A11101 lllflDM

NBS

PUBLICATIONS

NBSIR 79-1750(R)

Investigation of the Noise

Generated by "Quiet" Design

Bias-Ply and Radial Truck Tires

With Cross-Bar Tread Patterns

Roger D. Kilmer

National Bureau of Standards

National Engineering Laboratory

Washington, D C 20234

May 1979

Prepared for

QC

100

,156

79-1750

U.S. Department of Transportation

National Highway Traffic Safety Administration

Office of Heavy Duty Vehicle Research

Washington, D.C. 20590

NBSIR 79-1 750(R)

INVESTIGATION OF THE NOISE

GENERATED BY "QUIET" DESIGN

BIAS-PLY AND RADIAL TRUCK TIRES

WITH CROSS-BAR TREAD PATTERNS

Of Stwrfk1**

Katonat IW*'

DEC t 2 '9 ,9

not fvc -<! <SdiCD

W5C=

C,

3—

Roger D. Kilmer

Notional Bureau of Standards

National Engineering Laboratory

Washington, D C. 20234

May 1979

Final Report

Prepared for U.S. Department of Transportation

National Highway Traffic Safety Administration

Office of Heavy Duty Vehicle Research

Washington, D.C. 20590

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS. Ernest Ambler, Director
.
Table of Contents

Page

List of Figures ii

List of Tables iii

Conversion Table to SI Units iv

Abstract v

1. Introduction 1

2. Field Test Program 1

2.1 Field Test Site 1

2.2 Test Tires 2 2.3 Test Vehicle 12

2.4 Test Procedure 12

3. Test Results 16

3.1 Comparison of Results with Existing Data

for Bias-Ply Cross-Bar Tires 22

3.2 Effect of Pavement Surface 25

3.3 Effect of Tread Wear 27

3.4 Conclusions 30

4. Appendix A. SAE Recommended Practice for Measurement

of Truck Tire Noise 32

5. References 34

6. Acknowledgements 36
List of Figures

Page

Figure 1. Plan of Texas A&M Research Annex, Bryan, Texas

showing the locations of the pavement test pads ... 3

Figure 2. Overall view of runway B showing the Jennite and

concrete test pads 4

Figure 3. Plan of test pads on runway B 5

Figure 4. Aggregate grading for TTI skid pads 9

Figure 5. Characteristic tread element patterns for the

16 sets of test tires 10

Figure 6. View of the 4x2 single- chassis flat-bed truck used

as the test vehicle 14

Figure 7. Data acquisition and recording instrumentation, plus

automatic tape recorder control and elapsed time

system 15

Figure 8. Overall view of the microphone location and test

vehicle 17

Figure 9. Data reduction and analysis system 18

Figure 10. Comparison of the maximum A-weighted sound levels

for tires with various types of construction 23

Figure 11. Comparison of the maximum A-weighted sound levels

for the 16 sets of test tires 24

Figure 12. Illustration of the effect of pavement surface and

tread wear for the 16 sets of test tires 26

Figure 13. Maximum A-weighted sound level versus pavement

surface for the 16 sets of test tires using the blank

tire as a pavement calibrator 28

Figure 14. Maximum A-weighted sound level versus pavement

surface for the seven sets of worn radial tires ... 29

ii
List of Tables

Page

Table 1. Summary description of Pad 1: Portland

cement concrete 6

Table 2. Summary description of Pad 2: asphaltic concrete

with Jennite flush seal 7

Table 3. Summary description of Pad 8: lightweight

aggregate hot-mix asphaltic concrete 8

Table 4. Average tread depth. Shore hardness and load rating

for the 16 sets of test tires 11

Table 5. Load and inflation pressure conditions for the

three tire load ratings 13

Table 6. Maximum A-weighted sound levels, as measured at

50 feet, for coastbys at a nominal speed of 50 mph

over the asphalt test surface 19

Table 7. Maximum A-weighted sound levels, as measured at

50 feet, for coastbys at a nominal speed of 50 mph

over the concrete test surface 20

Table 8. Maximum A-weighted sound levels, as measured at

50 feet, for coastbys at a nominal speed of 50 mph

over the Jennite test surface ' 21

Table 9. Increase of sound level with tread wear for the seven

sets of radial cross-bar tires on the three pavement

surfaces 31

iii
Conversion Table to SI Units

This publication uses customary English units for the convenience of

engineers and others who use them habitually. The table below is for

the reader interested in conversion to SI units. For additional

information see:

(1) NBS LC1056, November, 1977, "NBS Guidelines for Use of the

Metric System."

(2) NBS SP330, August, 1977 "The International System of Units (SI)."

Quantity To convert from To Multiply by

Length inch m (meter) 2.540 X 10-2 foot m 3.048 X 10-1 mile m 1.609 X 103 Area in2 m2 6.452 X 10-4

ft2 m2 9.290 X 10-2 Volume in 3 m3 1.639 X 10-5

ft3 m3 2.832 X 10-2 gallon m3 3.785 X 10-3 Temperature ° F

0 C t^ = (toP_32)/1.8

T. difference At°F K ATk = Atop/1.8

Mass pound kg 4.536 X 10-1 ounce kg 2.835 X 10-2 Pressure psi Pa 6.895 X 103

in H2 O Pa 2.488 X 102

in Hg Pa 3.386 X 103 mmHg Pa 1.333 X 102 Energy Btu J 1.055 X 103 MBtu J 1.055 X 109 kWh J 3.600 X 106

ft • Ibf J 1.356 X 10°

kilocalorie J 4.187 X 103 Power Btu/h W 2.931 X 10-1 hp W 7.457 X 102 Flow gal/min m3 /s 6.309 X 10-5

ft

3 /min m3 /s 4.719 X 10-4

Density lb/ft3 kg/m3 1.602 X 101 Ib/gal kg/m3 1.198 X 102 Heat Capacity Btu/(lb • 0 F) J/(kg • K) 4.187 X 103 Btu /(ft3 • 0 F) J/(m3 • K) 6.707 X 104

iv
Abstract

Recent advances in the development of heavy duty truck tires has lead to

the introduction of "quiet" design bias-ply cross-bar tires, as well as radial tires with cross-bar tread patterns. To adequately assess the

noise/safety/economic tradeoffs, acoustic data on a representative sample of

these newer tire designs are essential. This report presents acoustic data

measured at 50 feet for one type of new "quiet" design bias-ply and seven

types of radial cross-bar tires (both new and worn) for coastbys at 50 mph

on three pavement surfaces—asphalt, concrete and Jennite. In general, the

data show that these newer tire designs generate lower sound levels than

conventional bias-ply cross-bar truck tires. The differences in sound level

between these newer designs and conventional bias-ply cross-bars vary widely

and are a function of the individual tire and state of tread wear. These

data show that the sound level is dependent on pavement surface with a rank

ordering of asphalt (the lowest sound levels), concrete and Jennite. Also,

it is shown for the radial cross-bar tires that, depending upon the

particular tire, the sound level increases with tread wear from 0.8 to

9.0 dB on the asphalt and concrete pavements.

v

1. INTRODUCTION

Operational noise emission standards are presently in effect for

interstate motor carriers. Point-of-sale noise standards for medium and

heavy duty trucks have been promulgated and became effective January 1,

1978. Although noise control technology has been developed and demonstrated

to be feasible for most of the engine-related noise sources on trucks,

control of tire noise, which is predominant at highway speeds, remains an unsolved problem. If community noise levels are to be reduced near

highways, tire noise must also be reduced.

