or more trailers. 

Combination Lining Block - Two different lining materials on 

the same brake shoe. The higher friction material is on the cam 

end of the brake shoe with the lower friction material on the 

anchor end.

Companion Flange - Drive shaft side of the joint that connects 

the drive shaft to the drive axle. 

Compressible Inserts - Foam inserts installed in the top and 

bottom of the kingpin under the cap that reduce the pressure / 

vacuum that is found in the bushing area during typical service. 

Connectors, ABS - Sealed, corrosion-resistant plugs that link 

the ABS wiring system to the Electronic Control Unit (ECU), wheel 

speed sensors and modulator or relay valves using a shielded 

wiring harness. 

Control Algorithm - The computer commands programmed into 

the Electronic Control Unit (ECU) to control brake actuation under 

impending wheel lockup. 

Controlled Traction Differential - A differential assembly 

that incorporates a friction plate assembly whose purpose is to 

transfer torque from the slipping wheel to the one with traction. 

This assembly consists of a multiple-disc clutch that is designed 

to slip when a predetermined torque value is reached. 

Cracked Drum - Brake drum cracked all the way through by 

excessive heat build-up (perhaps signifying inadequate drum 

weight, and/or driver abuse and/or resurfacing of a drum beyond 

the manufacturer’s limit). It could also be caused by poor brake 

balance. (See “Brake Balance.”) 

Crack Pressure - Minimum air pressure, expressed in pounds 

per square inch (psi), required to open an air valve. 

Cramp Angle - Maximum turn of steering wheel in either 

direction. 

Creep Rating - Extremely slow operation (<1.0 mi/hr) typically 

applying to crane service. 

Cross Link - Composed of the adjustable cross tube and 

threaded tie rod ends with ball sockets that connect the LH 

knuckle tie rod arm to the RH knuckle tie rod arm. 

Cross Tube - Center tube portion of a cross link assembly that 

is threaded with opposite threads on each end, thereby allowing 

adjustment by turning the tube with one hand. 

CTIS (Central Tire Inflation System) - A means of easily 

adjusting the vehicle tire pressure, both inflate and deflate, 

for the conditions encountered whereby improving vehicle 

mobility performance. CTIS is synonymous with military 

off-road applications. 
88 DAAG2014 March 2014

Glossary

DAP (Double Anchor Pin) - Brake system using two pivot pins 

as opposed to just one for anchoring the brake shoes. 

Diagnostics, ABS - A component-by-component selfcheck performed each time the truck’s ignition is turned 

on. An independent microprocessor also checks the system 

continuously during vehicle operation. 

Diagonal System, ABS - A brake system design that divides 

the ABS into two circuits (front wheel on one side with rear on 

the other side, and vice versa) to allow partial system function 

should one diagonal malfunction. 

Differential - Rear axle gear assembly permitting one axle shaft 

and wheel to turn more slowly or faster than the other when 

negotiating a turn.

Differential Lock - A mechanism that eliminates the action of 

the differential so that both wheels can be driven to improve 

tractive efforts on slippery surfaces. See “Driver-Controlled 

Wheel Differential Lock.” 

Digital Processing, ABS - The latest processing technology that 

is many times faster and more reliable than analog processing. 

Disc Brake - A foundation brake system consisting of a flat 

disc or rotor on either side, which are friction pads. Equal and 

opposite forces are applied to these pads to press their working 

surfaces into contact with the braking path of the rotor. 

Dolly - Two-wheel trailer equipped with drawbar and the lower 

portion of a fifth wheel and other components necessary to 

permit a semi-trailer and dolly combination to operate a full 

trailer; sometimes called a “pup.” 

Double Anchor Pin - See “DAP.” 

Double Diaphragm Air Chamber - Generates force output by 

utilizing two separate diaphragms, one in the service chamber 

and the other inside the spring chamber. Double diaphragm brake 

chambers are the most common in North America for general 

truck/tractor and trailer applications. (See “Spring Brake.”) 

Double Drop - Beam having a drop in the center between the 

spring mounting pads, as well as the drop from the KPI to the 

spring mounting pads.

Double Reduction - Dual gear reduction generally used 

in rear axles.

Draglink - Connection between the pitman arm and the steer 

ball on the steer arm. Acts as a pull-and-push rod to convey 

steering movements from the chassis-mounted steering box 

to the spring-mounted axle.

Drain Valve - Used to drain oil and water from air reservoirs. 

Valve may be manual or automatic in operation. Automatic 

versions, which may be heated electrically to prevent the valve 

from freezing open, often are referred to as spitter valves. 

Draw Key - Fastener in the steer axle that works like a wedge 

and provides a mechanism to lock the beam to the kingpin while 

allowing rotation of the knuckle on the kingpin. 

Driver-Controlled Wheel Differential Lock - Driver-controlled 

traction device that can be operated from the vehicle cab 

by a switch. During periods of good traction, the differential 

lock should not be engaged. When locked, power transfer will 

be through the locked differential casing, gearing, and axle 

halfshafts together. This provides maximum traction to both 

sides, prevents “spinout,” and protects against gearing damage. 

Driving Axles, Steerable - Heavy-duty on- and off-road vehicles 

of 4x4 or 6x6 wheel configuration often require traction and 

maneuverability that can only be obtained with a steerable front 

drive axle. 

Drop-In Unit - Generally refers to rear axle gear assembly 

located in axle housing by drop-in. 

Drop Socket - Socket with the ball center not coincident with 

the threaded end. 

Drum Brake - A brake system in which two brake shoes with 

friction material expand into a rotating drum. 

Dry Park Maneuver - Turning steering wheel/tires without any 

forward or reverse movement. 

Dual Drive Axle - See “Tandem Drive Axle.” 

Dual Brake System - A redundant air system (primary and 

secondary) designed to retain braking ability in the event one 

system fails. 

