# Presentation: 818755

## Tire Rolling Resistance for Light Vehicles, I:  Selection of Tires and Tests for Rating System Development

_**John Harris, Transportation Research Center, Inc. **_
**James D. MacIsaac Jr., USDOT - NHTSA**
**Larry Evans, Transportation Research Center, Inc.**
**Presented at ITEC 2008**
**Akron, OH**
**September 17, 2008**

## Tire Rolling Resistance Test Program

**Testing conducted at two laboratories to evaluate lab-to-lab variability:**
- Smithers Scientific Services, Inc. (SSS)
- Akron Rubber Development Labs (ARDL)
- Subcontracted to Standards Testing Labs (STL)
**Five rolling resistance test methods evaluated**
- Three SAE & Two ISO methods
**Twenty five tire models included in study**
- Included Standard Reference Test Tire (SRTT), Tire Type “M14” - ASTM F2493-06, 225/60R16 Tire

## Laboratory Rolling Resistance Testing

***Laboratory Rolling Resistance Testing***

**Smithers Scientific Services, Inc. **
- Force Machine
- All 5 methods

**Standards Testing Labs**
- Torque Machine
- SAE J2452
- Force Machine
- SAE J1269 multi - SAE J1269 single
- ISO 18164    -     ISO 28580

## Selecting a Test Method

**Five Test Methods Evaluated**
- SAE (USA) Rolling Resistance Tests
- J2452 Coastdown
- Auto manufacturers use for vehicle fuel economy calculations over a range of speeds
- J1269 Multi-Point
- Uses four or six sets of test conditions and allows calculation of rolling resistance at a “Standard Reference Condition (SRC)”
- J1269 Single Point
- Runs a single test at the SRC
- ISO (Global) Rolling Resistance Tests
- 18164 Multi-Point
- Four or five rolling resistance values based on four or five test conditions
- 28580 Single Point (Draft International Standard) in ballot
- Runs a single test

## Selecting a Test Method

| Category | SAE J2452
Coastdown | SAE J1269
Multi-Point | SAE J1269
Single Point | ISO 18164 Multi-Point  | ISO 28580 Single Point |
| --- | --- | --- | --- | --- | --- |
| Machine | 1.708 m | 1.708 m | 1.708 m | 1.708 m | >=1.708m |
| Measurement Method | Force,  Torque, or Power | Force,  Torque, or Power | Force,  Torque, or Power | Force,  Torque, Power, or Decel. | Force,  Torque, Power, or Decel. |
| Surface | 80 Grit | 80 Grit | 80 Grit | Smooth Surface (80 grit optional) | Bare or Textured Surface  |
| Speed | Multi | 80 km/h 
(50 mph) | 80 km/h 
(50 mph) | 80 km/h 
(50 mph) | 80 km/h 
(50 mph) |
| Pressure | Multi | Multi | +20 kPa (3 psi) Regulated | Multi
 | 210 kPa - SL capped                    250 kPa - XL capped
100% LT Capped |
| Load
 | Multi | Multi
P 90% & 50% | P 70% sw load | Multi
P 50% & 90%  | P 80% sw load    
LT 85% sw load |
| Reference Temp | 24°C | 24°C | 24°C | 25°C
 | 25°C
 |
| Break-in | 60 min | 30-60 min | 60 min | 30 min | 30 min/50 min |
| Lab Alignment Procedure | No | No | No | No | Yes |

## Overview of 25 Test Tire Models 

## ASTM Standard Reference Test Tire (SRTT)

**ASTM International (American Society for Testing and Materials)**
- Industry and Government consensus standards organization
- www.astm.org
**ASTM Definition: Standard Reference Test Tire**
- SRTT, n.  A tire that is used as a control tire or surface monitoring tire.
**Usage**
- Test Sequence = SRTT, candidate 1, candidate 2, candidate 3, candidate 4,....  SRTT
- Ensures consistency in testing
- Allows rating based on % of SRTT test value

## ASTM Standard Reference Test Tires 

**E 1136**
**P195/75R14**
**Established 1986**
**Currently used for F 1805 Single Wheel Driving Traction (Winter Test for Snowflake Tire) and UTQG**
**FMVSS 139 specifies F 1805 test to determine “winter tire” test criteria**

**F 2493-06****  ****(M14 in this study)**
**P225/60R16 97S**
**Established 2006**
**Designed for use in braking, snow, wear and other performance tests**
**In 28580 tests **
- Coefficient of Variation (C.V.) = 0.9              STD = 0.11 lbs. Mean = 11.8 lbs.

**196 mm**

**231 mm**

**648 mm**

**679 mm**

## Overview of Passenger Tires – Axis #1

**One Manufacturer - Goodyear**
**One Model - Integrity**
- Four Sizes
**+One Run Flat Model**

- G11 P225/60R17 S

- Dunlop Sport 4000 DSST (Run Flat)

