ASTM F408-99(2015)

Standard Test Method for Tires for Wet Traction in Straight-Ahead Braking, Using a Towed Trailer

SIGNIFICANCE AND USE
5.1 The measured values are traction properties of tires obtained with the towed trailer described here on a given road surface, under given environmental conditions (ambient and road surface temperature, humidity, wind speed and direction, purity and film depth of water used to wet the road surface). They are carried out in accordance with the stated test procedures and reflect the performance of the total tire-vehicle environmental system. A change in any of these factors may change the measurements on a subsequent run of the test.  
5.2 These test methods are suitable for research and development purposes, where tires are compared during a single series of tests. They may not be suitable for regulatory statutes or specification acceptance, because the values obtained may not necessarily agree or correlate either in rank order or absolute traction performance level with those obtained on other road surfaces (or the same surface after additional wear), under other environmental conditions, or other towed trailers, or other test devices, or with results obtained with other test procedures.
SCOPE
1.1 This test method covers the measurement of braking traction of tires designed for passenger cars or light trucks. Such braking traction measurements are applicable to conditions wherein the vehicle is traveling straight ahead on a wet, paved surface.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Apr-2015
• ICS: 83.160.10 - Road vehicle tyres
• Technical Committee: F09 - Tires
• Drafting Committee: F09.20 - Vehicular Testing