Dual Draw Key - Arrangement of two draw keys used to balance 

load on kingpin to maintain alignment of kingpin to knuckle beam 

bore. (See “Draw Key.”) 

Dual Range - Two-speed, shiftable drive axles that provide two 

gearing ratios: a low range for slow speed hauling off-highway 

and a high range for cruising speeds on-highway. 

Dump Body - A large truck’s metal body that is generally hinged 

at the rear and dumped by hydraulic means. The size is generally 

given in cubic yard water level capacity. 

Duplex Gauge - Essentially, a diagnostic device incorporating 

two separate air gauges with a common housing and utilizing 

indicator needles of different colors. Device is used to diagnose 

brake system imbalance within a combination vehicle via 

simultaneous connection to two points (such as the tractor 

glad-hand and a trailer brake chamber). It’s also used as a 

dash gauge for dual reservoirs. 

Dust Shield - Plate made of metal or polyethylene that is 

mounted behind a brake drum to minimize entry of dirt and 

road splash. 
DAAG2014 March 2014 89

Glossary

Glossary

Duty Cycle - Measurement of the amount of time a component 

is fully utilized, expressed as a percentage of the complete usage 

of the component.

Duty Cycle “Class Definitions” 

AA Turnpike or Interstate - Operation on limited access, 

well-maintained, multi-lane highways of excellent concrete 

or asphalt with maximum adverse grades not in excess of 

3 percent. 

A On-Highway - Exclusive of operation on well-maintained 

major highways of excellent concrete or asphalt construction. 

Terrain may be level to rolling with occasional maximum 

adverse grades to 8 percent. Operations are subject to legal 

weight and dimensional limitations. 

B On-/Off-Highway or Mountainous Highway - Secondary 

roads of good concrete or asphalt where intermittent grades 

of up to 12 percent adverse may be encountered or where 

up to 20 percent of the total operating time is spent on 

well-maintained, off-highway roadways of crushed rock or 

similar material. Grades in this class are more frequent and 

severe than in Class A operation. Operation is subject to legal 

weight and dimensional limitations. 

C Off-Highway - Operation exceeding 20 percent of the time 

on roads of gravel or maintained crushed rock surface 

where the maximum grade is 12 percent and frequent grades 

of 8 percent can be encountered. This operation is not 

generally subject to legal weight or dimensional limitations. 

D Off-Road - Exclusively off-highway on private roadways with 

partial operation off-road in areas with no maintained hard 

surface. Grades and surface conditions may be variable. 

Operation is not subject to legal weight or dimensional 

limitations. 

EBS - The abbreviation for Electronic Braking System, or 

brake-by-wire. A system in which the control signal is sent 

electronically, rather than pneumatically, although the actual 

service application is still made by air pressure. 

ECE 13 - Uniform provisions concerning the approval of vehicles 

with regard to braking in Europe. 

ECU, ABS - The abbreviation for Electric Control Unit, is a 

microprocessor that evaluates how fast a wheel is rotating. 

The electrical signals generated by the inductive sensors pick up 

impulses from toothed rings that spin with the wheel. It is part of 

an Anti-lock Brake System. 

Edge Codes - Developed by Friction Materials Standards 

Institute, a double letter code (e.g., EE, FF, GG, FG) printed on 

the edge of a brake block to designate its range of friction in 

cold and hot test conditions. 

EEC - On the approximation of the laws of the member states 

relating to the braking devices of certain categories of motor 

vehicles and their trailers. Published in the official journal of 

European Economic Communities. 

Emergency Brake System - Not a separate system, emergency 

braking (in the event of air loss) involves various portions of the 

parking and service brake systems. See “Spring Brake.” 

End Play - Looseness in bearing clearance in an axial direction. 

End Yoke - Connects the drive shaft to other driveline 

components. 

Engine Brake - A system that allows for slowing of a vehicle 

that is independent of the conventional braking systems. A 

driver would normally downshift to slow his descent on a hill, 

using engine compression. The engine brake increases the 

effectiveness of this retarding force. 

Exhaust Brake - Brake device using engine compression 

pressure as a retarding medium. 

Fail-Safe, ABS - If the antilock brake system should fail 

during vehicle operation, a dash light warns the driver that 

ABS is disengaged. Meanwhile, the tractor’s pneumatic system 

returns to normal relay valve functions and maintains standard 

air brake performance. 

Fault Codes, ABS - A series of codes displayed by the selfdiagnostic portion of the ABS unit, isolating the section of the 

system that is now or has malfunctioned. 

FC - Fast Change style brake shoes, with standard thickness 

lining. 

FC XLII - Fast Change style brake shoes, with extra thick lining. 

Federal Bridge Formula - Formula that limits the weight on 

groups of axles in order to reduce the risk of damage to highway 

bridges. Allowable weight depends on the number of axles a 

vehicle has and the distance between those axles. However, the 

single or tandem axle weight limits supersede the Bridge Formula 

limits for all axles not more than 96 in. apart. 

FMSI - An industry standard number assigned to a brake shoe 

lining. All shoe linings that have the same FMSI number should 

dimensionally be the same regardless of brand. 

FMVSS 121 (Federal Motor Vehicle Safety Standard 121) - 

Performance Standard for air-braked vehicles. 

Foam Insert - Foam piece also known as the compressible 

insert. 

Foot Valve - A foot-operated valve controlling air pressure 

delivered to the brake chambers. 

Force Balance - Optimum stopping capability requires tire-toroad retarding forces in proportion to the loads on all wheels. 

Foundation Brake Balance - Foundation brake balance deals 

with the brake itself (not including the air system), brake lining, 

tire size, air chamber, slack length, etc. Can be separated into 

two different aspects, torque balance and thermal balance, 

between different axles. 
90 DAAG2014 March 2014

Glossary

Foundation Brake System - Term inclusive of mechanical 

components involved in providing braking force (i.e., brake 

chambers, slack adjusters, brake drums, rotors, and brake 

linings) on a vehicle. 

