ASTM F724-94a(2016)

Standard Test Method for Outdoor Evaluation of Tire Sidewall Component Cracking Resistance

SIGNIFICANCE AND USE
4.1 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

• Status: Historical
• Publication Date: 31-Dec-2015
• ICS: 83.160.10 - Road vehicle tyres
• Technical Committee: F09 - Tires
• Drafting Committee: F09.30 - Laboratory (Non-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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: F724 − 94a (Reapproved 2016)
Standard Test Method for
Outdoor Evaluation of Tire Sidewall Component Cracking
Resistance
This standard is issued under the fixed designation F724; 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 D518 Test Method for Rubber Deterioration—Surface
Cracking (Withdrawn 2007)
1.1 This test method covers procedures for evaluating pas-
D1149 Test Methods for Rubber Deterioration—Cracking in
senger car tires for sidewall component integrity and cracking
an Ozone Controlled Environment
resistance, using an outdoor roadwheel.
D1171 Test Method for Rubber Deterioration—Surface
1.2 This test method evaluates the resistance of tire side-
Ozone Cracking Outdoors (Triangular Specimens)
walls to dynamic weathering, atmospheric ozone cracking,
D3395 Test Methods for Rubber Deterioration—Dynamic
fatigue cracking, or openings of splices within, or of junctures 3
Ozone Cracking in a Chamber (Withdrawn 2007)
between, sidewall components and cracking at molded side-
F538 Terminology Relating to the Characteristics and Per-
wall elements.
formance of Tires
1.3 This test method is useful for evaluating tire black
3. Terminology
sidewalls, white, or other colored, sidewalls, and coverstrips.
3.1 Definitions:
1.4 This test method is limited to comparative performance
3.1.1 black sidewall, n—a sidewall on which only black
testing between a “control” sidewall component or assembly
compounds comprise the outer visible surface of a tire. F538
and one or more experimental alternatives that are built onto
the same tire (“multisection”) or onto tires that are identical in
3.1.2 clinch strip, n—high-modulus or high-hardness com-
all respects other than the sidewall variation. pound applied between the carcass and the sidewall in the bead
area to reinforce the bead. F538
1.5 This test method is not applicable to evaluation of
3.1.3 coverstrip, n—a thin layer of black compound that
sidewall resistance to abrasion, as may be experienced in
severe cornering or curb scuffing. covers the unexposed white sidewall portion of a finished tire.
F538
1.6 The values stated in SI units are to be regarded as the
3.1.4 crazing, n—minute, closely grouped, generally super-
standard.
ficial cracks that usually result from light-activated oxidation.
1.7 This standard does not purport to address all of the
F538
safety concerns, if any, associated with its use. It is the
3.1.5 flex cracking, v—cracking primarily caused by appli-
responsibility of the user of this standard to establish appro-
cation of mechanical stress-strain cycling. F538
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. For specific
3.1.6 juncture, n—the interface between two different tire
precaution statements, see 5.2.
components or different compounds within the same
component. F538
2. Referenced Documents
3.1.7 juncture cracking, n—a crack with opening originating
2.1 ASTM Standards:
at a juncture between two components. F538
3.1.8 juncture opening, n—a separation developing in a
juncture. F538
This test method is under the jurisdiction of ASTM Committee F09 on Tires
3.1.9 rim strip, n—a layer of compound, with or without
and is the direct responsibility of Subcommittee F09.30 on Laboratory (Non-
fabric reinforcement, that is applied at the bead to protect the
Vehicular) Testing.
Current edition approved Jan. 1, 2016. Published February 2016. Originally carcass plies against damage from mounting tools and from rim
ɛ1
approved in 1981. Last previous edition approved in 2010 as F724 – 94a (2010) .
chafing during service. F538
DOI: 10.1520/F0724-94AR16.
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 last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F724 − 94a (2016)
3.1.10 sidewall, n—of a tire, that portion of a tire between 5.1.4 System for determining accumulated cycles of rota-
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 A sampling 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
specimen may cover the entire sidewall circumference of the
3.1.18 white sidewall, n—a sidewall that contains a white
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.
section of the sidewall and be compared with a control section
F538
and other test specimen sections built onto the same (multi-
section) tire.