Although no more than a superficial understanding of the mechanisms of

tire noise generation exists, truck tire noise reductions can be

accomplished utilizing current tire technology. Existing data show that,

from both a cost and safety point of view, the use of quieter bias-ply or radial rib tires (rather than bias-ply cross-bar tires) provides at least

equal and, in general, more advantageous on-highway performance based on current tire use practices [ 1 ]

. — However, "quiet" design bias-ply

cross-bar tires, as well as radial tires with cross-bar tread patterns, are becoming commercially available. In order to develop the necessary

information base to adequately assess the noise/safety /economic tradeoffs,

there is a need to acquire acoustic data on a representative sample of these

newer tire designs.

The objective of this program is to determine the characteristic noise

levels generated by a sample of these newly designed bias-ply and radial

cross-bar truck tires. This report presents the results of coastby noise

measurements for one type of new "quiet" design bias-ply and seven types of

radial cross-bar tires (both new and worn). Section 2 contains a description of the field test site, test equipment and measurement

procedures. The results of these measurements are discussed in Section 3

and compared to data obtained previously for older design, conventional

bias-ply cross-bar truck tires.

2. FIELD TEST PROGRAM

The operational procedures and measurement /analysis instrumentation

utilized in this study were similar to that used in previous DOT/NBS truck

tire noise studies [2, 3], In the following sections detailed descriptions

are provided for the field test site utilized for data acquisition, the test

tires, vehicle configuration and the operational test procedures.

2.1 Field Test Site

The research runway of the Texas Transportation Institute (TTI) located

at the Texas A&M Research Annex, Bryan, Texas, was selected as the test site

1 / Numbers in brackets refer to literature references at the end of this

report.
for the data acquisition phase of the program. The layout of this test

site, located on property previously used as a jet-trainer airfield, is

shown in Figure 1. The tests were conducted on specially constructed pads.

These pads are located on runway B which is 150 feet wide and 7000 feet

long. An overall view of runway B showing two of the test pads can be seen

in Figure 2. The test pads consist of eight different pavements

representing a broad range of surface textures. These test pads, originally

designed for skid resistance research, are 24 feet wide and 600 feet long

with a cross slope of about 1/8 inch per foot. A detailed layout of the

eight test pads as constructed on runway B is shown in Figure 3.

Tests were conducted

2 ^n three of the eight pavement surfaces — Portland

cement concrete, Jennite- flush seal and the light-weight aggregate hot mix

(asphalt). These are test pads 1, 2 and 8, respectively. The

characteristics of each pad in terms of the materials used and the

techniques of surface finish or coating are discussed in detail in reference

[2] and summarized here in Tables 1, 2 and 3.

2.2 Test Tires

A total of 16 sets of tires were tested. These tires were loaned to the

government for this project by Garrett Freight Lines, Inc. and the

Kelly-Springfield Tire Company. These included one set of new "quiet"

design bias-ply cross-bar tires, 14 sets of radial cross-bar tires (new and

worn sets for seven different types) and one set of blank tires (full tread

depth but no tread pattern) . The characteristic tread patterns for these

tires are, shown in Figure 5 and the average tread depth — and Shore

hardness —' are given in Table 4.

2 / — Jennite is a commercially available clay-filled tar emulsion manufactured

by the Jennite Company, Houston, Texas. This material and all other

commercial products mentioned in this report are identified in order to

adequately describe the tests conducted in this program. In no case does such identification imply recommendation or endorsement by the

National Bureau of Standards, nor does it imply that these products

were necessarily the best available for the purpose.

3/ ~~ Tread depth measurements were taken at four equally spaced locations

around the tire circumference using a dial indicator. The operator

positioned the displacement rod on a major groove (not over sipes or other small grooves) , depressed the dial indicator until the base contacted

the tread surface, and noted the tread depth directly from the instrument.

4/ — The Shore hardness of the tread rubber was determined by ASTM test method

D2240-68 [5]. A type "A" durometer (for soft materials) was utilized in

the following manner: The durometer was held in a vertical position with

the point of the indentor at the center of the tread face. The presser

foot was applied to the specimen as rapidly as possible without shock,

keeping the foot parallel to the specimen surface. The scale was read

five seconds after the presser foot was in firm contact with the specimen.

The reported values represent the average for readings taken at approximately

the same four locations as the tread depth measurements.

2
Figure 1.

N

Plan of Texas A&M Research Annex, Bryan, Texas, showing the

locations of the pavement test pads.

3
4

Figure

2.

Overall

view

of

runway

B

showing

the

Jennite

and

concrete

test

pads
RUNWAY

CENTERLINE

24 FT. 24 FT. 24 FT. “ W ^ W W

PORTLAND JENNITE LIMESTONE

CEMENT FLUSH HOT MIX

CONCRETE SEAL TERRAZZO

FINISH

PAD PAD PAD

NO. 1 NO. 2 NO. 3

CRUSHED ROUNDED

GRAVEL GRAVEL

HOT MIX HOT MIX

PAD PAD

DIRECTION OF

NO. 4 NO. 5

VEHICLE TRAVEL

< LIGHT - ROUNDED

WEIGHT GRAVEL

AGGREGATE

CHIP SEAL

CHIP SEAL

PAD PAD

NO. 7 NO. 6

LIGHT - (WEIGHT

AGGREGATE

HOT MIX

PAD

NO. 8

Figure 3. Plan of test pads on runway B.

600

FT.

1

600

FT.

1

600

FT.

1

600

FT.
Table

1.

Summary

description

of

Pad

1:

Portland

cement

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ca o G

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c/o

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G rH 4J 03 G c G > G G G a O Ci G G oo o m • 0 i—i

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42

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Table

2.

Summary

description

of

Pad

2:

asphaltic

concrete

with

Jennite

flush

seal.

CD CD *

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X •>

m

(0 3 £ C o u o u h o

<d

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•H 3 3

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CJ

X

m > 3 cn 33 3 a • <£ x 3 CO

CO

X •fc <3 3 < * +-7
Table

3.

Summary

description

of

Pad

8:

lightweight

aggregate

hot-mix

asphaltic

concrete. * 3 ai *

00

n CN

(0 3 -3 3 CM

(-4 4-4 4-1 *H

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0)

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•H 00 44 •H rH •H •H

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4-J 4H 3

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ONISSVd lN30U3d

9

Figure

4.

Aggregate

grading

for

TTI

skid

pads.
Blanks Kelly-Springfield

Registered

“Whisper” Drive

New Worn

Bridgestone V-Steel Mix

New

Goodyear Radial D-605

New Worn

Yokohama Super Steel 745B

Figure 5. Characteristic tread element patterns for the 16 sets of test tires

10
Table 4. Average tread depth, Shore hardness and load rating for the

16 sets of test tires.