Four Bag Suspension - A single axle air ride suspension 

with four air springs, usually located at each corner of the 

suspension structure. The suspension moves up and down 

as a parallelogram design. 

Frame (Disc Brake) - Structural element which supports caliper 

and mounts brake assembly to torque plate. 

Friction Couple - Refers to the lining and drum combination 

used to convert kinetic energy to heat energy. 

Front Axle Limiting Valve - See “Ratio Limiting Valve.” 

FT - A fabricated brake shoe comprised of a stamped shoe table 

and webs welded together. 

Full-Floating Axle - Axle shaft transmits torque and the axle 

housing supports the vehicle ground load. 

GAW (Gross Axle Weight) - Total weight on a specific axle 

position. 

GAWR (Gross Axle Weight Rating) - The total weight capacity 

of an axle (single, tandem, or tridem). 

GCW (Gross Combination Weight) - The weight of a truck and 

trailer combination and its entire contents. 

GCWR (Gross Combination Weight Rating) - The total weight 

capacity of a truck and trailer combination and its entire contents 

as determined by axle ratings. 

Gear Ratio, Axle - Ratio of the speed of the propeller shaft to 

the speed of the rear axle shaft. 

Glad-Hand - A separable mechanical connector used to join air 

line hoses when combination vehicles are coupled together. 

Grade - The degree of inclination of a road. Typically specified 

in percent (rise/100 ft run). 

Gradeability - Percent grade that a vehicle will negotiate. 

Grease-Stained Drum - A brake drum with discoloration of 

friction surface caused by, for example, improper greasing of 

brake camshaft or wheel seal leakage. 

Gusset - A reinforcement welded to the camshaft bracket to 

provide additional support for severe service applications. 

GVW (Gross Vehicle Weight) - The total weight capacity of 

a single vehicle. 

GVWR (Gross Vehicle Weight Rating) - The total weight 

capacity of a single vehicle as determined by axle ratings. 

Hand Valve - See “Trailer Control Valve.” 

Heat-Checked Drum - Brake drum with hairline cracks on 

friction surface caused by thermal cycling. Mild checking 

normally does not require drum replacement. 

Heat-Spotted Drum - Brake drum with a pattern of hard, slightly 

raised dark spots of martinsite on its friction surface. Caused 

by localized overheating and sudden cooling, those spots should 

be ground off to prevent drum cracking, uneven lining wear, and 

loss of braking efficiency. If spots cannot be removed, the drum 

should be discarded. Heat spotting is promoted by light and 

steady braking on downgrades. 

Helper Spring - Additional spring device permitting greater load 

on axle. 

High Articulation Suspension - Type of suspension for off-road 

activity. Greater articulation or suspension travel is required to 

keep tires in contact with the ground. 

High Entry Single - Front tandem axle used as a single axle. 

Highway - A major road used for any form of motor transport, 

typically outside of any city limits and with road surfaces of good 

to excellent concrete or asphalt. 

Hold-Off Spring - A spring within a relay valve or quick 

release valve that is designed to retard valve operation until 

a predetermined amount of air pressure is exerted. See 

“Crack Pressure.” 

Horsepower - English unit used to denote the amount of work 

done in a given period of time, equal to 33,000 foot-pounds 

per minute. 

Housing - A casing or container for mechanical components. 

Housing Box - Cross-section of square-armed or rectangulararmed axle housing. 

Hub Mount Wheel - Wheels that are designed to center on 

the hub at the bore of the wheel. These wheels generally have 

straight-through bolt holes, since the bolt holes only supply 

clearance for the stud. Hub mount wheels are used with twopiece flange nuts. 

Hypoid Gear - Modified Spiral Bevel Gear that allows the pinion 

to be positioned below the ring centerline. 

Hysteresis - Difference between the amount of pressure needed 

to open a valve and the pressure drop needed to close it. 

I-Beam - Forged steel structural beam constructed in the shape 

of an “I.” 

Inertia Excitation - Excitation produced by the oscillating torque 

loads resulting from the driveshaft inertia being accelerated 

through non-uniform motion. 

Inset Wheels (or Negative Offset) - The wheel centerline is 

positioned inboard of the wheel mounting surface. 

Installation Angle - Angle that the drive shaft enters the 

differential relative to horizontal. 

Integral Coach - Designed to carry passengers, the cab and 

body of this style coach are built as one, most often with rear 

engine design. 
DAAG2014 March 2014 91

Glossary

Glossary

Integral Knuckle - One-piece steel knuckle forging made with 

both steer and tie rod arms forged into one piece. 

Interaxle Differential - Gear device dividing power equally 

between axles and compensating for unequal tire diameters. 

Interstate - One of a system of limited access highways 

extending between the major cities of the 48 contiguous 

United States.

Inversion Valve - Valve used on trucks to release air from 

the parking brake chambers and apply the rear brakes if the 

rear air reservoir fails, modulated by the brake pedal. 

Jackknife - Uncontrollable articulation of a tractor-trailer 

typically resulting from lockup or spinning of tractor drive 

axle(s). The risk of jackknife is greatest on a slippery road 

with an empty or lightly laden trailer in tow. 

Jake Brake - Trademark of engine brakes by the Vehicle 

Equipment Division of The Jacobs Manufacturing Co. See 

“Engine Brake.” 

Jam Nut - Second nut on a screw or bolt that locks against the 

first nut (i.e., jams against it) so that the nut won’t come loose. 

Kingpin - Front axle pin allowing wheels to steer vehicle. Also 

called knuckle pin. 

Kingpin Angle - Angle of the kingpin in relation to a vertical 

line at the point of intersection on the ground at tire contact as 

viewed from the front or back. 

Kingpin Cap - Bolt-on or threaded-in cap used to seal the 

outer sides of the upper and lower portion of the steer knuckle. 

