ASTM F1650-98

Standard Practice for Evaluating Tire Traction Performance Data Under Varying Test Conditions

SCOPE
1.1 This practice covers the required procedures for examining sequential control tire data for any variation due to changing test conditions. Such variations may influence absolute and also comparative performance of candidate tires, as they are tested over any short or extended time period. The variations addressed in this practice are systematic or bias variations and not random variations. See Appendix X1 for additional details.  
1.1.1 Two types of variation may occur: time or test sequence "trend variations," either linear or curvilinear, and the less common transient or abrupt shift variations. If any observed variations are declared to be statistically significant, the calculation procedures are given to correct for the influence of these variations. This approach is addressed in Method A.  
1.2 In some testing programs, a policy is adopted to correct all candidate traction test data values without the application of a statistical routine to determine if a significant trend or shift is observed. This option is part of this practice and is addressed in Method B.  
1.3 The issue of rejecting outlier data points or test values that might occur among a set of otherwise acceptable data values obtained under identical test conditions in a short time period is not part of this practice. Specific test method or other outlier rejection standards that address this issue may be used on the individual data sets prior to applying this practice and its procedures.  
1.4 Although this practice applies to various types of tire traction testing (for example, dry, wet, snow, ice), the procedures as given in this practice may be used for any repetitive tire testing in an environment where test conditions are subject to change.  
1.5 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: 09-Jun-1998
• ICS: 83.160.10 - Road vehicle tyres
• Technical Committee: F09 - Tires
• Drafting Committee: F09.20 - Vehicular Testing

Relations

• Replaced By: ASTM F1650-98(2005) - Standard Practice for Evaluating Tire Traction Performance Data Under Varying Test Conditions
• Effective Date: 01-Nov-2005
• Referred By: ASTM F1649-20 - Standard Test Methods for Evaluating Wet Braking Traction Performance of Passenger Car Tires on Vehicles Equipped with Anti-Lock Braking Systems
• Effective Date: 10-Jun-1998
• Referred By: ASTM F408-21 - Standard Test Method for Tires for Wet Traction in Straight-Ahead Braking, Using a Towed Trailer
• Effective Date: 10-Jun-1998
• Referred By: ASTM F1805-20 - Standard Test Method for Single Wheel Driving Traction in a Straight Line on Snow- and Ice-Covered Surfaces
• Effective Date: 10-Jun-1998
• Referred By: ASTM F1572-21 - Standard Test Methods for Tire Performance Testing on Snow and Ice Surfaces
• Effective Date: 10-Jun-1998
• Referred By: ASTM F1806-21 - Standard Practice for Tire Testing Operations–Basic Concepts and Terminology for Reference Tire Use
• Effective Date: 10-Jun-1998