- G9   P205/75R14 S

- G10 P205/75R15 S

- G8     225/60R16 S

- U3 P225/60R17 T

## Overview of Passenger Tires - Axis #2

**One Manufacturer – Bridgestone **
**One Size - P225/60R16**
**Six Models**
- Q-W Speed Rating

- B11 Potenza RE-92A H

- B14 Turanza LS-V

- B10 Blizzak REVO 1 Q

- B12 Potenza RE750 W

- B13 Turanza LS-T

- B15 Winterforce S

## Four Manufacturers
One Size - P225/60R16
One Speed Rating - H

**One Size - P225/60R16**
**One Speed Rating - H**

***Overview of Passenger Tires – Axis #3***

- M13 Michelin Pilot MXM4 H

- R4 Pirelli P6 Four Seasons  H

- P5 Pep Boys Touring HR

- D10 Cooper Lifeliner Touring SLE H

## Overview of 16 Passenger Tire Models

- 1 Mfg. - Goodyear
- 4 Sizes
- 1 Model - Integrity
- + 1 Runflat

- 1 Mfg. - Bridgestone
- 1 Size - P225/60R16
- 6 Tire Models

- 4 Mfg.
- 1 Size - P225/60R16
- 1 Speed Rating - H

- G9   P205/75R14 S
- G10 P205/75R15 S
- G8     225/60R16 S
- G11 P225/60R17 S

**M14 Reference  Tire ASTM SRTT S**

- B11 Potenza RE-92A H

- B14 Turanza LS-V

- B10 Blizzak REVO 1 Q

- B12 Potenza RE750 W

- B13 Turanza LS-T

- B15 Winterforce S

- M13 Michelin Pilot MXM4 H

- P5 Pep Boys Touring HR

- D10 Cooper Lifeliner Touring SLE H

- R4 Pirelli P6 Four Seasons  H

- U3 P225/60R17 T

**Axis #2**

**Axis #3**

**Axis #1**

## Overview of 9 Light Truck Tire Models 

- LT235/85R16
- LT245/75R16
- LT265/75R16

- 1 Mfg. - Cooper
- 3 Sizes
- 1 Model - Discoverer ST-C

- 1 Mfg. - Michelin
- 1 Size - LT245/75R16
- 3 Models

- Michelin Radial LT

- Michelin LTX M/S

- Michelin LTX A/S

- 3 Mfg.
- 1 Size - LT245/75R16

- General Ameri*Trac TR

- Kumho Road Venture HT

- PEP Boys Scrambler A/P

**Axis #5**

**Axis #4**

**Axis #6**

## Data Range - Pounds Force & RR Coefficient (10-3)

**Passenger**
**Lbs. = 9.7 – 15.3**
**RRC = 7.3 – 11.6 (x10****-3****)**

**Light Truck**
**Lbs. = 22.0 – 28.4**
**RRC = 8.5 – 11.0 (x10****-3****)**

## Passenger Tire Rolling Resistance as % SRTT

**Axis #1 - Data range from 85.61 to 102.39% of SRTT**
- One Manufacturer - Goodyear
- One Model - Integrity
- Four Sizes
- +One Run Flat Model (116.45%)
**Axis #2 - Data range from 83.97 to 126.34% of SRTT**
- One Manufacturer – Bridgestone
- One Size - P225/60R16
- Six Models
- Q-W Speed Rating
**Axis #3 - Data range from 100.08 to 122.63% of SRTT**
- Four Manufacturers
- One Size - P225/60R16
- One Speed Rating - H

## Light Truck Tire Rolling Resistance as % SRTT

**Axis #5 - Data range from 196.62 to 215.20% of SRTT**
- 1 Mfg. - Cooper
- 3 Sizes
- 1 Model - Discoverer ST-C
**Axis #6 - Data range from 183.31 to 187.93% of SRTT**
- 1 Mfg. - Michelin
- 1 Size - LT245/75R16
- 3 Models
**Axis #7 - Data range from 191.31 to 233.54% of SRTT**
- 3 Mfg.
- 1 Size - LT245/75R16

## Comparison of Single Point Rolling Resistance Tests

**ISO 28580 (Draft)**

**SAE J1269 Single (SRC)**

**1.708m Test Machine**
**Force/Torque/Power methods**
**80 Grit Surface**
**24°C Reference Temperature**
**80 km/h (50 mph)**
**70% sidewall load**
**@ +20 kPa (3 psi) Regulated**
**60 minute break-in ****(optional)**

**1.708m or greater Test Machine**
- Not corrected to 2m in this study
**Force/Torque/Power/Deceleration methods**
**Bare or Textured**** ****Surface **
**25****°C Reference Temperature**
**80 km/h (50 mph)**
**80 Passenger / 80 LT % sidewall load**
**210 kPa Pass / 100% LT pressure**
**Capped**** ****pressure**
**NO**** ****break-in**
**Lab Alignment Procedure**

## ISO 28580 (Draft) vs. SAE J1269 SRC

- Bare surface less accurate at high light truck tire loads
- Not a large database to date

- Regulated pressure is different from highway usage
- Coefficient of Variation was 2.3

**ISO 28580 (Draft)**

**J 1269 Single (SRC)**

***Advantages***

- Harmonization - Being developed by ISO and Tire Industry as “World Standard”
- Least difference in labs studied
- Coefficient of Variation was 1.2

- Tire Industry has large data base of results from this test
- Database from J1269 Multi-Point can be used to calculate SRC result

***Disadvantages***

## ISO 28580 (DIS) Lab Alignment

**Includes 2 “Alignment Tires” for passenger being developed / defined by ETRTO **
**Includes 2 “Alignment Tires” for light truck (C tire) being developed / defined by ETRTO**
**Results corrected to 2 meter drum diameter**
**Uses control tires to handle day-to-day, month-to-month variation, or out of calibration**

## Test Program Summary

**Two laboratories were included in testing**
**Five Test Methods Evaluated**
**Twenty five tire models included in study**
- Passenger tire rolling resistance range:
- Force = 9.7 – 15.3 lbs
- RRC = 7.3 – 11.6 (x10-3)
- %SRTT = 83.97 – 126.34%
- Light truck tire rolling resistance range:
- Force = 22.0 – 28.4 lbs
- RRC = 8.5 – 11.0 (x10-3)
- %SRTT = 183.31 – 233.54%