This cap is used to prevent contamination from getting into the 

kingpin joint area. 

Knuckle - Integral with the spindle, the inner portion of which is 

affixed to, and pivots on, the kingpin. 

Knuckle Cap - See “Kingpin Cap.” 

Knuckle Pin - See “Kingpin.” 

Knuckle Seal - Seal built into inner side of the upper and 

lower portion of the steer knuckle. This seal is used to prevent 

contamination from entering the areas between the kingpin, the 

knuckle, and the beam. 

KPI (Kingpin Intersection) - The distance between the 

intersection points of LH and RH steer knuckles pivot, or the 

points where the spindle axis crosses the kingpin axis. 

Leak-Down Test - A common method of checking for air 

leaks. With the engine off, vehicle stationary, the air system at 

maximum governed pressure and all service brakes fully applied, 

there should be no more than a 3 psi/min. air loss noted on the 

dash-mounted pressure gauge for straight trucks; 4 psi/min. for 

combination vehicles. 

Liftable Axle - Axle that is capable of lifting off the ground and 

reducing load during parking maneuvers and lowering to the 

ground and reducing the load from bridge laws. See “Pusher 

Axle” and “Tag Axle.” 

Limited Access - Roads where access is controlled and limited 

to entrance and exit in designated areas such as highway ramps. 

See “Turnpike.” 

Limited-Slip Differential - Mechanical action that resists the 

free working of an ordinary differential, thus distributing a greater 

torque to the slower-turning wheel or axle. 

Linehaul - Trucking involving moving different types of freight in 

high mileage operation (over 60,000 miles/year). 

Lining Swell - Temporary swell of brake lining that occurs with 

heat, but returns to original when cooled. 

Lining Growth - Permanent swelling of brake lining resulting 

from heat exposure. Occurs in new lining only. 

LMS®

 (Low Maintenance System) - Optional packages are 

either lube for life or annual lube. 

Locator Dowel Hole - Drilled hole located centrally on the spring 

pad drilling that is used to locate the caster block used to attach 

the springs to the steer axle. 

Lockout Assembly - A shift unit that controls the operation of 

the interaxle differential in tandem drive axles. The operation of 

this unit is controlled from the vehicle cab by the driver and is 

activated by either air pressure from the vehicle’s air reservoir 

(brakes) or by electrical means.

Long-Stroke Chamber - A brake chamber designed to have 

longer-than-normal push rod travel, adding safety factor to 

chamber stroke. For example, a regular, clamp-type, Type 30 

chamber has a readjustment limit of 2 in. and a maximum 

stroke of 2.5 in. A Long has a readjustment limit of 2.5 in. 

and a maximum stroke of 3 in. 

Low Maintenance System - See “LMS®.” 

Low Pressure Warning Device - Pressure-sensitive electrical 

switch that actuates an in-cab buzzer and warning light when air 

pressure falls below a predetermined level (typically, 60 psi). 

Marion Support - A “tear-drop” shaped support that fits over 

the camshaft barrel located between the chamber bracket and 

the automatic brake adjuster (ABA). The Marion Support is 

welded to the axle housing after the brake assembly is mounted 

to the axle. This is an optional means of support where the BCCC 

dimension is 13.5 in. or longer. 

Mechanical Suspension - A suspension that is not an air ride 

suspension. 

Michigan Special Gravel Trains - An 11-axle combination 

permitted in Michigan with gross weights as high as 164,000 lbs.
92 DAAG2014 March 2014

Glossary

Multiplexing - A means of sending discreet electrical signals to 

multiple devices along a common pair of wires. 

Neutral Engagement Valve - A component of the pneumatic 

system that permits the service brake to be applied when 

the transmission is in neutral and the driver is out of the cab. 

Typically found on refuse trucks. 

NoSPIN®- Speed-sensitive automatic locking differential. 

It powers both drive wheels while automatically permitting 

differential action to compensate for wheel speed differences 

from turning or driving on uneven surfaces. 

OAW (Overall Width) - Width across the widest portion of the 

vehicle/axle/etc. 

OEM (Original Equipment Manufacturer) - Company that first 

created the product. 

Off-Highway - Refers to trucking usually performed on private 

logging roads, construction sites, mining locations, etc. Offhighway trucks are always constructed much more ruggedly 

as they are subjected to severe stresses. 

On-Highway - Refers to trucking performed on turnpike quality 

roads, freeways or expressways. 

On-/Off-Highway - Refers to trucking operations that involve 

traveling both on highways and on roads of lesser standards; 

typical of this is timber haulage wherein logs are hauled on forest 

tracks or roads, and then on the highway to a mill or rail sliding. 

Also livestock haulage when the loading point is some distance 

along a rough road, and the load is then moved to abattoirs or 

elsewhere on a highway or similar road. 

Original Equipment Manufacturer - See “OEM.” 

Out-of-Round Drum - Brake drum with variations in its inner 

diameter, causing reduced braking efficiency. An out-of-round 

drum often can be machined, within manufacturer’s limits, to 

restore concentricity. 

Outset Wheel - Wheel with a centerline of the tire outboard of 

the wheel mounting surface. 

Overall Width - See “OAW.” 

Overhang - The distance from the center of the leaf spring or 

air suspension bracket to the centerline of the tire/tires. 

Oversized Drum - Refers to a brake drum having an inner 

diameter greater than the discard diameter marked on the drum 

by its manufacturer. 

Parallelogram Suspension - A suspension with four trailing 

arms that allow the axle to travel in a linear motion without 

caster change. 

Parking Brake - See “Spring Brake.” 

Parking Brake Priority - A type of trailer brake control valve 

that prioritizes delivery of air for quick release of a trailer’s 

parking brakes after being hooked to a tractor. Charging a 

trailer’s service reservoirs, to provide braking ability, is a 

secondary concern. 