TEST CARCASS LOAD STATE AVERAGE AVERAGE

TIRE CONSTRUCTION RATING OF WEAR TREAD SHORE

DEPTH, in HARDNESS

3r idgestone radial G new 0.642 66

/-Steel Mix worn 0.294 65

Dunlop radial H new 0.628 65

Steel Radial

3P777 All Season

worn 0.365 66

r irestone radial G new 0.685 62

Power Drive

[ransteel Radial

worn 0.256 65

3. F. Goodrich radial G new 0.526 66

Bilvertown Milesaver

Radial HDB worn 0.328 61

Goodyear radial G new 0.676 69

Radial 410 worn 0.251 63

Goodyear radial G new 0.675 65

Radial D-605 worn 0.339 65

Yokohama radial H new 0.614 64

Super Steel 745B worn 0.256 63

Kelly-Springf ield

Registered "Whisper"

Drive

bias-ply F new 0.779 65

Blanks bias-ply F new — 67

11
The test tires were all size 11.00-24.5. The load ratings were "F" for

the blanks and bias-ply tires and either "G" or "H" for the radial tires

(see Table 4) . All tests were conducted using the maximum inflation

pressure and 75 percent of the maximum tire load recommended by the Tire and

Rim Association for each load rating [6]. These inflation pressures and

loads are listed in Table 5.

The test tires were always mounted on the drive axle of the test

vehicle. Blank tires, which had a characteristic tire noise level that was

as low as or lower than that of the test tires, were mounted on the steering

axle. For each set of tires, the vehicle was run for a minimum of five

miles to allow the tires to warm up. Immediately following this, the

acoustic measurement test runs were made.

2.3 Test Vehicle

The test vehicle utilized in this study was a General Motors Corporation

Model 6500 4x2— single-chassis flat-bed truck with a conventional cab.

This vehicle was equipped with 10-hole Budd wheels, 366 CID gasoline engine,

5-speed transmission and 2-speed axle. All tests were run in a coastby mode

(with the engine shut-off) at a nominal speed of 50 mph. The vehicle was loaded according to the particular tire being tested (see Table 5). An

overall view of the vehicle is shown in Figure 6.

2.4 Test Procedures

The test procedures utilized were essentially identical to those

specified in SAE J57a — Sound Level of Highway Truck Tires [7] — . The two

exceptions were that the distance between the point of entrance and point of

exit of the test section was 600 feet and that "fast" response was utilized

for data analysis.

The components of the data acquisition and recording instrumentation,

plus the automatic tape recorder control and elapsed time system utilized,

are shown in Figure 7.

Three tape switches — one immediately before the test section and one each at the beginning and end of the test section — were used to start and

stop the recorder and to mark the data tapes to designate the start and end

of data. The tape switches at the beginning and end of the test section

were also used to control an elapsed time system which provided a direct

readout of average vehicle speed in miles per hour.

— The nomenclature 4x2 relates to the number of wheel positions — 4, and

the number of driven positions — 2, but has no relationship to the number

of tires — 6.

fS / — The complete text of SAE J57a is reproduced in Appendix A.

12
Table

5.

Load

and

inflation

pressure

conditions

for

the

three

tire

load

ratings.

W

Pd

P=> CO

CO rH w CO Pd •H 1 m o

Ah -d 1 CO rH

co 1 rH s Pd o •H H CO H a, 5 >s 2 rH M Ah1 <n i i a CO i i co o -H o PQCo

•H <d 4-1 <u P2 cO 3 rO co o 00

•H

H

a o CO CsJ

H a) 00 CM X)

<4-1

B *

4-1 1 3 B CO <r

CO o

0) S'? o H m 0)

pci

M

a) AhT3

CO rH O cO o uo U0

XI 3 X> Mf rH

4J 00 CM X) O * A *

<d CO <r o o O

<D vj- 00 x>

XI > a) rH •H rH #» * ! -t * m X5 00 Q O <i rH rH rH 1

XI 60 5 o o o

*4 *•3- CM X>

<u cu CT\

0) rH «s * 4J * n- r^. CO

4-» x:

60

CO •H

CO CL) o o o 0 13 00 o CM u tH cn Ol O <u A #* iH CO <n

rH o 04 CM CM

CO •H

-1 X! 0 a) H >oz w C3 M

PdH IH

O S3

M

C

-> <H

Hhj p2

13
14

Figure

6.

View

of

the

4x2

single-chassis

flat-bed

truck

used

as

the

test

vehicle.
cc O — < X

CJ

LU

UO

O

<

z

<

Q- oo < >-

I— t/>

15

Figure

7.

Data

acquisition

and

recording

instrumentation,

plus

automatic

tape

recorder

control

and

elapsed

time

system.
The acoustic measurement system consisted of a 1/2-inch condenser

microphone, a battery-operated microphone power supply (to supply the

polarization voltage to the microphone), a step attenuator which provided

the capability for selection of gain over a range of 60 dB in 10 dB steps,

and a tape recorder with two direct record analog data channels and one

m FMm timing channel. The system included both a flat frequency response hold

capability — which provided an indication as to whether or not a tape

recorder channel had saturated (saturated runs were repeated) — and an A-weighting hold capability — which provided a direct reading, in the

field, of the maximum A-weighted sound level observed during a passby

without having to return to the laboratory for analysis of the tapes. The

measurements were performed out-of-doors; therefore, a windscreen was placed

over the microphone to reduce the noise produced by wind passing over the

microphone grid. A hand-held rotating vane anemometer was used to measure

wind speed. No measurements were made for wind speeds greater than 12 mph.

A single point calibration utilizing a pistonphone which produces a 124 dB

sound pressure level (re 20 yPa) at a frequency of 250 Hz was used for

system calibration in the field. Figure 8 shows the microphone location and

associated instrumentation in the field at the TTI test site.

Once the data had been recorded, the analog tapes were returned to the

National Bureau of Standards for reduction and analysis. Figure 9

identifies the equipment which was utilized for analysis purposes. Each

tape was played back through the real-time analyzer. An interface-coupler

was necessary to make the real-time analyzer compatible with a minicomputer.

When a timing signal appeared on the analog tape, the computer was instructed to start sampling the digital data from the real-time analyzer at

a rate of 20 times per second. A time constant of 120 msec, which

corresponds to "fast" response [8], was used to obtain the A-weighted sound

levels. Once all data had been analyzed, the computer stored the data and

dumped it onto digital magnetic tape. This tape was formated to be

acceptable to the large NBS computer which was utilized for further

analysis. The results of these tests are discussed in the next section.

3. TEST RESULTS

For this study a minimum of two passbys were made for each test condition.

Passbys were repeated until two test runs were obtained with the maximum

A-weighted sound levels within 2 dB and the vehicle speeds within 2 mph.

The results reported in this section consist of the maximum A-weighted sound

levels for each of these coastbys and the arithmetic average of these

values. These data, given in Tables 6, 7 and 8, are compared with existing

data in Section 3.1. The effects of pavement surface and tread wear on the

resultant sound levels are examined in Sections 3.2 and 3.3.

16
17

Figure

8.

Overall

view

of

the

microphone

location

and

test

vehicle.

The

tripod-mounted

microphone

was

located

50

feet

(15.2

m)

from

the

centerline

of

vehicle

travel

along

a

line

perpendicular

to

the

vehicle

path.
18

Figure

9.