4. Significance and Use
7.2 A test specimen section shall cover ⁄4 of the circumfer-
4.1 Test Methods D518, D1149, D1171, and D3395 can be
ence of the tire sidewall.
used to evaluate different aspects of fatigue and weather
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
of state of cracking, similar to those in Test Method D1171, can
to heat and ultraviolet exposure.
be established.
8.2 Multisection test tires shall have been prepared with the
test components (for example, varied compounds) having the
5. Apparatus
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
8.3 The test component surfaces of tires shall be washed
diameter. The road wheel(s) shall be wide enough to extend
with water to remove any temporary protective coating but
beyond the test tire foot print width. The road wheel diameter
shall not be subjected to solvent or other surface treatment (in
shall be no less than 610 mm (24 in.). Smaller diameter wheels
the process of mounting, etc.) that may affect performance
may produce excessive flexing and premature extraneous tire
unless this is a part of the experimental study.
failure.
5.1.2 Satellite stations for loading several test tires against
9. Procedure
the road wheel with known constant force.
9.1 Mount a test tire on a rim contour approved by the Tire
5.1.2.1 Each satellite station can individually unload and
and Rim Association for its particular size. For tire-to-tire
withdraw the tire from contact with the road wheel in the event
comparative tests, rims shall be of the same width.
of an inflation pressure loss or other potentially catastrophic
occurrence.
9.2 Mount the tire with the valve at a convenient reference
5.1.2.2 The tire-loading system may be done by any system
point for describing the locations of cracks or other degradation
that provides a constant force to maintain the desired tire
as they occur.
deflection throughout the test.
5.1.3 A drive motor that can drive the road wheel(s), within
61 % of a set test speed for extended periods of time. A 4
Available from the Tire and Rim Association, Inc., Crown Pointe, Suite 150,
commonly used speed is 48 km/h (30 mph). 175 Montrose West Ave., Copley, OH 44321.
F724 − 94a (2016)
9.3 Inflate the tire to the se
...

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.
´1
Designation: F724 − 94a (Reapproved 2010) F724 − 94a (Reapproved 2016)
Standard Test Method for
Outdoor Evaluation of Tire Sidewall Component Cracking
Resistance
This standard is issued under the fixed designation F724; 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.
ε NOTE—Editorially corrected 1.3 and Fig. 2 in April 2010.
1. 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.
2. Referenced Documents
2.1 ASTM Standards:
D518 Test Method for Rubber Deterioration—Surface Cracking (Withdrawn 2007)
D1149 Test Methods for Rubber Deterioration—Cracking in an Ozone Controlled Environment
D1171 Test Method for Rubber Deterioration—Surface Ozone Cracking Outdoors (Triangular Specimens)
D3395 Test Methods for Rubber Deterioration—Dynamic Ozone Cracking in a Chamber (Withdrawn 2007)
F538 Terminology Relating to the Characteristics and Performance of Tires
3. Terminology
3.1 Definitions:
3.1.1 black sidewall, n—a sidewall on which only black compounds comprise the outer visible surface of a tire. F538
3.1.2 clinch strip, n—high-modulus or high-hardness compound applied between the carcass and the sidewall in the bead area
to reinforce the bead. F538
3.1.3 coverstrip, n—a thin layer of black compound that covers the unexposed white sidewall portion of a finished tire. F538
3.1.4 crazing, n—minute, closely grouped, generally superficial cracks that usually result from light-activated oxidation. F538
This test method is under the jurisdiction of ASTM Committee F09 on Tires and is the direct responsibility of Subcommittee F09.30 on Laboratory (Non-Vehicular)
Testing.
Current edition approved April 1, 2010Jan. 1, 2016. Published February 2011February 2016. Originally approved in 1981. Last previous edition approved in 20042010
ɛ1
as F724 – 94a (2004).(2010) . DOI: 10.1520/F0724-94AR10E01.10.1520/F0724-94AR16.
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.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F724 − 94a (2016)
3.1.5 flex cracking, v—cracking primarily caused by application of mechanical stress-strain cycling. F538
3.1.6 juncture, n—the interface between two different tire components or different compounds within the same component.
