ASTM F2779-10
(Practice)Standard Practice for Commercial Radial Truck-Bus Tires to Establish Equivalent Test Severity Between a 1.707-m (67.23-in.) Diameter Roadwheel and a Flat Surface
Standard Practice for Commercial Radial Truck-Bus Tires to Establish Equivalent Test Severity Between a 1.707-m (67.23-in.) Diameter Roadwheel and a Flat Surface
SIGNIFICANCE AND USE
Historically, tires have been tested for endurance by a variety of test methods. Some typical testing protocols have been: (1) proving grounds or highway testing over a range of speeds, loads, and inflations, (2) testing on fleets of vehicles for extended periods of time, and (3) indoor (laboratory) testing of tires loaded on a rotating 1.707-m diameter roadwheel; however, the curved surface of a 1.707-m diameter roadwheel results in a significantly different tire behavior from that observed on a flat or highway surface.
This practice addresses the need for providing equivalent test severity over a range of typical tire operating conditions between a 1.707-m diameter roadwheel surface (Practice F551) and a flat surface. There are different deformations of the tire footprint on curved versus flat surfaces resulting in different footprint mechanics, stress/strain cycles, and significantly different internal operating temperatures for the two types of contact surface. Since tire internal temperatures are key parameters influencing tire endurance or operating characteristics under typical use conditions, it is important to be able to calculate internal temperature differentials between curved and flat surfaces for a range of loads, inflation pressures and rotational velocities (speeds).
Data from lab and road tire temperature measurement trials were combined, statistically analyzed, and tire temperature prediction models derived.
The fit of the models to the data is shown as the coefficient of determination, R2, for the two critical crown area temperatures, i.e. tread centerline and belt edge, as well as the ply ending area:
R2 = 0.89, 0.90, and 0.89 respectively
These prediction models were used to develop the prediction profilers described in Section 7 and Annex A1.
SCOPE
1.1 This practice describes the procedure to identify equivalent test severity conditions between a 1.707-m diameter laboratory roadwheel surface and a flat or highway surface for commercial radial truck-bus tires.
1.1.1 Tire operational severity, as defined as the running or operational temperature for certain specified internal tire locations, is not the same for these two test conditions. It is typically higher for the laboratory roadwheel at equal load, speed and inflation pressure conditions due to the curvature effect.
1.1.2 The practice applies to specific operating conditions of load range F through L for such commercial radial truck-bus tires.
1.1.3 The specific operating conditions under which the procedures of the practice are valid and useful are completely outlined in Section 6 (Limitations) of this standard.
1.1.4 It is important to note that this standard is composed of two distinct formats:
1.1.4.1 The usual text format as published in this volume of the Book of Standards (Vol 09.02).
1.1.4.2 A special interactive electronic format that uses a special software tool, designated as prediction profilers or profilers. This special profiler may be used to determine laboratory test conditions that provide equivalent tire internal temperatures for the tread centerline, belt edge, or ply ending region for the two operational conditions, that is, the curved laboratory roadwheel and flat highway test surfaces.
1.2 The prediction profilers are based on empirically developed linear regression models obtained from the analysis of a large database that was obtained from a comprehensive experimental test program for roadwheel and flat surface testing of typical commercial truck and bus tires. See Section 7 and References (1, 2) , for more details.
1.2.1 For users viewing the standard on CD-ROM or PDF, with an active and working internet connection, the profilers can be accessed on the ASTM website by clicking on the links in 7.5 and 7.6.
1.2.2 For users viewing the standard in a printed format, the profilers can be accessed by entering the links to the ASTM website in 7.5 and 7.6 into their inte...
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Designation: F2779 − 10
StandardPractice for
Commercial Radial Truck-Bus Tires to Establish Equivalent
Test Severity Between a 1.707-m (67.23-in.) Diameter
1
Roadwheel and a Flat Surface
This standard is issued under the fixed designation F2779; 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 typical commercial truck and bus tires. See Section 7 and
2,3
References (1, 2) for more details.
1.1 This practice describes the procedure to identify equiva-
1.2.1 For users viewing the standard on CD-ROM or PDF,
lent test severity conditions between a 1.707-m diameter
with an active and working internet connection, the profilers
laboratory roadwheel surface and a flat or highway surface for
can be accessed on theASTM website by clicking on the links
commercial radial truck-bus tires.
in 7.5 and 7.6.
1.1.1 Tire operational severity, as defined as the running or
1.2.2 For users viewing the standard in a printed format, the
operational temperature for certain specified internal tire
profilers can be accessed by entering the links to the ASTM
locations, is not the same for these two test conditions. It is
website in 7.5 and 7.6 into their internet browsers.
typically higher for the laboratory roadwheel at equal load,
1.3 For this standard, SI units shall be used, except where
speed and inflation pressure conditions due to the curvature
indicated.
effect.
1.1.2 Thepracticeappliestospecificoperatingconditionsof 1.4 This standard does not purport to address all of the
load range F through L for such commercial radial truck-bus safety concerns, if any, associated with its use. It is the
tires. responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1.3 The specific operating conditions under which the
bility of regulatory limitations prior to use.
procedures of the practice are valid and useful are completely
outlined in Section 6 (Limitations) of this standard.
2. Referenced Documents
1.1.4 Itisimportanttonotethatthisstandardiscomposedof
4
2.1 ASTM Standards:
two distinct formats:
F538 Terminology Relating to the Characteristics and Per-
1.1.4.1 The usual text format as published in this volume of
formance of Tires
the Book of Standards (Vol 09.02).
F551 Practice for Using a 67.23-in. (1.707-m) Diameter
1.1.4.2 A special interactive electronic format that uses a
Laboratory Test Roadwheel in Testing Tires
special software tool, designated as prediction profilers or
IEEE/ASTM SI 10 American National Standard for Use of
profilers. This special profiler may be used to determine
theInternationalSystemofUnits(SI):TheModernMetric
laboratory test conditions that provide equivalent tire internal
System
temperatures for the tread centerline, belt edge, or ply ending
region for the two operational conditions, that is, the curved
3. Terminology
laboratory roadwheel and flat highway test surfaces.
3.1 Definitions:
1.2 The prediction profilers are based on empirically devel-
3.1.1 belt edge (BE) temperature, n— in the cross section of
oped linear regression models obtained from the analysis of a
a radial tire, the temperature at the edge of the stabilizer
large database that was obtained from a comprehensive experi-
(working, widest) plies or belts, for example, in the rubber
mental test program for roadwheel and flat surface testing of
region of the belt edges.
2
The boldface numbers in parentheses refer to the list of references at the end of
this standard.
3
Supporting data have been filed at ASTM International Headquarters and may
1
This practice is under the jurisdiction ofASTM Committee F09 on Tires and is be obtained by requesting Research Report RR:F09-1002.
4
the direct responsibility of Subcommittee F09.30 on Laboratory (Non-Vehicular) For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Testing. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved April 1, 2010. Published May 2010. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F2779-10. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F2779 − 10
3.1.2 contained air temperature, n—the temperature of the 3.1.17 tire, radial, n—a pneumatic tire in which the ply
air contained within the tire cavity when the tire is mounted cordsthatextendtothebeadsarelaidsubstantiallyat90°tothe
and inflated on the proper rim. center line of the tread, the tire being stabi
...
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