Data

reduction

and

analysis

system.
Table 6. Maximum A-weighted sound levels, as measured at 50 feet, for

coastbys at a nominal speed of 50 mph over the asphalt test

surface. "Fast" meter response was utilized.

TEST TIRE TREAD

DESIGN

STATE

OF

TREAD

WEAR

SPEED,

mph

A-WEIGHTED SOUND

LEVEL, dB re 20 yPa

Maximum

Average of the

Two Maximum

Values

Blanks bias-ply new 50.3

50.4

72.6

72.0

72.3

Kelly-Springf ield

Registered "Whisper"

Drive

bias-ply new 50.0

50.1

74.6

74.6

74.6

Bridgestone

V-Steel Mix

radial new 49.7

49.3

71.6

72.2 71.9

worn 49.7

49.9

74.0

74.0

74.0

Dunlop Steel Radial

SP777 All Season

radial new 49.7

50.0

72.4

71.4 71.9

worn 49.6

49.6

76.8

76.0

76.4

Firestone Power

Drive Transteel

Radial

radial new 50.6

50.7

74.2

74.4

74.3

worn 50.1

50.1

77.2

77.8 77.5

B. F. Goodrich

Silvertown

Milesaver Radial HDB

radial new 50.4

50.5

72.4

72.2

72.3

worn 50.5

50.5

80.2

80.0 80.1

Goodyear Radial 410 radial new 50.5

50.3

74.0

73.0 73.5

worn 50.1

50.5

76.6

76.4 76.5

Goodyear Radial D-605 radial new 49.7

49.6

73.0

74.0 73.5

worn 50.6

50.6

82.6

82.2 82.4

Yokahama Super

Steel 745B

radial new 50.3

50.6

72.0

72.8

72.4

worn 50.0

50.1

72.8

73.6

73.2

19
Table 7. Maximum A-weighted sound levels, as measured at 50 feet, for

coastbys at a nominal speed of 50 mph over the concrete test

surface. "Fast" meter response was utilized.

TEST TIRE TREAD

DESIGN

STATE

OF

TREAD

WEAR

SPEED,

mph

A-WEIGHTED SOUND

LEVEL, dB re 20 yPa

Maximum

Average of the

Two Maximum

Values

Blanks bias-ply new 50.8

50.4

74.4

74.8 74.6

Kelly-Springf ield

Registered "Whisper"

Drive

bias-ply new 50.2

50.4

76.4

76.8 76.6

Bridgestone

V-Steel Mix

radial new 50.3

50.2

74.0

74.8

74.4

worn 50.0

50.1

76.8

76.2

76.5

Dunlop Steel Radial

SP777 All Season

radial new 50.3

50.5

74.0

73.8

73.9

worn 49.7

50.6

78.8

78.6

78.7

Firestone Power

Drive Transteel

Radial

radial new 51.2

50.1

76.2

76.6

76.4

worn 50.4

50.4

79.0

78.8

78.9

B. F. Goodrich

Silvertown Milesaver

Radial HDB

radial new 50.2

50.8

74.2

74.2

74.2

worn 50.9

50.3

82.0

81.2

81.6

Goodyear Radial 410 radial new 50.8

50.3

76.2

76.0 76.1

worn 50.0

50.8

79.6

79.2

79.4

Goodyear Radial D-605 radial new 50.0

50.5

74.6

74.6

74.6

worn 50.6

50.3

83.6

83.6

83.6

Yokohama Super

Steel 745B

radial new 50.9

50.8

74.6

75.2

74.9

worn 50.3

50.2

76.4

76.6

76.5

20
Table 8. Maximum A-weighted sound levels, as measured at 50 feet, for

coastbys at a nominal speed of 50 mph over the Jennite test

surface. "Fast" meter response was utilized.

TEST TIRE TREAD

DESIGN

STATE

OF

TREAD

WEAR

SPEED,

mph

A-WEIGHTED SOUND

LEVEL, dB re 20 yPa

Maximum

Average of the

Two Maximum

Values

Blanks bias-ply new 50.4

50.7

75.6

74.8

75.2

Kelly- Springfield

Registered "Whisper"

Drive

bias-ply new 51.5

50.6

77.8

77.8 77.8

Bridgestone

V-Steel Mix

radial new 50.6

50.5

75.6

74.8 75.2

worn 49.8

49.6

80.6

80.2

80.4

Dunlop Steel Radial

SP777 All Season

radial new 50.0

50.6

75.0

75.0

75.0

worn 49.9

50.1

81.0

80.8

80.9

Firestone Power

Drive Transteel

Radial

radial new 49.5

50.3

76.8

77.0 76.9

worn 49.6

50.5

80.8

80.8 80.8

B. F. Goodrich

Silvertown Milesaver

Radial HDB

radial new 50.7

50.6

75.6

75.6 75.6

worn 50.3

50.6

82.4

82.4 82.4

Goodyear Radial 410 radial new 50.5

50.5

76.4

76.6

76.5

worn 50.6

50.5

83.0

81.2

82.1

Goodyear Radial D-605 radial new 50.7

50.4

75.8

74.8 75.3

worn 49.9

50.8

86.4

86.4 86.4

Yokohama Super

Steel 745B

radial new 51.3

51.6

75.6

75.8 75.7

worn 50.6

50.4

78.4

80.0 79.2

21
3.1 Comparison of Results with Existing Data

for Bias-Ply Cross-Bar Tires

Because radial truck tires are relatively new on the U.S. commercial

market, the majority of existing data is for bias-ply tires. A summary of

the range of maximum A-weighted sound levels for various types of tire

construction, taken from references [2, 3, 9-14], is shown in Figure 10.

Also shown in Figure 10 are the results from the current study. In this

figure, the unshaded portion of each bar represents the range between the

upper and lower values of the maximum A-weighted sound level for that type

of tire.

For the existing data shown in Figure 10, bias-ply cross-bar tires

generate the highest sound levels of the four general types of tires grouped

according to carcass construction and tread pattern. Radial ribs, on the

other hand, generate the lowest sound levels, with bias-ply ribs and radial

cross-bars being about equal and in-between these upper and lower values.

The data from the current study show a marked reduction of sound level

(approximately 2-5 dB) for the "quiet” design bias-ply cross-bar when new. Unfortunately, worn tires of the same type were not available for testing.

The data for the new radial cross-bars agrees with the existing data, but

the interesting aspect is the effect of tread wear. Although the upper

limit of the maximum A-weighted sound level is comparable to that for

bias-ply cross-bars, the lower limit is substantially less. The bars in

Figure 10 for the tires in the current study include data for all three

types of navement surface. If the data for the Jennite surface are excluded — t the upper limits drop to the dashed lines shown in each bar.

This reduces the upper limit by approximately 3 dB for the worn radial

cross-bars, which indicates that as a group they generate lower sound levels

than bias-ply cross-bar tires.

As indicated by the large range between the upper and lower values of

the maximum A-weighted sound levels, there are differences between the

individual types of tires tested in this current study. These differences

are shown in Figure 11. As in Figure 10, the unshaded portion of each bar

represents the range between the upper and lower limits measured for that

tire on the three pavement surfaces. The existing data for bias-ply

cross-bars are shown for reference purposes on the extreme right of this

figure

.

