ASTM F2869-10

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Designation: F2869 − 10
StandardPractice for
Radial Light Truck Tires to Establish Equivalent Test
Severity Between a 1.707-m (67.23-in.) Diameter Rotating
Roadwheel and a Flat Surface
This standard is issued under the fixed designation F2869; 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 radial light truck (LT) tires. See Section 7 and the
research report 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
radial pneumatic light truck (LT) 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.
1.4 This standard does not purport to address all of the
1.1.2 Thepracticeappliestospecificoperatingconditionsof
light truck tires up through load range E for such tires used on safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
vehicles having a gross vehicle weight rating (GVWR) ≤4536
kg (10000 lb). priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1.3 The specific operating conditions under which the
procedures of the practice are valid and useful are completely
2. Referenced Documents
outlined in Section 6, (Limitations) of this standard.
1.1.4 Itisimportanttonotethatthisstandardiscomposedof
2.1 ASTM Standards:
two distinct formats:
F414 Test Method for Energy Absorbed by a Tire When
Deformed by Slow-Moving Plunger
1.1.4.1 The usual text format as published in this volume of
F538 Terminology Relating to the Characteristics and Per-
the Book of Standards (Vol. 09.02).
formance of Tires
1.1.4.2 A special interactive electronic format that uses a
F551 Practice for Using a 67.23-in. (1.707-m) Diameter
special software tool, designated as prediction profilers or
Laboratory Test Roadwheel in Testing Tires
profilers. This special profiler may be used to determine
F1922 Test Method for Tires, Pneumatic, Vehicular, High-
laboratory test conditions that provide equivalent tire internal
way
temperatures for the belt edge region for the two operational
F2779 Practice for Commercial Radial Truck-Bus Tires to
conditions, that is, the curved laboratory roadwheel and flat
Establish Equivalent Test Severity Between a 1.707-m
highway test surfaces.
(67.23-in.) Diameter Roadwheel and a Flat Surface
1.2 The prediction profilers are based on empirically devel-
IEEE/ASTM SI 10 American National Standard for Use of
oped linear regression models obtained from the analysis of a
theInternationalSystemofUnits(SI):TheModernMetric
large database that was obtained from a comprehensive experi-
System
mental test program for roadwheel and flat surface testing of
Supporting data have been filed at ASTM International Headquarters and may
This practice is under the jurisdiction ofASTM Committee F09 on Tires and is be obtained by requesting Research Report RR: F09-1002.
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 Oct. 1, 2010. Published January 2011. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F2869-10. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2869 − 10
3. Terminology 3.1.15 tire, pneumatic, n—a hollow tire that becomes load-
bearing upon inflation with air, or other gas, to a pressure
3.1 Definitions:
above atmospheric. F538
3.1.1 belt edge (BE) temperature, n— in the cross section of
3.1.16 tire, radial, n—a pneumatic tire in which the ply
a radial tire, the temperature at the edge of the stabilizer plies
cordsthatextendtothebeadsarelaidsubstantiallyat90°tothe
orbelts,forexample,intherubberregionofthetwobeltedges.
center line of the tread, the tire being stabilized by a belt. F538
3.1.2 contained air temperature, n—the temperature of the
3.1.17 tire speed rating, n—the maximum speed for which
air contained within the tire cavity when the tire is mounted
the use of the tire is rated under certain conditions as
and inflated on the proper rim.
designated by the speed symbol marked on the tire sidewall or
3.1.3 curved equivalent test severity, n—in tire testing, the
maximum speed rating as determined by the manufacturer.
test conditions (load, rotational speed, tire inflation pressure)
3.1.18 tire test speed, n—the tangential speed at the point of
on the flat or highway surface that will provide equivalent
contact with the road curved surface of a rotating tire for
internal tire temperatures, for example, at the belt edge, to a
evaluation purposes.
known set of curved 1.707-m roadwheel surface test condi-
tions.