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: F 1650 – 98
Standard Practice for
Evaluating Tire Traction Performance Data Under Varying
Test Conditions
This standard is issued under the fixed designation F1650; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Tiretractiontestingprogramsatprovinggroundsorotherexteriortestsitesareoftenextendedover
a period of days or weeks. During this time period test conditions may change due to a number of
varying factors, for example, temperature, rain or snow fall, surface texture, water depth, and wind
velocity and direction. If tire performance comparisons are to be made over any part of the test
program(ortheentireprogram)wherethesetestconditionvariationsareknownorsuspectedtoaffect
performance, the potential influence of these variations must be considered in any final evaluation of
traction performance.
1. Scope 1.4 Although this practice applies to various types of tire
traction testing (for example, dry, wet, snow, ice), the proce-
1.1 This practice covers the required procedures for exam-
dures as given in this practice may be used for any repetitive
ining sequential control tire data for any variation due to
tire testing in an environment where test conditions are subject
changing test conditions. Such variations may influence abso-
to change.
lute and also comparative performance of candidate tires, as
1.5 This standard does not purport to address all of the
they are tested over any short or extended time period. The
safety concerns, if any, associated with its use. It is the
variations addressed in this practice are systematic or bias
responsibility of the user of this standard to establish appro-
variations and not random variations. See Appendix X1 for
priate safety and health practices and determine the applica-
additional details.
bility of regulatory limitations prior to use.
1.1.1 Two types of variation may occur: time or test
sequence“trendvariations,”eitherlinearorcurvilinear,andthe
2. Referenced Documents
less common transient or abrupt shift variations. If any
2.1 ASTM Standards:
observed variations are declared to be statistically significant,
E501 Specification for Standard Rib Tire for Pavement
thecalculationproceduresaregiventocorrectfortheinfluence
Skid-Resistance Tests
of these variations. This approach is addressed in Method A.
E524 Specification for Standard SmoothTire for Pavement
1.2 In some testing programs, a policy is adopted to correct
Skid-Resistance Tests
allcandidatetractiontestdatavalueswithouttheapplicationof
E826 PracticeforTestingHomogeneityofMaterialsforthe
astatisticalroutinetodetermineifasignificanttrendorshiftis
Development of Reference Materials
observed. This option is part of this practice and is addressed
E1136 Specification for a Radial Standard Reference Test
in Method B.
Tire
1.3 The issue of rejecting outlier data points or test values
F538 Terminology Relating to the Characteristics and Per-
that might occur among a set of otherwise acceptable data
formance of Tires
values obtained under identical test conditions in a short time
period is not part of this practice. Specific test method or other
3. Terminology
outlier rejection standards that address this issue may be used
3.1 Descriptions of Terms Specific to This Standard—
ontheindividualdatasetspriortoapplyingthispracticeandits
Descriptionsoftermsparticulartothispracticearelistedeither
procedures.
as principal terms or under principal terms as derived terms.
This practice is under the jurisdiction ofASTM Committee F-9 onTires and is
Annual Book of ASTM Standards, Vol 04.03.
the direct responsibility of Subcommittee F09.20 on Vehicular Testing.
Annual Book of ASTM Standards, Vol 03.06.
Current edition approved Mar. 10, 1998. Published October 1998. Originally
published as F1650-95. Last previous edition F1650-95. Annual Book of ASTM Standards, Vol 09.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1650–98
3.1.1 Discussion—The terminology in this section is cur- 5.2 Using control tire average measured performance pa-
rently under review by Subcommittee F09.94 on Terminology. rameters, the performance parameters of the candidate tires
Thisterminologyissubjecttochangeandshouldbeconsidered (sets) are corrected for any changes in test conditions. Two
tentative. correction procedures are described (MethodAand Method B)
3.1.2 test, n—a technical procedure performed on an object that use different reference points for data correction and as
(or set of objects) using specified equipment, that produces such give different values for the corrected actual or absolute
data; the data are used to evaluate or model selected properties traction parameters. However, both test methods give the same
or characteristics of the object (or set of objects). relativeratingsortractionperformanceindexes.SeeSection10
3.1.3 test tire, n—a tire used in a test. formoredetails.Thetwotestmethodsaresummarizedinmore
3.1.4 test tire set, n—one or more tires, as required by the detail in Section 6 and Section 9. Both MethodsAand B have
test equipment or procedure, to perform a test, producing a advantages and disadvantages.
single set of results; these tires are usually nominally identical. 5.2.1 Method A uses the initial operational conditions de-
3.1.5 candidate tire (set), n—a test tire (or test tire set) that fined by the first control traction test as a reference point. The
is part of an evaluation program; each candidate tire (set) calculations correct all traction test performance parameters
usually has certain unique design or other features that distin- (for example, traction coefficients) to the initial level or
guish it from other candidate tires in the program. condition of the pavement or other testing conditions, or both.
3.1.6 reference tire (set), n—a special test tire (test tire set) With this test method, corrections may be made after only a
that is used as a benchmark in an evaluation program; these few candidate and control sets have been evaluated.
tires usually have carefully controlled design features to 5.2.2 Method B uses essentially the midpoint of any evalu-
minimize variation. ation program, with the grand average traction test value as a
3.1.7 control tire (set), n—a reference tire (or reference set) reference point. This grand average value is obtained with
repeatedly tested in a specified sequence throughout an evalu- higher precision than the initial control traction test average of
ation program, that is used for data adjustment or statistical MethodA, since it contains more values. However, Method B
procedures, or both, to offset or reduce testing variation and corrections cannot be made until the grand average value is
improve the accuracy of candidate tire (set) evaluation or established, which is normally at the end of any program.
detect test equipment variation, or both. 5.3 Annex A1 provides illustrations of several types of
3.1.8 surface monitoring tire (set), n—a reference tire (or typical variation patterns for control tire data. It additionally
reference set), used to evaluate changes in the test surface over provides an example of the Method A correction calculations
a selected time period. required to evaluate a set of candidate test tires. Method B