Pawl - A mechanical device allowing rotation in only one 

direction. One type consists of a hinged tongue, the tip of 

which engages the notches of a cogwheel, preventing 

backward motion. 

Payload - Actual weight of useful cargo carried by the vehicle. 

Piston Type Chamber - Incorporates a piston in place of the 

diaphragm inside the spring chamber. This chamber will provide 

approximately 30% to 40% higher pushrod output for parking. 

The service chamber, however, still utilizes a diaphragm. Piston 

type chambers are more common in Europe and also for transit 

buses in North America. 

Pitman Arm - Arm attached between the steering gear sector 

shaft and the draglink that transmits the steering force from the 

cross shaft to the steering linkage system. This is how the rotary 

motion of the steering wheel is turned into lateral movement of 

the arm. 

Planetary Double Reduction Axle - The double reduction 

axle provides greater overall gear reduction and is ideal for 

peak torque development and transmission. This feature makes 

the axle desirable for starting heavy loads in adverse terrain. 

The first reduction is through the primary gearing. The second 

reduction is with adjacent planetary gearing. 

Planetary Gears - A gearing unit consisting of a ring gear 

with internal teeth, a sun or central pinion gear with external 

teeth, and a series of planet gears that mesh with both the ring 

and the sun gear. Frequently used in overdrives and automatic 

transmission. Also called epicyclic gearbox. 

PLC (Power Line Carrier) - A form of multiplexing wherein a 

discreet electrical signal is sent along a wire already carrying 

power for another purpose. PLC technology is used in tractor/

trailer communications, allowing more utility than the standard, 

J-560, 7-pin connector could otherwise afford. 

Pneumatic Balance - Achieved when individual air chambers 

receive the air pressure required for each brake in the system 

to do its fair share of the work. Lack of pneumatic balance is 

most likely at low brake application pressures, rarely during 

panic stops. 

Pneumatic Timing Balance - Achieved when individual air 

chambers sequentially receive air within a timeframe that 

ensures each brake in the system will do its fair share of the 

work. In a combination vehicle, lack of proper timing is likely 

to occur because tractor brakes receive air faster than trailer 

brakes. See “Trailer Push.” 

Pole Trailer - Trailer used to transport utility poles. 

Polished Drums - A brake drum with a friction surface polished 

to a mirror-like finish by unsuitable brake linings. Remove gloss 

from drum with 80-grit emery cloth. 

Pop-Off Valve - Jargon for a pressure-relief valve, installed 

in the service reservoir or wet tanks as insurance against 

over-pressurization. 
DAAG2014 March 2014 93

Glossary

Glossary

Power Divider - See “Interaxle Differential.” 

Power Line Carrier - See “PLC.” 

Pressure Differential - Difference between the inlet and outlet 

air pressure of an open brake valve. Also, difference in air 

pressure between any two points within a brake system. 

Pressure Level Balance - Obtained when all of the vehicles’ 

brake chambers are receiving the required level of air pressure 

(once pressures have stabilized). This does not necessarily mean 

the same pressure. Different design brakes on the same vehicle 

may require different levels of air pressure. Pressures may be 

varied on different axles to compensate for different size brakes 

or different amount of underbody cooling received by the brakes. 

Propeller Shaft - Driveshaft used to transmit torque from engine 

or transmission to rear axle. 

Pumping the Brakes - Phrase denoting a rapid series of brake 

application (a.k.a. fanning) used to avoid locking brakes on 

axles during sudden stops. Phrase also may apply to a slower 

series of heavy brake application (a.k.a. snubbing) used in an 

attempt to prevent brake overheating and resultant fade on long 

downgrades. 

Pup - See “Dolly.” 

Pusher Axle - A “dead axle” (no driving capability) used to give 

vehicle more weight carrying capacity. A pusher axle is ahead 

of the drive axle. A tag axle is behind the drive axle. This type of 

axle may have the capability of being raised or lowered and some 

are made to be steerable. 

Push Rod - A rod, protruding from a brake chamber, that is 

connected to the arm of a slack adjuster via a clevis pin. 

Quick-Release Valve - Designed to reduce the chance of brake 

drag, a valve that speeds the process of exhausting air from 

brake chambers when driver releases the brake treadle. 

Radio Frequency Interference - See “RFI.” 

Ratio Limiting Valve - Prevents locking of front brakes by 

automatically limiting application pressure to steer axle during 

normal braking. Progressively harder braking, however, will 

progressively increase steer axle braking until maximum air 

pressure is applied. 

Regional Haul - On-highway usage within a region, typically a 

one-day round trip. 

Relay Valve - Valve located near a reservoir that is activated by a 

control signal from another valve that usually is farther away. It is 

used to speed the application of brakes on drive and trailer axles. 

Release Time - Time between release of brake treadle and 

total disengagement of brake linings and brake drums. Or, per 

FMVSS-121, the time required to reduce pressure to 5 psi from 

95 psi within all service chambers. 

Relief Pressure - Maximum pressure where the steering gear is 

protected from providing too much load into the steering system. 

Retarder - Auxiliary speed-reducing device. 

Return Springs - Springs that retract brake shoes upon release 

of the brake treadle. 

Reverse Cam Rotation - When the axle is installed into the 

vehicle in such a way that the brake cam rotates opposite to 

the forward normal turning direction of the tire. 

RFI (Radio Frequency Interference) - External interference 

or false signals from such sources as radar, citizens-band radio, 

other types of radio transmissions and television signals. While 

the effects of this interference on ABS were a concern during the 

1970’s, today’s technology has virtually eliminated the problem. 

Ring Gear - The large bevel, circular gear that is attached to the 

flange or carrier of the differential case. It meshes with the drive 

pinion on the end of the propeller shaft. 

Rolled Over - Axle used when engine is located behind axle; 

typically the pinion will be above the centerline. 

Rolling Resistance - Sum of the forces at area of contact 

between a vehicle’s tires and road surface acting against the 

direction of movement.