F538
3.1.7 juncture cracking, n—a crack with opening originating at a juncture between two components. F538
3.1.8 juncture opening, n—a separation developing in a juncture. F538
3.1.9 rim strip, n—a layer of compound, with or without fabric reinforcement, that is applied at the bead to protect the carcass
plies against damage from mounting tools and from rim chafing during service. F538
3.1.10 sidewall, n—of a tire, that portion of a tire between the tread and the bead. F538
3.1.11 sidewall component, n—an individual part of the sidewall construction, either a separate compound or a separately
assembled piece. F538
3.1.12 sidewall rubber, n—the exterior rubber layer of a tire that extends over the sidewall part of the carcass. F538
3.1.13 splice, n—the joint formed either by overlapping or butting the ends of a given tire component in the course of
assembling the tire. F538
3.1.14 splice crack, n—a crack originating at a splice. F538
3.1.15 splice opening, n—a parting of a splice along the interface of the assembled ends of a given component. F538
3.1.16 veneer, n—a thin layer of rubber covering the surface of the tire sidewall. F538
3.1.17 weather cracking, n—distinct surface cracks induced by action of ozone in those areas of sidewall that are under tension;
the cracks usually form perpendicularly to the direction of stress.
3.1.18 white sidewall, n—a sidewall that contains a white (or light-colored) compound as a part of the total sidewall. F538
4. Significance and Use
4.1 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.
5. Apparatus
5.1 Outdoor Roadwheel—An apparatus situated outdoors and consisting of:
5.1.1 One or more smooth steel road wheels of specified diameter. The road wheel(s) shall be wide enough to extend beyond
the test tire foot print width. The road wheel diameter shall be no less than 610 mm (24 in.). Smaller diameter wheels may produce
excessive flexing and premature extraneous tire failure.
5.1.2 Satellite stations for loading several test tires against the road wheel with known constant force.
5.1.2.1 Each satellite station can individually unload and withdraw the tire from contact with the road wheel in the event of an
inflation pressure loss or other potentially catastrophic occurrence.
5.1.2.2 The tire-loading system may be done by any system that provides a constant force to maintain the desired tire deflection
throughout the test.
5.1.3 A drive motor that can drive the road wheel(s), within 61 % of a set test speed for extended periods of time. A commonly
used speed is 48 km/h (30 mph).
5.1.4 System for determining accumulated cycles of rotation of each test tire.
5.2 Safety Precautions:
5.2.1 The apparatus shall be surrounded by a suitable enclosure to trap tire fragments in the event of a catastrophic failure during
the test.
5.2.2 The controls for the apparatus shall be situated outside the enclosure.
6. Sampling
6.1 A sampling plan is not applicable since this test method is intended for research and development testing only. Test
specimens (see Section 7) shall be tested simultaneously with a control specimen for direct comparison of relative performance.
7. Test Specimens
7.1 A test specimen shall be a given assembly of sidewall components, specific as to component formulations, assembly
cross-section geometry, and preparation procedure. The test specimen may cover the entire sidewall circumference of the test tire
and be compared with a control tire or it may cover a section of the sidewall and be compared with a control section and other
test specimen sections built onto the same (multisection) tire.
F724 − 94a (2016)
7.2 A test specimen section shall cover ⁄4 of the circumference of the tire sidewall.
7.3 In multisection tire tests, only specimens on the same side of the tire shall be compared directly.
8. Selection and Preparation of Test Tires
8.1 All test tires shall be approximately the same age and subjected to the same pretest conditions, particularly as related to heat
and ultraviolet exposure.
8.2 Multisection test tires shall have been prepared with the test components (for example, varied compounds) having the same
cross-sectional profile and dimensions, so as to avoid extraneous mechanical stress variability between the components, unless the
profile variation is a test variable.
8.3 The test component surfaces of tires shall be washed with water to remove any temporary protective coating but shall not
be subjected to solvent or other surface treatment (in the process of mounting, etc.) that may affect performance unless this is a
part of the experimental study.
9. Procedure
9.1 Mount a test tire on a rim contour approved by the Tire and Rim Association for its particular size. For tire-to-tire
comparative tests, rims shall be of the same width.
9.2 Mount the tire with the valve at a convenient reference point for describing the locations of crack
...