ASTM F724-94a(2010)e1
(Test Method)Standard Test Method for Outdoor Evaluation of Tire Sidewall Component Cracking Resistance
Standard Test Method for Outdoor Evaluation of Tire Sidewall Component Cracking Resistance
SIGNIFICANCE AND USE
Test Methods D518, D1149, D1171, and D3395 can be used to evaluate different aspects of fatigue and weather cracking resistance of sidewall component materials in the form of test specimens. The present method applies to complete tires that are subjected to actual weather exposure conditions. The present method is satisfactory for research and development purposes but is not applicable to regulatory statutes or purchase specifications until standard classifications of state of cracking, similar to those in Test Method D1171, can be established.
SCOPE
1.1 This test method covers procedures for evaluating passenger car tires for sidewall component integrity and cracking resistance, using an outdoor roadwheel.
1.2 This test method evaluates the resistance of tire sidewalls to dynamic weathering, atmospheric ozone cracking, fatigue cracking, or openings of splices within, or of junctures between, sidewall components and cracking at molded sidewall elements.
1.3 This test method is useful for evaluating tire black sidewalls, white, or other colored, sidewalls, and coverstrips.
1.4 This test method is limited to comparative performance testing between a “control” sidewall component or assembly and one or more experimental alternatives that are built onto the same tire (“multisection”) or onto tires that are identical in all respects other than the sidewall variation.
1.5 This test method is not applicable to evaluation of sidewall resistance to abrasion, as may be experienced in severe cornering or curb scuffing.
1.6 The values stated in SI units are to be regarded as the standard.
1.7 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. For specific precaution statements, see 5.2.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F724 − 94a(Reapproved 2010)
Standard Test Method for
Outdoor Evaluation of Tire Sidewall Component Cracking
Resistance
ThisstandardisissuedunderthefixeddesignationF724;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially corrected 1.3 and Fig. 2 in April 2010.
1. Scope 2. Referenced Documents
1.1 This test method covers procedures for evaluating pas- 2.1 ASTM Standards:
senger car tires for sidewall component integrity and cracking D518 Test Method for Rubber Deterioration—Surface
resistance, using an outdoor roadwheel. Cracking (Withdrawn 2007)
D1149 Test Methods for Rubber Deterioration—Cracking in
1.2 This test method evaluates the resistance of tire side-
an Ozone Controlled Environment
walls to dynamic weathering, atmospheric ozone cracking,
D1171 Test Method for Rubber Deterioration—Surface
fatigue cracking, or openings of splices within, or of junctures
Ozone Cracking Outdoors or Chamber (Triangular Speci-
between, sidewall components and cracking at molded side-
mens)
wall elements.
D3395 Test Methods for Rubber Deterioration—Dynamic
1.3 This test method is useful for evaluating tire black
Ozone Cracking in a Chamber (Withdrawn 2007)
sidewalls, white, or other colored, sidewalls, and coverstrips.
F538 Terminology Relating to the Characteristics and Per-
1.4 This test method is limited to comparative performance formance of Tires
testing between a “control” sidewall component or assembly
3. Terminology
and one or more experimental alternatives that are built onto
3.1 Definitions:
the same tire (“multisection”) or onto tires that are identical in
3.1.1 black sidewall, n—a sidewall on which only black
all respects other than the sidewall variation.
compounds comprise the outer visible surface of a tire. F538
1.5 This test method is not applicable to evaluation of
3.1.2 clinch strip, n—high-modulus or high-hardness com-
sidewall resistance to abrasion, as may be experienced in
pound applied between the carcass and the sidewall in the bead
severe cornering or curb scuffing.
area to reinforce the bead. F538
1.6 The values stated in SI units are to be regarded as the
3.1.3 coverstrip, n—a thin layer of black compound that
standard.
covers the unexposed white sidewall portion of a finished tire.
1.7 This standard does not purport to address all of the
F538
safety concerns, if any, associated with its use. It is the
3.1.4 crazing, n—minute, closely grouped, generally super-
responsibility of the user of this standard to establish appro-
ficial cracks that usually result from light-activated oxidation.
priate safety and health practices and determine the applica-
F538
bility of regulatory limitations prior to use. For specific
3.1.5 flex cracking, v—cracking primarily caused by appli-
precaution statements, see 5.2.
cation of mechanical stress-strain cycling. F538
1 2
This test method is under the jurisdiction of ASTM Committee F09 on Tires For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and is the direct responsibility of Subcommittee F09.30 on Laboratory (Non- contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Vehicular) Testing. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2010. Published February 2011. Originally the ASTM website.
approved in 1981. Last previous edition approved in 2004 as F724 – 94a (2004). The last approved version of this historical standard is referenced on
DOI: 10.1520/F0724-94AR10E01. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F724 − 94a (2010)
3.1.6 juncture, n—the interface between two different tire 5.1.2 Satellite stations for loading several test tires against
components or different compounds within the same the road wheel with known constant force.
component. F538 5.1.2.1 Each satellite station can individually unload and
withdraw the tire from contact with the road wheel in the event
3.1.7 juncture cracking, n—acrackwithopeningoriginating
of an inflation pressure loss or other potentially catastrophic
at a juncture between two components. F538
occurrence.