4. Summary of Practice
3.1.4 endurance, n—of a tire, the ability of a tire to perform
4.1 This practice provides a procedure to determine the
as designed in its intended usage conditions such as load,
1.707-m diameter roadwheel tire test conditions (speed, load,
inflation pressure, speed, time, and environmental conditions.
and inflation pressure) for flat surface equivalent test severity.
3.1.5 high speed performance, n—of a tire, the rotational
It also enables the user to determine the 1.707-m diameter
speed capability of a tire to perform as designed in its intended
roadwheel test conditions for a specific increase or decrease in
usage conditions such as load, inflation pressure, speed, time,
severity with respect to flat surface test severity. The converse
and environmental conditions.
is also true, determining the flat surface test conditions that
provide equal test severity to a selected set of 1.707-m
3.1.6 highway equivalent test severity, n—in tire testing, the
diameter roadwheel test conditions.
test conditions (load, rotational speed, tire inflation pressure)
on the 1.707-m roadwheel that will provide equivalent internal
4.2 This practice provides a prediction profiler procedure
tire temperatures, for example, at the belt edge, to a known set
(see Section 7 and Annex A1) to establish equivalent test
of highway or flat surface conditions.
severity between a 1.707-m diameter rotating wheel (Practice
F551) and a flat surface, by adjusting test speed, load and
3.1.7 light truck tire, n—a tire that has a LT prefix or suffix
inflation pressure. The prediction profiler provides the ability
in the tire size description: this indicates that the tire was
to identify numerous test conditions and resultant belt edge
primarilyintendedforserviceonlighttruckswithgrossvehicle
temperature differentials within the confines of this practice as
weights (GVWR) ≤4536 kg.
described in Section 6.
3.1.8 load range, n—of a light truck tire,aletterdesignation
4.3 Equivalent test severity is defined as the set of test
(B, C, D, E) used to identify a given size tire with its load and
conditions(load,speed,andtireinflationpressure)thatprovide
inflation limits when used in a specific type of service. F414,
equivalent steady state tire internal operating temperatures at
F1922
the belt edge (BE) for: (1) a conversion from flat surface
3.1.9 maximum rated load, n—the load corresponding to a
conditions to a 1.707-m diameter roadwheel conditions or (2)
maximum tire load capacity at the rated inflation pressure in
a conversion from a 1.707-m diameter roadwheel conditions to
accordance with the publications of tire and rim standards
a flat surface conditions.
current at the time of manufacture.
3.1.10 measured inflation pressure, n—gauge pressure of a 5. Significance and Use
tire measured at a given time under ambient temperature and
5.1 Historically, tires have been tested for endurance by a
barometric pressure. F538
variety of test methods. Some typical testing protocols have
3.1.11 rated inflation pressure, n—the minimum cold infla- been: (1) proving grounds or highway testing over a range of
tion pressure specified at the maximum rated load of a tire in speeds,loads,andinflations, (2)testingonfleetsofvehiclesfor
accordance with the publications of tire and rim standards
extended periods of time, and (3) indoor (laboratory) testing of
current at the time of manufacture. tires loaded on a rotating 1.707-m diameter roadwheel;
however, the curved surface of a 1.707-m diameter roadwheel
3.1.12 rim, n—specially shaped circular periphery to which
results in a significantly different tire behavior from that
a tire may be mounted with appropriate bead fitment. F538
observed on a flat or highway surface.
3.1.13 test inflation pressure, n—specifiedgaugepressureof
5.1.1 This practice addresses the need for providing equiva-
a tire mounted on a rim, measured at a given time under
lent test severity over a range of typical tire operating condi-
ambient temperature and barometric pressure for evaluation
tions between a 1.707-m diameter roadwheel surface (Practice
purposes.