When new, the seven types of radial cross-bar tires generate

approximately the same range of sound levels on the three pavement surfaces

— The Jennite test surface was chosen for testing because it is similar to an asphalt surface which has an excessive amount of sealer on it. As will

be shown in Section 3.2, the sound levels were the highest on the Jennite

surface for all tires tested. Since the existing data shown in Figures 10

and 11 are for coastbys on concrete and asphalt pavements, a more accurate

comparison can be made if the data for the Jennite surface are excluded.

22
Rib Cross-Bar Rib Cross-Bar Cross-Bar Cross-Bar

Figure 10. Comparison of the maximum A—weighted sound levels for tires with

various types of construction. The unshaded portion of each bar

represents the range between the upper and lower values for that

type of tire. The dashed line represents the upper limit excluding

the data for the Jennite surface.

23
03

CO 11 co 1 . 5 m

=3 CO oo in _ *3- E _ c 5 a> 5 0 « QJ ^

LL. CO

00

—i

Worn

New :

Worn:

OJ OJ 5 52 o c/>

.e

LL.

g = ra

C 1| C© 1 : 3: s

a> =? '

03

O

03 .

a>

moo coir>

i"- ioCO CO

edH OZ 3J 8P ‘|3Aa~| punos pam6;3M-V tunuijxeiAl

<u 3

(0

X 3

.3 CO 4-1O

Eh CU •H 3 CO 4-1

4-1 3 • cd 3 3

CO > <U >

a) CO 3 u Pi CU O

•H CU Pi

u

4-1 5 a, o CU Pi

4-1 1—t

Pi

O

CD 4-4 0) T) (U

4-1 3 3 3

cd •H 4-1 4-4 i—1 3 o Pi X)

CU

T3 CO a. <U OO

•U Cu

X 3 3 3 CO •H

CO cd 4-1 CU T3 Cfl vO X -H i—1

4-1 CU

X

-3

w

a) c H X CU 4J <U& • 3

i-i 4-1 CO CJ o CU CU 3 m X a 4-1 3 Pi

CO CU 4-1 3 1—1

00 Pi 3

(0 c 3 > cd CO 3

Cl) 4-1 1—I

4-1 •H

CU 3 3

TJ

X cu 3 3 4-1 e 3 3 0) >-3 O CO >

CO 4-1 3 3 3 a X T3 CU 4-1 a) CO 3

4-1 (U 3 Pi X Pi Pi O

00

ax 4-4 •H <u 4~> 35I < 3x 3 x 5 ° oX 3 3 u x4-1 oj a) T3 Pi

cd 3X 3

cd

a) X 3 Pi oo •rl 3 •r) 3 4-1 e 4H 4-1 •H o 3) Pi 3 4-1 3 3 X 3 3 i—1 4-1 o X 3 1 •H 4-1 X 3 4h 4-1 3 3 o Pi Pi O o o 4-1 Pi 3 a- 4-4 •H CJ o 6 3 TJ TJ •H -H 3 3 r—1

r-H Pi 33 Pi a- 3 3 3 M i CL, ,3 3 3 3 s 3 3 a. 3 o 3 3 a H o 3 e 3 X

ai

)-i P

oo

•Hp4

24
(71.4 to 74.2 dB for the lower values and 75.0 to 77.0 dB for the upper

values) . The variation is more apparent for these tires when they are worn

(the lower values vary from 74.0 to 82.2 dB and the upper values 80.0 to

86.4 dB). If the data for the Jennite surface are again excluded (shown by

the dashed line in each bar), the upper values are reduced, but the range

between these values remains about the same. Although the upper limit for

the Goodyear Radial D-605 is reduced by excluding the data for the Jennite

surface, the upper limits for the Bridgestone V-Steel Mix and Yokohama Super

Steel 745B are also reduced. In this case, the upper limits for these latter

two types of tires are below the lower limits for the existing data on conventional bias-ply cross-bars, even when new. Thus, based solely on noise considerations, radial cross-bar tires would be preferable to bias-ply

cross-bar tires. Realistically though, noise considerations play only a small role in the overall evaluation of a tire. Other factors such as traction and handling, tread wear, fuel economy and costs must also be

considered.

3.2 Effect of Pavement Surface

As shown in the previous section in Figures 10 and 11, pavement surface

can have a significant effect on tire noise. This effect is dependent upon

a complex interrelationship between tire construction, tread design and

state of wear, and pavement surface characteristics. The exact nature of

this relationship is not known and previous attempts to relate tire noise

with any type of quantitative measure of the pavement surface

characteristics have had limited success [2],

The effect of pavement surface is shown for the three pavements tested

in this study in Figure 12. In this figure each bar represents one of the

three pavements. The upper limit of the shaded portion of each bar

corresponds to the maximum A-weighted sound level (average of the two test

runs) for the new tire and the unshaded portion for the worn tire. As seen

in Figure 12, the rank ordering of the pavements based on sound level is the same for all 16 sets of test tires—asphalt (the lowest), concrete and

Jennite. The increase of maximum A-weighted sound level for the concrete

surface relative to the asphalt surface is relatively consistent for all

test tires and averages 2.1 dB (standard deviation of 0.6 dB) . The increase

in going from the concrete surface to the Jennite is dependent upon tire

tread wear. For the new radial tires the average increase is 0.8 dB

(standard deviation of 0.3 dB) and for the worn radial tires 2.4 dB

(standard deviation of 0.9 dB)

.

One of the empirical techniques that has been applied as a means for

characterizing pavement surface involves using a particular tire to rank

order or "calibrate" the surfaces. In reference [2], a pocket tread tire

(tread design consists of pockets that are not vented to the outside

shoulder of the tire) was used as a pavement calibrator, but the results

were inconclusive. However, data from a study of passenger car tire noise

25
=3 CD co m

01 TJ- >•O gCQ C9

u e >-

(S 9) oi .S

Q1 Qj s S

=> t; _ “-cm

oi 2 ^ g'-s

ts §

S c

iZ ca

oi <= S r» g W g; co CO 03 J- — co

.2 <u _ es ^ —

03 __

1C ^

o» 2?

gj £2 CC 1c3

edrl OZ 3J 8P ‘I3A31 punos pam&aM-V uinuijxen

26

Figure

12.

Illustration

of

the

effect

of

pavement

surface

and

tread

wear

for

the

16

sets

of

test

tires.

The

upper

limit

of

the

shaded

portion

of

each

bar

corresponds

to

the

average

maximum

A-weighted

sound

level

when

the

tire

is

new

and

the

unshaded

portion

for

the

tire

when

worn.
[15], also examined in reference [2], showed that blank tires might be

useful as a pavement calibrator. Data for the 16 sets of tires are plotted

in Figure 13 using the blank tire as a calibrator. This is done by

arbitrarily chosing the end points for the asphalt and Jennite surfaces and

adjusting the location of the concrete surface along the horizontal axis to

get the best fit to a straight line. If the surfaces are assigned the

numbers 1 for asphalt and 9 for Jennite, the value giving the best fit for

concrete is 7.35. As seen in Figure 13, the fit with the linear regression

line is quite good for all of the new tires. However, the fit is not as good

for the worn radial tires. Averaging the values for the seven sets of worn

radial tires, the optimum surface number for concrete is 4.82. The data for

the worn radial tires are replotted in Figure 14 using this average value

for concrete. As expected, the fit to the linear regression line is much

improved.