3.1.8 juncture opening, n—a separation developing in a
5.1.2.2 The tire-loading system may be done by any system
juncture. F538
that provides a constant force to maintain the desired tire
3.1.9 rim strip, n—a layer of compound, with or without
deflection throughout the test.
fabric reinforcement, that is applied at the bead to protect the
5.1.3 Adrive motor that can drive the road wheel(s), within
carcasspliesagainstdamagefrommountingtoolsandfromrim
61 % of a set test speed for extended periods of time. A
chafing during service. F538
commonly used speed is 48 km/h (30 mph).
5.1.4 System for determining accumulated cycles of rota-
3.1.10 sidewall, n—of a tire, that portion of a tire between
the tread and the bead. F538 tion of each test tire.
3.1.11 sidewall component, n—an individual part of the
5.2 Safety Precautions:
sidewall construction, either a separate compound or a sepa- 5.2.1 The apparatus shall be surrounded by a suitable
rately assembled piece. F538
enclosure to trap tire fragments in the event of a catastrophic
failure during the test.
3.1.12 sidewall rubber, n—the exterior rubber layer of a tire
5.2.2 The controls for the apparatus shall be situated outside
that extends over the sidewall part of the carcass. F538
the enclosure.
3.1.13 splice, n—the joint formed either by overlapping or
butting the ends of a given tire component in the course of
6. Sampling
assembling the tire. F538
6.1 Asampling plan is not applicable since this test method
3.1.14 splice crack, n—a crack originating at a splice. F538
is intended for research and development testing only. Test
3.1.15 splice opening, n—a parting of a splice along the
specimens (see Section 7) shall be tested simultaneously with
interface of the assembled ends of a given component. F538
a control specimen for direct comparison of relative perfor-
3.1.16 veneer, n—a thin layer of rubber covering the surface
mance.
of the tire sidewall. F538
7. Test Specimens
3.1.17 weather cracking, n—distinct surface cracks induced
by action of ozone in those areas of sidewall that are under
7.1 A test specimen shall be a given assembly of sidewall
tension; the cracks usually form perpendicularly to the direc-
components, specific as to component formulations, assembly
tion of stress.
cross-section geometry, and preparation procedure. The test
3.1.18 white sidewall, n—a sidewall that contains a white specimen may cover the entire sidewall circumference of the
test tire and be compared with a control tire or it may cover a
(or light-colored) compound as a part of the total sidewall.
F538 section of the sidewall and be compared with a control section
and other test specimen sections built onto the same (multi-
4. Significance and Use section) tire.
7.2 Atest specimen section shall cover ⁄4 of the circumfer-
4.1 Test Methods D518, D1149, D1171, and D3395 can be
used to evaluate different aspects of fatigue and weather ence of the tire sidewall.
cracking resistance of sidewall component materials in the
7.3 In multisection tire tests, only specimens on the same
form of test specimens. The present method applies to com-
side of the tire shall be compared directly.
plete tires that are subjected to actual weather exposure
conditions. The present method is satisfactory for research and
8. Selection and Preparation of Test Tires
development purposes but is not applicable to regulatory
8.1 All test tires shall be approximately the same age and
statutes or purchase specifications until standard classifications
subjected to the same pretest conditions, particularly as related
ofstateofcracking,similartothoseinTestMethodD1171,can
to heat and ultraviolet exposure.
be established.
8.2 Multisection test tires shall have been prepared with the
5. Apparatus test components (for example, varied compounds) having the
same cross-sectional profile and dimensions, so as to avoid
5.1 Outdoor Roadwheel—An apparatus situated outdoors
extraneous mechanical stress variability between the
and consisting of:
components, unless the profile variation is a test variable.
5.1.1 One or more smooth steel road wheels of specified
diameter. The road wheel(s) shall be wide enough to extend 8.3 The test component surfaces of tires shall be washed
beyond the test tire foot print width. The road wheel diameter with water to remove any temporary protective coating but
shall be no less than 610 mm (24 in.). Smaller diameter wheels shall not be subjected to solvent or other surface treatment (in
may produce excessive flexing and premature extraneous tire the process of mounting, etc.) that may affect performance
failure. unless this is a part of the experimental study.
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F724 − 94a (2010)
9. Procedure 9.7 Test duration is discretionary but generally need not
exceed 64 000 km (40 000 miles), which requires 56 to 60
9.1 Mount a test tire on a rim contour approved by the Tire
4 days.
and Rim Association for its particular size. For tire-to-tire
9.8 Data sheet formats for recording test conditions, peri-
comparative tests, rims shall be of the same width.
odic inspection data, and observations appear in F
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