1、Designation: F1426 11Standard Practice forIdentifying Tire Tread Surface Irregular Wear PatternsResulting from Tire Use1This standard is issued under the fixed designation F1426; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONOne of the main performance characteristics of tires is the treadlife, defined as the number ofkilometres or m
3、iles to wear-out, or where the condition of the tread pattern requires the removal of thetire. Before reaching the condition called “wear-out,” intermediate conditions of treadwear arefrequently encountered, both in tire testing and in normal tire use, that are characterized by complextopological tr
4、ead 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 beable to des
5、cribe accurately the 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 wear. 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 provi
7、des 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 for
8、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 the ba
9、sic 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 need
10、ed 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 standardize
11、d 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 also imp
12、ortant 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 below a
13、sa 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,1This practice is under the jurisdiction of ASTM Committee F09 on Tires and isthe direct responsibility of Subcommittee
14、F09.94 on Terminology.Current edition approved Nov. 1, 2011. Published November 2011. Originallyapproved in 1993. Last previous edition approved in 2003 as F1426 94 (2003).DOI: 10.1520/F1426-11.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unite
15、d States.that is, regions of the tread band that contact the pavement,collectively called a tread pattern.4. Tire Inspection4.1 The tread pattern of tires for inspection and evaluationshould be clean and free of debris. Tires may be inspectedunmounted (off a rim), but it is recommended that tires be
16、mounted and inflated 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 sou
17、rce of illumination 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
18、 options for recording 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
19、are: slight,moderate, 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
20、.5.2 void, na volume (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 vo
21、id.6. Definitions of Subclassifications of Basic Tread PatternFeatures6.1 Grooves are major features that may be characterized asfollows:FIG. 1 Tread Pattern CharacteristicsFIG. 2 Uniform or Regular WearF1426 1126.1.1 longitudinal groove, nan endless groove that has itsmajor (long) dimension substan
22、tially parallel to the tire cir-cumferential centerline; the walls of the groove may not beperfectly 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 direc
23、tion nonparallel 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:NOTEIn illustrations (a), (e), and (f) the 8light or 8featureless areas indicate high wear rate zones.FIG. 3 Types of Irregular WearF14
24、26 1136.2.1 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 rectangular void that issubstantially narrower than the major grooves or voids.6.3 Projections are major pavement contacting tread bandregions, defined as foll
25、ows: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 an
26、d 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 shoulde
27、r 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 uni
28、form 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 cha
29、racterized 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 wear
30、features, and (3) independent (of projection) wear features.8.2 Intra-projection (Irregular) Wear Features:8.2.1 intra-projection 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 cha
31、racter-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 Inter-projection (Irregular) Wear Features:8.3.1 inter-projection wear,
32、 na 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 inc
33、reased 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/
34、rib 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 ce
35、nterof 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
36、.8.4.2 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 proj
37、ections.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
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