Although the data fit for the worn tires was not as good as desired, it

does appear that blank tires could be used as a pavement calibrator for the

new tires. This conclusion is somewhat tentative because tests were

conducted on only three pavement surfaces. Data obtained at the same test

site show that these three pavements do not encompass the total range of

pavement surface characteristics that exist [2] (although they do encompass

the vast majority found on today's roads). Thus, before any final

conclusions can be made, data for other types of surfaces are required.

3.3 Effect of Tread Wear

In the two previous sections, a distinction was made between new and

worn tires when comparing the results of this study with existing data and

when examining the effects of pavement surface. In both cases tread wear

was shown to have an effect on the resultant sound level.

As seen in Figure 10, existing data on tread wear are limited to

bias-ply rib and cross-bar tires. Because very little information is

available, no data are presented on the effect of tread wear for radial

truck tires. The data for bias-ply tires are limited to two or three

different states of wear between new and fully worn [10]. These data show

that in general the sound level increases with tread wear. In some cases

the sound level increases uniformly with tread wear, while in others it

reaches a maximum then decreases slightly when fully worn. The magnitude of

the increase in sound level with tread wear is dependent upon the particular

tire and pavement surface. Based on existing data the maximum increase is on the order of 2-3 dB for bias-ply rib tires and 4-6 dB for bias-ply

cross-bar tires.

The effect of tread wear for the seven sets of radial cross-bar tires

(these tires were worn in fleet service) examined in this study is also

illustrated in Figure 12. As seen in this figure, the sound level increases

27
Maximum

A-Weighted

Sound

Level,

dB

re

20

(iPa

80

75

70

85

80

75

70

85

80

75

70

90

85

80

75

70

01 23456789 10

—i—i—i—

r

1 1 1

1 1 Goodyear Radial D-605

Worn

New a —~——-—nr

1 r* ~

ffl ——

-

Asphalt

1 1 1 i

Concrete Jennite

1 i it 1 4

i—i—s—i—i—s—i—i—

r

Dunlop Steel Radial SP777 All Season

1 I I I I I I I L

Pavement Surface

Figure 13. Maximum A-weighted sound level versus pavement surface for the 16 sets of

test tires using the blank tire as a pavement calibrator. The solid line

corresponds to the linear regression line using a value of 7.35 for the

concrete surface.

28
O)

'gj

Pavement Surface

Figure 14. Maximum A-weighted sound level versus pavement surface for the seven

sets of worn radial tires. The solid line corresponds to the linear

regression line using the average value of 4.82 for the concrete surface.

29
with tread wear as it did for the bias-ply tires. The magnitude of the

increase, represented by the length of the unshaded portion of each bar,

varies widely and is dependent upon the particular tire and pavement

surface. These increases of A-weighted sound level are listed in Table 9.

As shown in this table the range of increases is about the same for the

asphalt and concrete pavements (0.8 to 9.0 dB) and slightly higher (3.5 to

11.1 dB) for the Jennite surface. Because of the high degree of variability

of the magnitude of this increase for the seven sets of tires, no general

conclusions can be made except that sound level increases with tread wear.

It should be noted that although the increases of sound level with tread

wear are greater than for conventional bias-ply cross-bar tires, the sound

levels for the worn radial cross-bar tires are still comparable to, and in

most cases less than, that for worn bias-ply cross-bars.

3.4 Conclusions

Based upon the data presented in this report, the following conclusions can be made:

The sound level for the new "quiet" design bias-ply cross-bar tires is

approximately 2-5 dB lower than existing data for conventional bias-ply

cross-bar tires when new. Data for this tire when worn are needed to

determine the effect of tread wear.

Considering only the data for the asphalt and concrete pavements, the

radial cross-bar tires tested in this study generate lower sound levels

than conventional bias-ply cross-bar tires, especially when worn.

The sound level increases with tread wear for the radial cross-bar

tires. The magnitude of this increase is strongly dependent on the

individual tire and varies from 0.8 to 9.0 dB on the asphalt and

concrete pavements.

Pavement surface has a significant effect on the sound generated by

"quiet" design bias-ply and radial cross-bar tires. The rank ordering

of the pavements based on sound level is the same for all 16 sets of

test tires — asphalt (the lowest), concrete (2.1 dB higher than

asphalt), and Jennite (new - 0.8 dB, and worn - 2.4 dB, higher than

concrete)

.

It appears that for the three pavements tested, blank tires might be a reasonable pavement calibrator for new cross-bar tires. Data for other

types of pavements are required to fully validate this hypothesis.

30
Table 9. Increase of sound level with tread wear for the seven sets of

radial cross-bar tires on the three pavement surfaces.

TEST TIRE

INCREASE OF SOUND LEVEL WITH TREAD WEAR, dB

Asphalt Concrete Jennite

Bridgestone

V-Steel Mix

2.1 2.1 5.2

Dunlop Steel Radial

SP777 All Season

4.5 4.8 5.9

Firestone Power

Drive Transteel Radial

3.2 2.5 3.9

B.F. Goodrich Silvertown

Milesaver Radial HDB

7.8 7.4 00

Goodyear Radial 410 3.0 3.3 5.1

Goodyear Radial D-605 8.9 9.0 11.1

Yokohama Super

Steel 745B

o 00 1.6 3.5

31
4. APPENDIX A SAE RECOMMENDED PRACTICE FOR MEASUREMENT OF TRUCK TIRE NOISESOUND LEVEL OF HIGHWAY

TRUCK TIRES— SAE J57a SAE Recommended Practice

Report of V ehicle Sound Level Committee approved July 1973 and last revised June 1976 Approved by American National Standards Institute November 1976 Rationale Statement available.

/. Introduction—This SAE Recommended Practice establishes a test pro- cedure for measuring the sound level produced by tires intended primarily for- highway' use on motor trucks, truck tractors, trailers and semitrailers, and

buses. The procedure provides for the measurement of the sound generated by

a set of test tires, mounted on the rear axle operated at 80 km/h (50 mph) and

at maximum rated tire load

Specifications for the instrumentation, the test site, and the operation of the

test vehicle are set forth to minimize the effects of extraneous sound sources and to define the basis of reported sound levels. Factors influencing sound level measurement and reference to sound levels are given in the Appendix.

2. Instrumentation—The following instrumentation shall be used for the measurements as required:

2.1

A sound level meter which satisfies the Type 1 requirements of American National Standard Specification for Sound Level Meters, SI. 4-1971.

2.1.1

As an alternative to making direct measurements using a sound level meter, a microphone or sound level meter may be used with a magnetic tape

recorder and/or a graphic level recorder or other indicating instrument, providing the system meets the requirements of SAE J184, Qualifying a Sound Data Acquisition System, with slow response specified in place of fast response as applicable to paragraph 3.6 therein.

<> 2.2 An acoustical calibrator, having an accuracy of ±0.5 dB, for establishing the calibration of the sound level meter and associated instrumentation.