Roll-Off Containers - Detachable open containers generally 

used for hauling refuse, scrap, and construction debris that 

are hoisted or winched over the rear of the truck chassis for 

transport. 

Rotor - Braking surface for disc brake system. On heavy trucks 

the rotor is generally cast iron and has vented design. The rotor 

can be either separate or integral to the hub. Rotors are also 

referred to as discs. 

SAE (Society of Automotive Engineers) - An international 

organization of automotive/truck/bus engineers who develop 

test procedures and requirements for all ground transportation 

vehicles and their components. 

SAP - Single anchor pin-type brakes. 

S-cam Brake - Type of brake where mechanically induced 

rotation of an S-shaped cam forces brake linings against the 

brake drum. 

Scored Drum - Brake drum with a grooved friction surface, 

resulting in excessive lining wear. Severe scoring requires that a 

drum be machined, within manufacturer’s limits, before replacing 

the linings. 

Secondary - Roads that are typically well-maintained gravel 

or crushed rock; surface conditions are not as favorable as on 

primary roads. 

Semi-Active Suspension - A suspension that changes its ride 

quality in response to hitting a bump or alteration in the road. 

This change must occur in milliseconds to be effective. 

Semi-Trailer - Trailer used in connection with truck tractor. 

Sensor Sleeve - Rigid steel sleeve mounted in the knuckle 

to provide a pilot for the ABS sensor to be mounted in close 

proximity to the tone ring on the hub. 
94 DAAG2014 March 2014

Glossary

Service Brake Priority - A type of trailer brake control valve 

that prioritizes delivery of air to a trailer’s service reservoirs, to 

provide braking ability, after being hooked to a tractor. Releasing 

a trailer’s parking brakes is a secondary concern. 

Service Brake - As opposed to spring or parking brakes, that 

portion of the brake system used for normal brake application 

while driving. 

Shift Inhibitor - Pneumatic-mechanical system that delays the 

shifting process until the engine has returned to idle speed. This 

prevents drivetrain damage due to high RPM shifting. 

Shims - Spacers used to fill in the space between knuckle and 

top of beam after thrust washer is installed on the bottom side 

of the beam. 

Single-Reduction Axle - Any axle assembly with only one gear 

reduction through its differential ring gear and drive pinion. 

Site Travel - Slow speed operation up to 5 mph at a job site not 

to exceed 5% of total operating miles of the vehicle. 

Slack Adjuster - Also called a brake adjuster, this is a lever 

connecting the brake chamber push rod with the foundation 

brake camshaft. It provides torque to rotate the brake camshaft 

when the brake treadle is depressed. It also provides a means 

of adjusting clearance between brake shoes and the drum to 

compensate for lining wear. Some models are automatic while 

others require manual adjustment. See “ABA.” 

Slip Torque - Engine torque required to slip wheels on the 

driving surface. 

SLR (Static Loaded Radius) - The distance from the centerline 

of the axle to the ground, underrated tire capacity, with the tire 

at rest.

SMC (Suspension Mounting Centers) - The distance between 

centerlines of where the suspension clamps to the axle.

Soft Dampened Clutch - Special type of clutch that features a 

torsional mechanism that avoids impact loads being transmitted 

through the driveline. 

Speed Sensor, ABS - An electromagnetic device that, in 

conjunction with a rotating toothed wheel, generates an 

electrical signal proportional to the wheel speed and transmits 

the information to the ABS Electronic Control Unit (ECU). 

Spider - Spider-like casting or forging containing axle differential 

or the foundation brake structural member. 

Spindle - A shaft-like projection from the steering knuckle or 

the drive axle housing to which the wheel is mounted. 

Spinout - When the maximum drive slip resistance has been 

exceeded by its tractive effort and a sudden increase in drive 

wheel speed occurs. 

Spiral Bevel Gear - The teeth of both the ring and the pinion are 

tapered and are cut on a spiral so that they are at an angle to the 

centerline of the pinion shaft. 

Spitter Valve - Slang for automatic drain valve. 

Spline - Series of parallel keys cut along the driveshaft that mate 

with corresponding slots in hub or fitting. Also found on brake 

camshaft interface to slack adjuster. 

Split-Coefficient Surface - Also called split-Mu, a road 

condition where one side of a lane has low friction and the other 

has high friction (for example, the left side of the lane is ice 

covered, the right side is dry). A 2-, 4-, or 6-channel ABS system 

(anti-lock brake system) with individual wheel control will provide 

optimum stability and stopping-distance performance under 

these conditions. 

Spring Brake - Generally refers to a tandem-chamber brake 

actuator that incorporates an air-applied service brake chamber 

and an air-release/spring-applied parking or emergency brake 

chamber. Spring brakes apply upon sudden air loss (emergency 

mode) or activation of a dash-mounted parking brake control. 

Spring brakes remain applied until that chamber is recharged 

with air or the spring is manually compressed or caged. The 

spring portion is often referred to as the “piggyback.” Spring 

brakes generally come in two types: double diaphragm or piston. 

 

DISASSEMBLY OF A SPRING BRAKE IS 

DANGEROUS. ONLY TRAINED MECHANICS 

SHOULD ATTEMPT THE PROCEDURE.

Spring Mounting Centers - See “SMC.” 

Spring Pad - Flat locator surface on the beam that is drilled for 

the specific mounting pattern for the U-bolt connection to the 

leaf spring. 

Static Loaded Radius - See “SLR.” 

Steerable Drive Axles - See “Driving Axles, Steerable.” 

Steer Arm - Rigid connection between the steering mechanism 

and the steer knuckle. 

Steer Arm Ball Stud - Tapered round ball mounted in the 

steer arm providing a means of articulation when the draglink 

transmits steering motion from the steering gear, that is 

mounted on the frame to the steer axle which is mounted 

as part of the suspension. 

