1、Designation: F 1426 94 (Reapproved 2003)Standard Practice forIdentifying Tire Tread Surface Irregular Wear PatternsResulting from Tire Use1This standard is issued under the fixed designation F 1426; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONOne of the main performance characteristics of tires is the treadlife, defined as the num
3、ber ofkilometres or miles to wear out, that is, to the disappearance of the tread pattern. Before reaching thecondition called“ wear out,” intermediate conditions of treadwear are frequently encountered, both intire testing and in normal tire use, that are characterized by complex topological tread
4、pattern featuresusually called “irregular tire wear.” When irregular wear is present, certain other tire performancefeatures, such as noise and handling, may fall below acceptable norms. Therefore, it is important intire development testing and the assessment of tire use performance to be able to de
5、scribe accuratelythe condition of the worn surface of tires.Over the years, different descriptive names have been given to these worn tread pattern features. Astandardized nomenclature system is needed to be able to identify the features that are present anddescribe the intensity or magnitude of the
6、se features. This practice is intended to give sufficientinstructions to permit an evaluation of irregular treadwear. To describe adequately the features of thesetread patterns, it is necessary to develop a special logical progressive sequence of definitions ordescriptions.1. Scope1.1 This practice
7、provides the instructions and nomenclatureto evaluate the wear features of the tread pattern on a tire forsome intermediate state short of total wear out.1.2 A tire may be characterized by certain worn treadpattern conditions that are collectively referred to as “irregularwear” features. Definitions
8、 for these features are given in aspecial logical and conceptual sequence. First, basic treadpattern definitions are given. Then, additional tread patterndefinitions directly related to the basic tread pattern definitionsare given. Understanding these secondary definitions requiresthe knowledge of t
9、he basic definitions.1.3 Based on the terms of this developed system of treadpattern definitions or descriptions, a set of treadwear descrip-tions is presented that encompasses both regular wear andirregular wear features.1.4 This hierarchical arrangement produces the accurate andconcise definitions
10、 needed to evaluate the complex irregularwear conditions of tires.1.5 See Fig. 1 for tread pattern features or characteristics.See Fig. 2 and Fig. 3 for typical illustrations of regular oruniform and irregular treadwear features.2. Significance and Use2.1 This practice fulfills the need for a standa
11、rdized systemfor identifying and describing the tread pattern features of tiresthat are characteristic of intermediate states of treadwear shortof total wear out. This descriptive capability is especiallyimportant in testing programs devoted to the development ofimproved performance tires. It is als
12、o important in assessingand evaluating tires after periods of typical tire usage.3. Elementary Features of Tire Tread Patterns3.1 All tires contain an annular volume of rubber, theoutside surface of which comes into contact with the pavementas a loaded tire rotates in vehicle use. This is defined be
13、low asa tread band. If surface voids are introduced into this treadband, the usual configuration of these voids produces ageometric pattern of remaining surface projections or elements,that is, regions of the tread band that contact the pavement,collectively called a tread pattern.1This practice is
14、under the jurisdiction of ASTM Committee F09 on Tires and isthe direct responsibility of Subcommittee F09.94 on Terminology.Current edition approved July 15, 1994. Published September 1994. Originallyapproved in 1993. Last previous edition approved in 1999 as F 1426 94 (1999).1Copyright ASTM Interna
15、tional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Tire Inspection4.1 The tread pattern of tires for inspection and evaluationshould be clean and free of debris. Tires may be inspectedunmounted (on a rim), but it is recommended that tires bemounted and inf
16、lated to normal recommended inflation pres-sure.4.2 Position the tire to be evaluated in a vertical orientation(that is, the plane of the tire is vertical) on a fixture that permitsrotating the tire. Provide sufficient illumination for viewing thetread pattern. A movable secondary source of illumina
17、tion witha light path tangential to the tread surface is often useful forviewing subtle wear features.4.2.1 Observe the entire tread pattern of the tire and recordthe treadwear features of the tire according to the wearnomenclature system as given in Sections 7 and 8.4.3 There are two options for re
18、cording the observed treadpattern features:4.3.1 Option 1Record all of the features observed on thetread pattern, or4.3.2 Option 2Record all of the features observed on thetread pattern with a qualitative indication of the magnitude orintensity of each feature. Recommended qualifiers are: slight,mod
19、erate, or severe.5. Basic Definitions of General Tread Pattern Features5.1 tread band, n an annular volume of rubber thatencompasses the outer pavement contacting periphery of a tire;the width is normally much greater than the thickness, and bothof these dimensions vary with tire size.5.2 void, na v
20、olume (in the tread band) defined by thelack of rubber; the depth dimension of this volume may varyfrom point to point in (on) the tread band.5.3 groove, na void that is relatively narrow compared toits length.5.4 projection, n a pavement contacting area of the treadband bounded by void.6. Definitio