<f> 2.3 An anemometer having an accuracy of ± 10% at 19 km/h ( 12 mph)

3. Test Site

3.1 The test site shall be located on a flat area which is free of reflecting surfaces (other than the ground), such as parked vehicles, trees, or buildings within 30 m (100 ft) of the measurement area. 3.2 The vehicle path shall be relatively smooth, semipolished, drv, Port- land cement concrete which is free of extraneous surface material.

3.3 The microphone shall be located 15 m (50 ft) from the centerline of the vehicle path at a height of 1.2 m (4 ft) above the ground plane The

normal to the vehicle path from the microphone shall establish the micro- phone point on the vehicle path. See Fig. 1. 3.4 The test zone extends 15 m (50 ft) on either side of the microphone

point along the vehicle path. The measurement area is the triangular area formed by the point of entrance into the test zone, point of exit from the test zone, and the microphone.

3.5 The measurement area should be surfaced with concrete, asphalt, or

similar hard material and, in any event, shall be free of snow, grass, soil, ashes, or other sound-absorbing materials. 3.6 The ambient sound level (including wind effects) at the test site shall be at least 10 dB below the level of the test vehicle operated in accordance

with the test procedure.

3.7 The wind speed in the measurement area shall be less than 19 km/h

(12 mph).

FIG. 1—TEST SITE (SEE PARAGRAPH 3). (VEHICLE MAY BE RUN IN EITHER DIRECTION)

8 / Reprinted with permission from 1978 SAE Handbook © 1978 Society of Automotive

Engineers, Inc.

32
4. Test \ tkicle

4.1 The vehicle shall be a motor truck equipped with two axles (a nonpowered steering axle and a powered axle). 4.2 The vehicle shall have a platform, rack, or van body capable of retaining the loading or ballast. This body shall have an essentially flat and

horizontal undersurface, and be mounted such that this surface has a 230 100 mm ( 9 — 4 in) clearance with the tire fully loaded. This body shall be nominallv 2440 mm (96 in > in width and extend a minimum of 910 mm

36 in) rearward of the rear (powered) axle centerline.

4.3 Mud flaps should be removed at the test site, if permissible.

5. Tires

5.1 Tires used for dual installations shall be dual mounted (four tires) on

the rear axle for testing. Tires used in single installations (wide base) shall be mounted singly. A tire used as both duals and singles may require test at both

dual and single mounting. The sound level reported must be identified as to type of mounting.

5.2 The tires shall be inflated to the maximum pressure and loaded to the maximum load specified by the Tire and Rim Association for continuous

operation at highway speeds exceeding 80 km ' h (50 mph).

5.2.1 If local load limits will not permit full rated load, the test may be conducted ?.* the local load limit with inflation pressure reduced to provide a

•v. jm load and inflation pressure, provided the

l.iJ s Ov. Kss than 75 c of the maximum rated load. As an alternative, the pressure in the tires can be adjusted to correspond to the actual load following the appropriate load/pressure tables in the Tire and Rim .Association Yearbook. Because the choice of procedure may cause small

differences in level, such levels shall not be reported unless they are identified with the percent load used. 53 Quiet tires are recommended for use on the front axle.

6. Rrocethtre

6.1 The test vehicle shall be operated in such a manner (such as coasting)

that the sound level due to the engine and other mechanical sources is minimized throughout the test zone. The vehicle speed at the microphone

point shall be 80 km/h (50 mph). 63 The sound level meter shall be set for slow dynamic response and the A-weighting network. The observer shall record the highest level attained during each pass of the test vehicle, excluding readings where known acoustical interferences have occurred.

6.2.1 .Alternatively, each pass of the test vehicle may be recorded on magnetic tape and subsequently analyzed with a sound level meter and/or graphic

level recorder. 63 There shall be at least three measurements. The number of measure- ments shall equal or exceed the range in decibels of the levels obtained.

6.4 The sound level reported shall be the average of the two highest readings which are within 2 dB of each other.

7. General Comments

7.1 It is recommended that technically competent personnel select the equipment to be used for the test measurements and that these tests be conducted only by persons familiar with the current techniques of sound

measurement.

7.2 All instrumentation should be operated according to the practices recommended in the operating manuals or other literature provided by the manufacturer All stated precautions should be observed. Some specific items

for consideration are:

7.2.1 Specifications for orientation of the microphone relative to the ground

plane and the source of sound should be adhered to. (Assume that the sound

source is located at the microphone point.)

7.2.2 Proper signal levels, terminating impedances, and cable lengths should be maintained on all multi-instrument measurement systems.

7.2.3 The effect of extension cables and other components should be taken

into account in the calibration procedure.

7.2.4 The position of the observer relative to the microphone should be as recommended.

7.3 Instrument manufacturer’s recommended calibration procedure and

schedule for individual instruments should be employed. Field calibrations should be made immediately before and after testing each set of tires. 7.4 Not more than one person, other than the observer reading the meter, shall be within 15 m (50 ft) of the vehicle path or the microphone, and

that person shall be directly behind the observer reading the meter, on a line through the microphone and the observer.

7.5 The sound level of the tires being tested is valid only when the sound

level of the vehicle equipped with quiet tires is at least 10 dB below that of the vehicle equipped with test tires. The sound levels obtained with this proce- dure may be used for a relative ranking of the test tires, if the sound level of the vehicle equipped with the quietest tires available is 3-10 dB lower than when equipped with the tires being tested.

8. Reference Material—Suggested reference material is as follows:

8.1 ANSI SI. 1-1960 (R1971), Acoustical Terminology

8.2 ANSI Si. 2-1962 ( R 1 97 1 ), Physical Measurement of Sound

8.3 ANSI Si.4- 197 1, Specification for Sound Level Meters

<> 8.4 SAE Recommended Practice J 184, Qualifying a Sound Data Acquisition System 83 Tire and Rim Association Yearbook

8.6 SAE Publication SP-373, Truck Tire Noise

8.7 G. R. Thurman, “Effect of Road Surface and Bed Clearance on Truck Tire Noise.” Paper 740607 presented at SAE West Coast Meeting, Anaheim, California, August 1974. The ANSI documents are available from the American National Standards

Institute, Inc., 1430 Broadway, New York, New York 10018.

APPENDIX

Al. An A-weighted sound level not exceeding 85 dB, determined in ac- cordance with this recommended practice, is consistent with present best current practice for cross ribbed tires in normal states of wear. It is general experience that the sound level of unworn tires is significantly less than that of worn tires.

<> A2. Road surfaces are known to significantly affect the sound levels gener- ated by highway truck tires. Rib type tires generally produce lower sound

levels on smooth surfaces than on surfaces having a textured finish such as that brushed in during construction. Differences as great as 5 dB have been

observed between sound levels obtained on very smooth and coarse concrete

surfaces for tires producing relatively low levels of sound. For cross-ribbed

tires, however, generated sound levels have been found to not differ by more

than approximately 1 dB for given tire types on a variety of Portland cement

concrete surfaces judged to be relatively smooth. For these reasons, the vehicle path description in paragraph 3.2 is sufficient to provide for reproducible sound levels for cross-ribbed tires, within the expected accuracy of such measurements (ztl dB), and to provide surface-dependent relative sound

levels for rib type tires. A3. Persistence of tire sounds after the passage of the vehicle and the tonal components of these sounds are properties of certain types of tires which tend

to occur concurrently. Both are factors that direct attention to the sound, and

are important determinants of the acceptability of the sound

33
5. REFERENCES

[1] Leasure, Jr., W. A., Tire Noise Regulations - Technical and Economic

Implications, SAE Paper 762033, published in SAE Publication P-70: SAE

Highway Tire Noise Symposium Proceedings, San Francisco, California,

November 10-12, 1976.