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F408 − 99 (Reapproved 2015)
Standard Test Method for
Tires for Wet Traction in Straight-Ahead Braking, Using a
1
Towed Trailer
ThisstandardisissuedunderthefixeddesignationF408;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 braking force, [F], n—of a tire, the negative longitu-
dinal force resulting from braking torque application. F538
1.1 This test method covers the measurement of braking
traction of tires designed for passenger cars or light trucks.
3.1.2 braking force coeffıcient, n—of a tire, the ratio of
Such braking traction measurements are applicable to condi-
braking force to normal force. F538
tions wherein the vehicle is traveling straight ahead on a wet,
3.1.3 braking force coeffıcient, peak, n—of a tire, the maxi-
paved surface.
mum value of tire braking force coefficient that occurs prior to
1.2 The values stated in SI units are to be regarded as the
wheel lockup as the braking torque is progressively increased.
standard. The values given in parentheses are for information
F538
only.
3.1.4 braking force coeffıcient, slide, n—of a tire, the value
1.3 This standard does not purport to address all of the
of braking force coefficient obtained on a locked wheel. F538
safety concerns, if any, associated with its use. It is the
2 2
3.1.5 braking torque, [ML /T ], n—of a vehicle, the
responsibility of the user of this standard to establish appro-
negative wheel torque. F538
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
3.1.6 lockup, n—of a wheel, the condition of a wheel in
which its rotational velocity about the wheel spin axis is zero
2. Referenced Documents
and it is prevented from rotating in the presence of applied
2
2.1 ASTM Standards:
wheel torque.
E274Test Method for Skid Resistance of Paved Surfaces
3.1.7 longitudinal force, [F], n—of a tire, the component of
Using a Full-Scale Tire
the tire force vector in the X' direction. F538
E1337Test Method for Determining Longitudinal Peak
Braking Coefficient of Paved Surfaces Using Standard 3.1.8 normal force, [F], n—of a tire,thecomponentofatire
Reference Test Tire force vector in the Z' direction. F538
F377PracticeforCalibrationofBraking/TractiveMeasuring
3.1.9 skid number (SN), n—slide braking force coefficient
Devices for Testing Tires
multiplied by 100. F538
F457Test Method for Speed and Distance Calibration of
3.1.10 test run, n—asinglepassofaloadedtireoveragiven
Fifth Wheel Equipped With Either Analog or Digital
test surface. F538
Instrumentation
F538Terminology Relating to the Characteristics and Per-
3.1.11 tire axis system, n—the origin of the tire-axis system
formance of Tires
is the center of the tire contact where the X'-axis is the
F1650Practice for Evaluating Tire Traction Performance
intersection of the wheel plane and the road plane with a
Data Under Varying Test Conditions
positive direction forward, the Z'-axis is perpendicular to the
road plane with a positive direction downward, and theY'-axis
3. Terminology
isintheroadplane,itsdirectionbeingchosentomaketheaxis
3.1 Definitions:
system orthogonal and right-hand.
3.1.11.1 Discussion—See Fig. 1. F538
1
This test method is under the jurisdiction of ASTM Committee F09 on Tires
and is the direct responsibility of Subcommittee F09.20 on Vehicular Testing. 3.1.12 tire forces, [F], n—theexternalforcesactingonatire
Current edition approved May 1, 2015. Published June 2015. Originally
by the road. F538
approved in 1975. Last previous edition approved in 2008 as F408–99 (2008).
DOI: 10.1520/F0408-99R15. 3.1.13 torque, [FL], n—of a wheel, the external torque
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
applied to a tire from a vehicle about the wheel spin axis.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.1.13.1 Discussion—Driving torque is positive wheel
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. torque; braking torque is negative wheel torque. F538
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F408 − 99 (2015)
6.2 Tow Vehicle:
6.2.1 Thetowvehicleshallhavethecapabilityoftowingthe
trailer at specified speeds in the range from 32 to 96 km/h (20
to 60 mph), which are to be kept constant to within 0.8 km/h
(0.5 mph), even at maximum level of application of braking
forces.
6.2.2 The tow vehicle shall be equipped with the following
accessories:
6.2.2.1 Equipment to actuate brakes on towed trai
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F408 − 99 (Reapproved 2008) F408 − 99 (Reapproved 2015)
Standard Test Method for
Tires for Wet Traction in Straight-Ahead Braking, Using a
1
Towed Trailer
This standard is issued under the fixed designation F408; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the measurement of braking traction of tires designed for passenger cars or light trucks. Such
braking traction measurements are applicable to conditions wherein the vehicle is traveling straight ahead on a wet, paved surface.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E274 Test Method for Skid Resistance of Paved Surfaces Using a Full-Scale Tire
E1337 Test Method for Determining Longitudinal Peak Braking Coefficient of Paved Surfaces Using Standard Reference Test
Tire
F377 Practice for Calibration of Braking/Tractive Measuring Devices for Testing Tires
F457 Test Method for Speed and Distance Calibration of Fifth Wheel Equipped With Either Analog or Digital Instrumentation
F538 Terminology Relating to the Characteristics and Performance of Tires
F1650 Practice for Evaluating Tire Traction Performance Data Under Varying Test Conditions
3. Terminology
3.1 Definitions:
3.1.1 braking force, [F], n—of a tire, the negative longitudinal force resulting from braking torque application. F538
3.1.2 braking force coeffıcient, n—of a tire, the ratio of braking force to normal force. F538
3.1.3 braking force coeffıcient, peak, n—of a tire, the maximum value of tire braking force coefficient that occurs prior to wheel
lockup as the braking torque is progressively increased. F538
3.1.4 braking force coeffıcient, slide, n—of a tire, the value of braking force coefficient obtained on a locked wheel. F538
2 2
3.1.5 braking torque, [ML /T ], n—of a vehicle, the negative wheel torque. F538
3.1.6 lockup, n—of a wheel, the condition of a wheel in which its rotational velocity about the wheel spin axis is zero and it
is prevented from rotating in the presence of applied wheel torque.
3.1.7 longitudinal force, [F], n—of a tire, the component of the tire force vector in the X' direction. F538
3.1.8 normal force, [F], n—of a tire, the component of a tire force vector in the Z' direction. F538
3.1.9 skid number (SN), n—slide braking force coefficient multiplied by 100. F538
3.1.10 test run, n—a single pass of a loaded tire over a given test surface. F538
1
This test method is under the jurisdiction of ASTM Committee F09 on Tires and is the direct responsibility of Subcommittee F09.20 on Vehicular Testing.
Current edition approved May 1, 2008May 1, 2015. Published June 2008June 2015. Originally approved in 1975. Last previous edition approved in 19992008 as
F408 – 99.F408 – 99 (2008). DOI: 10.1520/F0408-99R08.10.1520/F0408-99R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F408 − 99 (2015)
3.1.11 tire axis system, n—the origin of the tire-axis system is the center of the tire contact where the X'-axis is the intersection
of the wheel plane and the road plane with a positive direction forward, the Z'-axis is perpendicular to the road plane with a positive
direction downward, and the Y'-axis is in the road plane, its direction being chosen to make the axis system orthogonal and
right-hand.
3.1.11.1 Discussion—
See Fig. 1. F538
3.1.12 tire forces, [F], n—the external forces acting on a tire by the road. F538
3.1.13 torque, [FL], n—of a wheel, the external torque applied to a tire from a vehicle about the wheel spin axis.
3.1.13.1 Discussion—
Driving torque is positive whe
...