ASTM F1426-11

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Designation: F1426 − 11
Standard Practice for
Identifying Tire Tread Surface Irregular Wear Patterns
1
Resulting from Tire Use
This standard is issued under the fixed designation F1426; 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.
INTRODUCTION
One of the main performance characteristics of tires is the treadlife, defined as the number of
kilometres or miles to wear-out, or where the condition of the tread pattern requires the removal of the
tire. Before reaching the condition called “wear-out,” intermediate conditions of treadwear are
frequently encountered, both in tire testing and in normal tire use, that are characterized by complex
topological tread pattern features usually called “irregular wear.” When irregular wear is present,
certain other tire performance features, such as noise and handling, may fall below acceptable norms.
Therefore, it is important in tire development testing and the assessment of tire use performance to be
able to describe accurately the condition of the worn surface of tires.
Over the years, different descriptive names have been given to these worn tread pattern features.A
standardized nomenclature system is needed to be able to identify the features that are present and
describe the intensity or magnitude of these features. This practice is intended to give sufficient
instructions to permit an evaluation of irregular wear. To describe adequately the features of these
tread patterns, it is necessary to develop a special logical progressive sequence of definitions or
descriptions.
1. Scope 1.5 See Fig. 1 for tread pattern features or characteristics.
See Fig. 2 and Fig. 3 for typical illustrations of regular or
1.1 Thispracticeprovidestheinstructionsandnomenclature
uniform and irregular treadwear features.
to evaluate the wear features of the tread pattern on a tire for
some intermediate state short of total wear out.
2. Significance and Use
1.2 A tire may be characterized by certain worn tread
2.1 This practice fulfills the need for a standardized system
pattern conditions that are collectively referred to as “irregular
for identifying and describing the tread pattern features of tires
wear” features. Definitions for these features are given in a
that are characteristic of intermediate states of treadwear short
special logical and conceptual sequence. First, basic tread
of total wear out. This descriptive capability is especially
pattern definitions are given. Then, additional tread pattern
important in testing programs devoted to the development of
definitions directly related to the basic tread pattern definitions
improved performance tires. It is also important in assessing
are given. Understanding these secondary definitions requires
and evaluating tires after periods of typical tire usage.
the knowledge of the basic definitions.
3. Elementary Features of Tire Tread Patterns
1.3 Based on the terms of this developed system of tread
pattern definitions or descriptions, a set of treadwear descrip- 3.1 All tires contain an annular volume of rubber, the
outside surface of which comes into contact with the pavement
tions is presented that encompasses both regular wear and
irregular wear features. as a loaded tire rotates in vehicle use. This is defined below as
a tread band. If surface voids are introduced into this tread
1.4 This hierarchical arrangement produces the accurate and
band, the usual configuration of these voids produces a
concise definitions needed to evaluate the complex irregular
geometricpatternofremainingsurfaceprojectionsorelements,
wear conditions of tires.
that is, regions of the tread band that contact the pavement,
collectively called a tread pattern.
1
This practice is under the jurisdiction ofASTM Committee F09 on Tires and is
the direct responsibility of Subcommittee F09.94 on Terminology. 4. Tire Inspection
Current edition approved Nov. 1, 2011. Published November 2011. Originally
4.1 The tread pattern of tires for inspection and evaluation
approved in 1993. Last previous edition approved in 2003 as F1426 – 94 (2003).
DOI: 10.1520/F1426-11. should be clean and free of debris. Tires may be inspected
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F1426 − 11
FIG. 1 Tread Pattern Characteristics
4.3.2 Option 2—Record all of the features observed on the
tread pattern with a qualitative indication of the magnitude or
intensity of each feature. Recommended qualifiers are: slight,
moderate, or severe.
5. Basic Definitions of General Trea
...