Steer Arm Swing Radius - Radius created when the steer 

knuckle rotates from stop to stop; establishes clearance window. 

Steering Gear - The mechanism that translates the steering 

wheel rotation into movement at the steer knuckle through 

the draglink. 

Steering Knuckle - The inner portion of the spindle that is 

connected to, and pivots on, the kingpin allowing the wheels to 

turn while under load. 
DAAG2014 March 2014 95

Glossary

Glossary

Stopping Distance - The distance traveled by a vehicle on a 

road between the initial brake pedal movement and a full stop. 

Stopping Time - The time elapsed between the initial brake 

pedal movement and a full stop. 

Stop Screw - A combination screw and lock nut arrangement 

that limits the angular travel of the steer knuckle in a steer axle. 

Straight Truck - A non-articulated vehicle that carries cargo in 

a body mounted to its chassis, rather than on a trailer towed by 

the vehicle. 

Stroke - Refers to a total distance traveled by a brake chamber 

push rod or slack adjuster arm during brake application. 

Stroke Sensing ABA - Excessive stroke caused by lining wear 

raises the actuator rod during brake apply. The spiral serrated 

activator will jump over serrations on the spring-loaded pawl if 

adjustment is required. Actual brake adjustment is made on the 

return stroke. 

Stud Mount Wheels - Wheels that are designed to center on the 

studs of a hub. These wheels have chamfers at the bolt holes into 

which a ball seat or conical nut is installed to center the wheel. 

The center bore of the wheel is only for clearance of the axle end. 

Super Single Tire - Specially designed tire used in lieu of dual 

tires in certain linehaul rigs and local gasoline tankers. Super 

singles can reduce maintenance and/or save hundreds of pounds 

of tire weight when compared to duals. Also known as “Wide 

Base Tire.” 

Supply Air Tank - The air reservoir immediately downstream of 

the air compressor. See “Wet Tank.” 

Suspension - Attaching parts including springs for securing axle 

or axles to chassis frame. 

Suspension Mounting Centers - See “SMC.” 

Swept Area - The total surface area of the drum or rotor of a 

brake that comes in contact with the friction material during one 

revolution of the wheel. In general, the more swept area a brake 

has, the cooler it will operate. 

Tag Axle - A non-driven (dead) axle installed behind the 

drive axle(s) to increase the permissible gross weight and 

consequently, the payload. Also termed “Trailing Axle.” 

Tandem Drive Axle - Two-axle drive combination or dual drive 

axles. 

Taper - Cone-shaped object or form. 

Thermal Balance - Achieved when all brakes are operating at 

the same temperature. If the proper thermal balance is achieved, 

both the tractor and trailer brakes see the same temperature 

throughout any given braking cycle. On some vehicles, steer axle 

brake temperatures should be somewhat below drive brakes to 

avoid aggressiveness and pull. 

Threaded Drum - Brake drum improperly resurfaced on a lathe, 

resulting in a friction surface akin to that of a scored drum. 

Thrust Bearing - These bearings are designed to carry only 

thrust loads. 

Tie Rod Arm - The arm that is rigidly connected to the steer 

knuckle that ties the LH knuckle to the RH knuckle and also sets 

up the steering/Ackermann geometry. 

Tie Rod Arm Angle - The angle formed in the horizontal plane 

between the vertical plane formed by the kingpin intersection/

pivot point and the tie rod arm mounting hole where the tie rod 

end attaches. 

Tie Rod End - Threaded part with a ball socket for articulation 

that attaches in the cross tube for adjustment. Each end is 

threaded the opposite of the other. 

Tie Rod Offset - The distance from the kingpin intersection/

pivot point to the tie rod arm mounting hole where the tie rod end 

attaches in the lateral direction. 

Timing Balance - Achieved when all brake chambers are 

receiving the required air pressure within an appropriate time 

from application. Due to the nature of long vehicle air systems, 

air cannot be expected to arrive at all axles at the exact same 

time. 

Tire Pressure Controls - See “CTIS.” 

Tire Rolling Radius - See “SLR.” 

TMC (The Maintenance Council) - An organization consisting 

of fleet operators, independent truckers, truck manufacturers, 

component manufacturers, government agencies, media, and 

academia whose primary goal is to communicate the latest and 

best vehicle maintenance procedures to the end-users. These 

maintenance procedures are communicated to the trucking 

industry in the form of Recommended Practices (RP). 

TMS (Tire Maintenance System) - Keeps tires properly inflated. 

Toe - The difference between the tire centerline-to-centerline 

distances in the front versus the rear of steer axle tires. 

Toe-In (Positive toe) - Tires are pointing in as seen from the 

front; provides straight-line directional stability. 

Toe-Out (Negative Toe) - Tires are pointing out as seen from 

the front; will result in “road wander.” 

Top Mount Suspension - A trailing arm suspension in which 

the trailing arm is mounted to the top of the axle. 

Torque Balance - Achieved when individual brakes exert the 

degree of braking force required for each brake in the system to 

do its fair share of the work. 

Torque Converter - A hydraulic drive that transmits power with 

ability to change torque. 
96 DAAG2014 March 2014

Glossary

Torque Plate - A plate used to mount the disc brake caliper to 

the axle brake flange or steer knuckle. 

Torsional Driveline Acceleration - Each universal joint in 

a driveshaft rotates non-uniformly. This non-uniformity is 

minimized or eliminated by the proper relative positioning 

(phasing) of the universal joint yokes at either end of the 

driveshaft. 

Torsional Excitation - Excitation produced by the non-uniform 

velocity obtained when a Cardan joint operates at an angle. 

TPCS (Tire Pressure Control System) - A means of easily 

adjusting the vehicle tire pressure, both inflate and deflate, for 

the conditions encountered whereby improving vehicle mobility 

performance. TPCS is used primarily in the commercial vocation 

market, on-/off-highway. 