[2] Kilmer, R. D. , Leasure, Jr., W. A., and Mathews, D. E. , Truck Noise 1-C

Pavement Surface Effects on the Generation of Truck Tire Noise, U. S. Department of Transportation Report No. DOT-TST-76-49 (National Bureau

of Standards, Washington, D. C. , October 1975).

[3] Kilmer, R. D. , Cadoff, M. A., Mathews, D. E. , and Shoemaker, Jr., C.

0. , Effects of Load, Inflation Pressure and Tire Deflection on Truck

Tire Noise Levels, U. S. Department of Transportation Report No. DOT

HS-803 874 (National Bureau of Standards, Washington, D. C. , December

1978).

[4] Gallaway, B. M. , and Rose, J. G., Macrotexture, Friction, Cross Slope,

and Wheeltrack Depression Measurements on 41 Typical Texas Highway

Pavements, Research Report 138-2 (Texas Transportation Institute, Texas

A&M University, Bryan, Texas, 1970).

[5] American Society for Testing and Materials, D 2240-75, Standard

Methods of Test for Indentation Hardness of Rubber and Plastics by

Means of a Durometer , in Part 37, Book of ASTM Standards, 1978 (ASTM,

Philadelphia, Pa.).

[6] Anon., The 1978 Yearbook (Tire and Rim Association, Inc., Akron, Ohio,

1978)

.

[7] SAE Recommended Practice J57a, Sound Level of Highway Truck Tires

(Society of Automotive Engineers, Inc., Warrendale, Pa., 1978).

[8] American National Standard Si. 4-1971, Specification for Sound Level

Meters (American National Standards Institute, Inc., New York, N.Y.,

1971).

[9] Anon., Truck Noise-1, Peak A-Weighted Sound Levels Due to Truck Tires,

U. S. Department of Transportation Report No. OST-ONA-71-9 (National

Bureau of Standards, Washington, D. C. , September 1970).

[10]

Leasure, Jr., W. A., Corley, D. M. , Flynn, D. R. , and Forrer, J. S.,

Addendum to Truck Noise-1, Peak A-Weighted Sound Levels Due to Truck

Tires, U. S. Department of Transportation Report No. OST/TST-72-1

(National Bureau of Standards, Washington, D. C., July 1972).

34
[11] Leasure, Jr., W. A., Mathews, D. E. , and Rinkinen, W. J., Truck Noise

1-A, Noise Evaluation Tests of Military Truck Tires, U. S. Department

of Transportation Report No. DOT-TST-74-21 (National Bureau of Standards,

Washington, D. C., February 1974).

[12] Kilmer, R. D. , Leasure, Jr., W. A., Corley, D. M. , Mathews, D. E., and

Shoemaker, Jr., C. 0., Truck Noise 1-D, Empirical Model for Predicting

In-Service Truck Tire Noise Levels, U. S. Department of Transportation

Report DOT-TST-76T-5 (National Bureau of Standards, Washington, D.C.

July 1976)

.

[13] Kilmer, R. D., Test Procedures for Future Tire Noise Regulations, SAE

Paper 762034, published in SAE Publication P-70: SAE Highway Tire Noise

Symposium Proceedings, San Francisco, California, November 10-12, 1976.

[14] Thruman, G. R. , and Leasure, Jr., W. A. (editors). Noise and Traction

Characteristics of Bias-Ply and Radial Tires for Heavy Duty Trucks, DOT

Report No. DOT-TST-78-2 (U. S. Department of Transportation,

Washington, D. C., October 1977).

[15] Hillquist, R. K. , and Carpenter, P. C., A Basic Study of Automobile Tire

Noise, presented at the 85th meeting of the Acoustical Society of

America, Boston, Mass., April 1973.

35
6 . ACKNOWLEDGEMENTS

The author would like to recognize the contributions made by the

following people who have greatly aided this program: the staff of the

Texas Transportation Institute, especially Mr. A. J. Stocker and

Mr. T. Junek for assistance in conducting the field tests; Mr. J. Cornelius

of Kelly-Springfield Tire Company and Mr. R. Anderson of Garrett

Freightlines, Inc. for the loan of test tires.

The author also exresses appreciation to the NBS staff who worked on

this project: Mr. D. E. Mathews and Mr. C. 0. Shoemaker, Jr. for assistance

in conducting the field tests, Mr. R. L. Fisher and Mr. D. M. Corley for

assisting in data reduction and analysis, Mrs. A. T. Rothgeb and

Mrs. D. A. Neal for typing and preparation of the manuscript, and Mr.

W. A. Leasure, Jr. of the U. S. Department of Transportation for review of

the report.

36
NBS-1I4A rev. 9-7o

U.S. DEPT. OF COMM. NoJ 5. Recipient * Acetssim No, BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO.

NBSIR 79-1750 (R)

4. TITLE AND SUBTITLE

Investigation of the Noise Generated by "Quiet" Design

Bias-Ply and Radial Truck Tires with Cross-Bar Tread

Patterns

5. Publication Date May 1979

7. AUTHORi Si Roger D. Kilmer

8. Performing Organ. Report No. NBSIR 79-1750 (R)

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF commerce

WASHINGTON, DC 20234

t* Unit No.

11. Contract/Grant No. DOT-HS-8-01976

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, ZIP) U. S. Department of Transportation

National Highway Traffic Safety Administration

Office of Heavy Duty Vehicle Research

Washington, D. C. 20590

13. Type of Report & Period Covered

FINAL

15. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16. ABSTRACT (A 200-word or leas factual summary of moat significant information. If document includes a significant bibliography or

literature survey, mention it here.) Recent advances in the development of heavy duty truck tires has lead to the introduction of "quiet" design bias-ply cross-bar tires, as well as radial tires with

cross-bar tread patterns. To adequately assess the noise/saf ety/economic tradeoffs,

acoustic data on a representative sample of these newer tire designs are essential.

This report presents acoustic data measured at 50 feet for one type of new "quiet"

design bias-ply and seven types of radial cross-bar tires (both new and worn) for

coastbys at 50 mph on three pavement surfaces—asphalt, concrete and Jennite. In

general, the data show that these newer tire designs generate lower sound levels than

conventional bias-ply cross-bar truck tires. The differences in sound level between

these newer designs and conventional bias-ply cross-bars vary widely and are a function

of the individual tire and state of tread wear. These data show that the sound level

is dependent on pavement surface with a rank ordering of asphalt (the lowest sound

levels), concrete and Jennite. Also, it is shown for the radial cross-bar tires that,

depending upon the particular tire, the sound level increases with tread wear from

0.8 to 9.0 dB on the asphalt and concrete pavements.

17. KEY WORDS ( six to twelve entries; alphabetical order; capitalize only the lirst letter of the lirat key word unless a proper name;

separated by semicolons

)

Acoustics; noise measurement; noise (sound); tire noise; transportation noise; truck.

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