21、ns of Subclassifications of Basic Tread PatternFeatures6.1 Grooves are major features that may be characterized asfollows:6.1.1 longitudinal groove, nan endless groove that has itsmajor (long) dimension substantially parallel to the tire cir-cumferential centerline; the walls of the groove may not b
22、eFIG. 1 Tread Pattern CharacteristicsFIG. 2 Uniform or Regular WearF 1426 94 (2003)2perfectly parallel planes, but may have short alternating sec-tions of the wall at angles to the tire circumferential centerline.6.1.2 lateral groove, na groove that has its long dimen-sion oriented at a direction no
23、nparallel to the tire circumferen-tial centerline; it most frequently opens into a void at bothends.6.2 Secondary groove-like features are defined as follows:6.2.1 notch, na groove smaller in both width and lengththan a lateral groove that contains one closed end.6.2.2 sipe, na molded or cut rectang
24、ular void that issubstantially narrower than the major grooves or voids.NOTEIn illustrations (a), (e), and (f) the 8light or 8featureless areas indicate high wear rate zones.FIG. 3 Types of Irregular WearF 1426 94 (2003)36.3 Projections are major pavement contacting tread bandregions, defined as fol
25、lows:6.3.1 rib, na continuous circumferential projection.6.3.2 shoulder rib, na rib at or near the outer edge orshoulder of the tread band.6.3.3 center rib, na rib at or near the circumferentialcenterline of the tread band.6.3.4 intermediate rib, none or more rib(s) located be-tween the centerline a
26、nd the shoulder ribs of the tread band.6.3.5 element, nan isolated (totally bounded by void)projection.6.3.6 block, nsynonym for element.6.3.7 row, na rib or a continuous collection of elementsthat lie on a circumferential line parallel to the circumferentialcenterline of the tread band.6.3.8 should
27、er row, na row located at or near the shoulderof the tread band.6.3.9 center row, na row located at or near the circumfer-ential centerline.6.3.10 intermediate row, na row located between thecircumferential centerline and the shoulder ribs/rows of thetread band.7. General Treadwear Definitions7.1 un
28、iform wear, na type of treadwear characterized byequal tread loss both from projection to projection and frompoint to point on a given projection, resulting in a smoothappearance of all parts of the tread pattern.7.2 regular wear, nsynonym for uniform wear.7.3 irregular wear, na type of treadwear ch
29、aracterized bysubstantial variations of tread loss both from projection toprojection and frequently from point to point on a givenprojection.8. Irregular Treadwear Definitions8.1 Descriptions of irregular wear are given in three catego-ries: (1) intraprojection wear features, (2) interprojection wea
30、rfeatures, and (3) independent (of projection) wear features.8.2 Intraprojection (Irregular) Wear Features:8.2.1 intraprojection wear, na type of irregular wearcharacterized by a different wear rate at two or more locationswithin a given projection.8.2.2 heel-toe wear, na type of irregular wear char
31、acter-ized by different wear rates at the leading and trailing edges ofa projection (element).8.2.3 feathering, na type of element irregular wear char-acterized by thin strips of rubber extending from the edge ofthe element.8.3 Interprojection (Irregular) Wear Features:8.3.1 interprojection wear, na
32、 type of irregular treadwearcharacterized by different wear rates on one or more adjacentprojections (either transverse or circumferential orientation);this results in a step-off in tread depth between the adjacentprojections.8.3.2 shoulder wear, na type of irregular wear character-ized by an increa
33、sed wear rate in the outer edge of the shoulderrib or row compared to the inner shoulder edge.8.3.3 row/rib wear, na type of irregular wear character-ized by a greater wear rate in one or more rows/ribs; theincreased wear rate may occur at one or more circumferentiallocations in (on) a given row/rib
34、 and is independent of (that is,occurs across) individual projections resulting in a step-off intread depth between adjacent rows/ribs.8.3.4 step wear, na synonym for row/rib wear.8.3.5 center wear, n a type of irregular wear characterizedby a wear rate continuously increasing from shoulder to cente
35、rof the tread band.8.4 Independent (Irregular) Wear Features:8.4.1 diagonal wear, na type of irregular wear character-ized by an increased wear rate region or band orientedtransversely (from shoulder to shoulder) at some non-90 anglewith respect to the circumferential centerline of the tread band.8.
36、4.2 cupping, na type of irregular wear characterized bya variation in wear rate that may be periodic (essentiallycycloidally shaped) around the tread band circumference in oneor more rows; the variation of loss is essentially independent ofindividual projections if the pattern contains these project
37、ions.8.4.3 chip and tear, na special type of irregular wearcharacterized by a rough tread surface which may containcracks, abrasion pits, or surface ruptures.9. Keywords9.1 irregular wear; tire; tread pattern; tread surface; tread-wear; wear patternASTM International takes no position respecting the
38、 validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is
39、 subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Hea
40、dquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This st
41、andard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 1426 94 (2003)4
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