Track Width - The distance between the dual tire centerlines 

on a dual tire arrangement or the distance between the tire 

centerlines on a single tire arrangement. 

Tractor - Truck portion of combination or train. 

Tractor Protection Valve - Isolates tractor air system in event 

of a trailer breakaway or dangerous decrease in the tractor’s 

reserve air; typically applied (via dash-mounted control) before 

disconnecting a trailer. 

Trailer Control Valve - Hand-operated valve, located on (or 

adjacent to) the steering column, which permits independent 

control of the trailer brakes; also known as the trolley valve or 

hand valve. 

Trailer Push - Caused by the tractor braking prior to the trailer 

and/or with greater torque. Even with “perfect” brake balance, 

the trailer pushes the tractor to some extent since the tractor 

brakes absorb part of the trailer’s load. 

Trailer Swing - Articulation of the trailer caused by locking the 

trailer brakes. 

Trailing Arm Suspension - A suspension with a total of two 

trailing arms. This suspension forces the axle to travel in an arc, 

which results in a caster change and also torques the axle as 

the suspension goes into roll. 

Trailing Axle - See “Tag Axle.” 

Transfer Case - Split power gear box transmitting drive to front 

and rear axles. 

Transmission (Main) - Selective gearbox providing various 

combinations of gear ratios. 

Transmission (Auxiliary) - Additional gearbox increasing the 

gear ratio combinations when used with main transmission or 

multi-speed axles. 

Treadle Valve - Foot-operated brake actuation valve. 

Tridem Axle - A combination of three axles having a common 

suspension. 

Tri-Drive - See “Tridem Axle.” 

Trolley Valve - See “Trailer Control Valve.” 

Trunnion - Journals allowing pivoting or turning. 

Tubular Beam - Beam constructed of a seamless/hollow tube 

with forged steel beam ends welded on the ends to create the 

foundation of a steer axle. 

Turned Drum - A brake drum that has been resurfaced on a 

lathe to remove scoring or other defects. The diameter must stay 

within manufacturer’s limits. 

Turnpike - Expressway or freeway. 

Two-Speed Axle - A rear-axle assembly that has two different 

output ratios from the differential carrier assembly. Used 

primarily for export and most popular with 5-speed transmissions 

to provide a fast ratio for top speed and a slower ratio for greater 

pulling power. These ratios are controlled by the vehicle driver 

from the cab at the driver’s discretion. This axle is sometimes 

called a dual range unit. 

Two-Spring Suspension - A standard leaf-spring suspension. 

Underslung Suspension - A trailing arm suspension in which 

the trailing arm is mounted to the bottom of the axle. 

Unitized Hub System - Hub system that is factory-filled with 

synthetic grease and sealed to avoid lubrication intervals, bearing 

adjustment, and seal replacement, thereby eliminating hours of 

typical maintenance. 

Vocation - Specific usage of a vehicle in a defined industry. 

Vocational - Dedicated to one specific type of service (i.e., 

mining, oil field, logging etc.). 

Walking Beam Suspension - A mechanical suspension that 

attaches two axles together with the use of a leaf spring or 

structural beam that pivots about a trunnion tube. 

Warning Light, ABS - An indicator light on the truck or tractor 

instrument panel that illuminates to indicate the status of the 

ABS system. On trailer ABS, the indicator light may be located on 

the trailer body where the driver or maintenance personnel can 

easily see it. 

Wedge Brakes - As opposed to a brake applied by an S-cam, 

this type of brake is applied by a single or double wedge-type 

mechanism. This type of brake is self-adjusting and, as such, 

does not utilize an external brake adjuster. 

Wet Tank - Also known as the supply air tank, the reservoir 

nearest to the air compressor where water and oil are most likely 

to accumulate (assuming the lack of a functional air dryer). 

Wheelbase - Distance between centerlines of front steer and 

rear drive axles or to centerline of tandem axles. 

Wheel Bearing - Typically a set of two opposing tapered roller 

bearings that provide radial and thrust load capability while at 

the same time providing rolling motion. 
DAAG2014 March 2014 97

Glossary

Glossary

Wheel Inset, Negative - The rim centerline is positioned inboard 

of the wheel mounting face. 

Wheel Offset - See “Wheel Inset” or “Wheel Outset.” 

Wheel Outset, Positive - The rim centerline is positioned 

outboard of the wheel mounting face. 

Wide Base Tire - See “Super Single Tire.” 

Wide Brake Package - An optional package consisting of 16.5 x 5 

(12K steer) and 16.5 x 8-5/8; (20K/23K drive axle). The greater 

width will reduce brake-operating temperatures thus increasing 

brake life. 

Wide Track - Axle that is wider than standard maximum 96 in. 

overall width. 

Wide Track Housing - Extended-length housing used to meet 

increased track and stability requirements. 

Woodruff Key - A half-moon shaped piece of metal used to 

secure something to a shaft that has a notch cut in the shaft to 

accommodate the key. 

Worm Gear - Component of brake adjuster. The worm and worm 

gear provide for adjusting lining-to-drum clearance. 

Zerk Grease Fittings - Lubrication fitting used for pressurized 

grease application. 

Glossary term sources: 

• Dana Engineering 

• www.1OOmegsfree4.com/dictionary/car-dicm.htm 

• Commercial Carrier Journal with permission to use material 

from “Air Disc Brakes” granted by C. Magner of Randall 

Publishing Co.
Printed in USA DAAG2014 3/14

For spec’ing or service assistance, call 1-877-777-5360 or visit our website at www.dana.com/cv

Dana Commercial Vehicle Products Group

3939 Technology Drive

Maumee, Ohio, USA 43537

www.dana.com/cv

Application Policy

Capacity ratings, features, and specifications vary depending upon the model and type of service. Application approvals must be obtained from Dana; contact your 

representative for application approval. We reserve the right to change or modify our product specifications, configurations, or dimensions at any time without notice.