3.1.9 standard reference test tire, SRTT, n—atirethatmeets corrections follow the same general approach as illustrated in
the requirements of Specification E1136, commonly used as a Annex A1, with C used in place of C1.
avg
control tire or surface monitoring tire. 5.4 Annex A2 provides a recommended technique for
3.1.10 test run, n—in tire testing, a single pass (over a test weighting the correction of the two or three candidate values
surface) or sequence of data acquisition, or both, in the act of (for example, T1, T2, T3) between each pair of control values.
testing a tire or tire set under selected test conditions. This gives a slightly improved correction that may be impor-
3.1.11 traction test, n—in tire testing, a series of n test runs tant in certain testing operations.
at a selected operational condition; a traction test is character- 5.5 Appendix X1 provides a statistical model for the trac-
ized by an average value for the measured performance tion measurement process. This may help the user of this
parameter. practice to sort out the differences between fixed or bias
components of variation and random components of variation.
4. Significance and Use
AppendixX1givesarationalefortheproceduresasoutlinedin
4.1 Tire testing is conducted to make technical decisions on
this practice.
variousperformancecharacteristicsoftires,andgoodtechnical
5.6 AnnexA2 contains some background and details on the
decisions require high quality test data. High quality test data
propagation of error or test variation that occurs when correc-
are obtained with carefully designed and executed tests.
tions are applied to the measured traction performance param-
However, even with the highest quality testing programs,
eters and when traction performance indexes are calculated.
unavoidabletimeortestsequencetrendsorotherperturbations
METHOD A—DATA CORRECTIONS BASED ON
may occur. The procedures as described in this practice are
INITIAL CONTROL TRACTION TEST
therefore needed to correct for these unavoidable testing
complications.
6. Summary of Method A
5. Summary of Practice
6.1 This method corrects the data obtained throughout the
5.1 This practice specifies certain test plans for testing evaluation program to the initial conditions (test surface or
control tires. Testing begins with an initial test of the control other, or both)“ reference point” at the beginning of the
tireortireset.Anumberofcandidatetiretractiontestsarethen program.The correction procedure (and calculation algorithm)
conducted followed by a repeat test of the control tire traction for time trend variations is mathematically equivalent to that
test. Additional candidate traction tests are conducted prior to described in Practice E826. The procedure used for abrupt or
the next control tire traction test. This sequential procedure is step changes is provisional and is subject to change as
repeated for the entire evaluation program. experience is gained. In this method the initial traction test
F1650–98
value for the control tire is a key data point. This method also the extent that it ceases to function as a stable control. In such
allows for decisions on the need for any correction, based on a situations it is necessary to use more than one control tire
statistical analysis of the control tire data. throughoutanyevaluationprogram.Insuchcasesacontroltire
indicationschemesuchasC1-1,C1-2,C1-3,C2-4,C2-5,C2-6,
7. Procedure
C3-1, etc, is suggested. In this scheme, C1-1=control tire 1,
7.1 Thetestprocedureisgivenintermsoftestingtiresetsof sequence use 1; C1-2=control tire 1, sequence use 2; .,
C2-4=control tire 2, sequence use 4, etc.
four tires, that is, one tire on each of four vehicle positions. If
only one tire is to be tested (trailer or other dynamometer 7.5 Table of Results—Prepare a table of test results and
vehicle testing), follow the procedure as outlined with the record all data with columns for:
understanding that the one tire replaces the tire set.
7.5.1 Test sequence number, a sequential indication from 1
7.2 Assemble all the tire sets to be tested in any evaluation to m, of all the tests for any program of evaluation,
program or for daily testing. Select the test speeds to be used
7.5.2 Tire set identification,
and other operational test conditions as well as the order in
7.5.3 Speed or other selected operational test condition(s),
which the candidate tire sets are to be tested.
and
7.2.1 For any selected order, a test plan is established with
7.5.4 Average value (for n test runs) for the measured
referencetire(s)designatedasacontroltiresettestedatregular
parameter for that operational condition.
intervals among the selected candidate sets. Select the number
7.6 Both control and candidate set data shall be included in
oftestrunsorreplicatesforbothcontrolandcandidatetiresets.
the table in the order as tested. If deemed important, a separate
Acomplete test for a tire set is defined as the total of p traction
table of ambient temperature, wind direction, wind velocity, or
tests, one at each selected operational test condition, with n
other weather information also shall be prepared on a selected
replicate test runs for each operational condition (for example,
time (hourly) basis.
speed and surface type).
7.2.2 Tests with a surface monitoring tire may also be
8. Calculations for Corrected Traction Performance Data
conducted on a regular basis in addition to the control tire.
8.1 Preliminary Control Set Data Review—The decision to
7.3 Test Sequence—The control tires may be standard tires
correct data, for any part of the test program where candidate
as specified in Specifications E501, E524, and E1136, or a
set comparisons are to be made, is based on the time or test
tiresetsimilarindesignandperformanceleveltothecandidate
sequenceresponseofthecontroltireparametersforeachspeed
sets. Conduct a complete test for the control sets in relation to
or other selected operational test condition. Corrections may
thecandidatesetsasgiveninTable1.Twotestplansaregiven:
also be made for the entire test program. If a significant trend
Plan A, in which (excluding the initial control set) candidate
is found or if significant transient perturbations are found,
tires constitute 67% of the tires tested, and Plan B, in which
corrections are made for candidate set traction performance
candidate tires constitute 75% of the tires tested.
parameters.
7.4 Number of Test Runs at Each Speed or Operational
8.2 Evaluating the Control Tire Data—Using the data
Condition—The number of test runs or replicates, n, for each
table(s) generated in accordance with the procedures outlined
speed or other selected operational condition for each candi-
in 7.5, plot the average control tire traction test parameter (that
date tire set and each control set, except the first set, shall be
is, for C1 to Ci) at each speed or other operational condition,
selected. The number of test runs depends on the test method.
as a function of the test sequence number for the control set or
Good testing procedure calls for as many test runs as possible.
the “test time” period (hours) that has elapsed for each control
If direction of test is important on any
...