F551)andaflatsurface.Therearedifferentdeformationsofthe
3.1.14 test load, n—the force applied to a tire through the tire footprint on curved versus flat surfaces resulting in
rim; it is normal to the metal loading plate onto which the tire different footprint mechanics, stress/strain cycles, and signifi-
is loaded. F538 cantly different internal operating temperatures for the two
F2869 − 10
types of contact surface. Since tire internal temperatures are running on a flat surface, that is, the targeted operating
key parameters influencing tire endurance or operating char- difference in temperature between the roadwheel and highway
acteristics under typical use conditions, it is important to be condition. By first identifying the desired “delta
able to calculate internal temperature differentials between temperature(s),” the user will be able to identify (via the
curvedandflatsurfacesforarangeofloads,inflationpressures profilers) roadwheel test conditions to achieve the temperature
and rotational velocities (speeds). “delta(s).” The equivalency determination is based upon a
“delta” in rotational speed (km/h), % load, and/or % inflation
5.2 Data from lab and road tire temperature measurement
from the known highway operating conditions within the
trials were combined, statistically analyzed, and tire tempera-
2 limitations specified in Section 6.
ture prediction models derived.
7.1.2 The converse also applies for equivalent highway test
5.2.1 The fit of the models to the data is shown as the
2 conditions that can be identified from specified roadwheel test
coefficient of determination, R , for the critical belt edge:
conditions by use of the curved-to-flat (CTF) prediction
R = 0.90
profilers.
Two Standard Deviations (2-sigma) = 3.2°C
(that is, 95 % of the variation from the means 7.2 When using either the ‘FTC (or CTF) Delta DegC’
is within 63.2°C) prediction profilers, three variables are available for interactive
5.2.2 These prediction models were used to develop the modification:
prediction profilers outlined in Section 7 and Annex A1.
Delta 1.7 m Dia RW KPH The change in tire rotational speed
for the roadwheel relative to the
6. Limitations highway speed in km/h.
1.7 m Dia RW % Flat Surface The percent change in roadwheel
6.1 The procedures as given are valid for radial pneumatic
Inflation tire inflation relative to the
highway tire inflation.
LT tires up through load range E for the following ranges of
1.7 m Dia RW % Flat Surface The percent change in roadwheel
test speed, tire inflation pressure and test load, for flat test
Load tire load relative to the
surfaces and a 1.707-m diameter roadwheels:
highway tire load.
6.1.1 Tire test speed in the range of 80 to 137 km/h (flat and
7.2.1 These variables appear along the x-axis of the predic-
curved surface).
tion profiler and can be changed by clicking and dragging.
6.1.2 Tire test inflation pressure in the range of 50 to 110 %
Effects of changing these variables can be viewed as tempera-
of the inflation pressure associated with the maximum load
ture changes in the belt edge region identified on the y-axis as:
capacity of the tire, for example, sidewall stamped.
6.1.3 Tire test load in the range of 41 to 143 % of the
“LT BE Flat Surface to 1.7 m Dia RW Delta DegC”
maximum load capacity of the tire, for example, sidewall-
stamped maximum rated load.
7.3 The curved-to-flat (CTF) prediction y-axis is labeled
“LT BE 1.7 m Dia RW to Flat Surface Delta DegC” while the
6.2 The procedures described in Section 7 determine
x-axis are labeled from the perspective of identifying the
equivalent operating conditions between a flat surface and a
required changes from roadwheel conditions to flat conditions
1.707-m diameter roadwheel by using empirical models to
in order to achieve the targeted severity levels on the flat
match tire internal belt edge temperatures. These empirical
surface.
models are derived from a wide variety of tires tested within
the above ranges and can be used to interpolate at any
7.4 See Annex A1 for examples of prediction profilers
conditions within the constraints listed above. It is not recom-
outputs.
mended that the procedures be used for extrapolation beyond
7.5 Flat-to-Curved (FTC) Prediction Profiler – Macro But-
the constraints listed above.
ton (available on electronic copy or ASTM F09 site):
http://www.astm.org/F2869_flat_to_curved.html
7. Procedure
7.6 Curved-to-Flat Surface (CTF) Prediction Profiler –
7.1 Equivalent Test Severity Prediction Profilers:
Macro Button (available on electronic copy or ASTM F09
7.1.1 The flat-to-curved (FTC) prediction profilers are SAS
site):
JMP interactive displays based on algorithms developed from
http://www.astm.org/F2869_curved_to_flat.html
laboratory and highway tire temperature measurements. They
provide 1.707-m diamete
...