1、Designation: F1016 07 (Reapproved 2013)1Standard Practice forLinear Tire Treadwear Data Analysis1This standard is issued under the fixed designation F1016; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorial corrections made throughout in June 2013.1. Scope1.1 This practice describes the elementary linear regressionanalysis of basic tre
3、adwear data as obtained according to TestMethod F421 and Test Method F762.1.2 The basic treadwear data are obtained as groove depthloss measurements by procedures described in Test MethodF421 after a series of test cycles (test distances under specifiedconditions) according to Test Method F762.1.3 A
4、 linear regression analysis is performed for the rela-tionship between average tire tread depth and the test distancetraveled by the test vehicle, on which the test tires are mounted.From this analysis a rate of wear is determined: groove depthloss per unit distance.1.4 Linear treadwear is defined a
5、s an essentially constantrate of wear, after break-in, which results in a linear regressioncoefficient of determination, R2, equal to or greater than 0.95when obtained for a data set where the number of measurementintervals, n, is at least 3. Each measurement interval representsa specific test dista
6、nce.1.5 This practice is not applicable to the prediction oftreadlife for tires that exhibit non-linear or irregular treadwear.1.6 Evaluation parameters are given for both SI and inch-pound units; either may be used. The evaluation parameters asdefined are ones typically used in the tire testing ind
7、ustry andno special claim is made for superiority of these parametersand terms over other terms and parameters that may bedeveloped.2. Referenced Documents2.1 ASTM Standards:2F421 Test Method for Measuring Groove and Void Depth inPassenger Car TiresF538 Terminology Relating to the Characteristics an
8、d Per-formance of TiresF762 Test Method for Determining Change in Groove (orVoid) Depth With Distance Traveled for Passenger CarTires3. Terminology3.1 Definitions:3.1.1 average tire tread depth, L,nthe average of all tiregroove (void) depth measurements. F5383.1.2 break-in, L,none or more periods of
9、 initial stan-dardized tire operation during which tire is brought to the statewhich will lead to more consistent test results. F5383.1.3 fastest wearing groove, L,nthe circumferentialgroove with the minimum life expectancy. F5383.1.4 fastest wearing location, L,nthat location whichexhibits the high
10、est percent tread (depth) loss as calculated in6.1.1. F5383.1.5 groove, average depth, L,nthe average of all tiregroove depth measurements in a single groove. F5383.1.6 projected treadlife, L,nthe test distance that givesh as the average tread depth; where h is the height of treadwearindicator above
11、 groove (or void) base. F5383.1.7 test distance, L,ndistance traveled by a vehicleafter tire break-in. F5384. Summary of Practice4.1 This practice provides a calculation procedure for linearregression analysis of treadwear data to be used in the tireindustry for assessing tire treadwear performance.
12、4.2 No specific mathematical formulas are given for thecustomary least-squares calculations used for linear regressionparameter evaluation since these calculation algorithms arereadily available with electronic hand calculators or statisticalsoftware for personal computers, or both. Terms are define
13、d forslope, intercept, and coefficient of determination.1This practice is under the jurisdiction of ASTM Committee F09 on Tires and isthe direct responsibility of Subcommittee F09.30 on Laboratory (Non-Vehicular)Testing.Current edition approved June 1, 2013. Published September 2013. Originallyappro
14、ved in 1986. Last previous edition approved in 2007 as F1016 07. DOI:10.1520/F1016-07R13E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document S
15、ummary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 The purpose of this practice is to standardize themeaning and derivation of some terms and indexes that arecommonly used to char
16、acterize treadwear.5.1.1 There is no intent to recommend either of the twotreadwear performance indexes: distance per unit loss of treaddepth or loss of tread depth per distance unit.6. Calculation6.1 Use the following calculations and terms to reporttreadwear:6.1.1 The percentage tread (depth) loss
17、 (PTL) expresses theloss of tread depth as a percent of the initial tread depth (to thetread-depth indicators), as follows:PTL 5FXi2 XkXi2 hG3100 (1)where:Xi= average tread depth after a break-in (see 3.1.1 or 3.1.2),Xk= average tread depth at a given observation or testdistance (see 3.1.1 or 3.1.7)
18、, andh = height of treadwear indicator above groove (or void)base.6.1.2 The percentage tread (depth) remaining (PTR) ex-presses the remaining tread depth as a percent of the initialtread depth (to the tread-depth indicators), as follows:PTR 5 100 2 PTL (2)6.1.3 The rate of wear, RW, is obtained as t
19、he slope, b(either for SI or inch-pound units), of the regression line ofaverage tire tread depth (y-variable) versus the test distance(x-variable). See 3.1.1 and 3.1.7 for definitions. The interceptof the regression line on the tread depth axis is defined by theterm a.6.1.3.1 Specifically, rate of
20、wear RW is defined as follows:RW in mm/1000 km! 5 1000 3 bM! (3)where b(M) = slope of regression line (metric units), mm/kmandRW in mils/1000 miles! 5 1000 3 bE! (4)where b(E) = slope of regression line (English units), milsper mile (1 mil = 0.001 in.).NOTE 1For the rate of wear in this practice, th
21、e selected SI unit fortest distance is 1000 km. The selected unit for tread depth is themillimetre. For strict SI use the metre (m) should be used. If this is used,then tread depths should be expressed in terms of nanometres (mm) (109m) to produce roughly equivalent magnitude numbers to the mil/1000
22、miles inch-pound units usage. The use of the nanometres per metreexpression presents difficulties in conceptualization of treadwear rates thatis, it is easier to think in terms of millimetres/1000 km than nanometres/metre.6.1.4 The inverse rate of wear (IRW) is the test distancetraveled after break-
23、in per unit loss in tread depth, as given in(Eq 5) in SI units and in (Eq 6) in inch-pound units as follows:IRW1000 km/mm! 51RW mm/1000 km!(5)IRW1000 mi/mil! 51RW mils/1000 mi!(6)where RW = absolute loss in tread depth per unit testdistance after break-in.6.1.5 The wear performance index, a calculat
24、ed value thatrelates the wear performance of a candidate tire to that of acontrol tire tested in the same test, may alternatively becalculated on the basis of either percent loss or tread depth (Eq7) to give TLI, a treadlife index, or on the basis of rate of wear(Eq 8) to give TWI, a treadwear index
25、. The two areequivalent if the initial tread depth of the candidate tire is equalto that of the control tire.TLI 5% loss in control tire% loss in candidate tire3100 (7)TWI 5RW of control tireRW of candidate tire3100 (8)6.1.5.1 The inverse of each of these expressions may also beused.7. Projected Tre
26、adlife Considerations7.1 Projected treadlife is usually calculated for each tire in aset so that tire-to-tire variances, as well as overall means, maybe considered.7.2 If wear rates are linear, a knowledge of the wear ratepermits a prediction of the travel distance to wear-out, that is,to the wear i
27、ndicators. In the inch-pound system of units this isoften called the projected mileage.7.3 Different ribs or blocks on a tread surface often wear atdifferent rates. When this happens the end point for treadwearmay be determined from that at the fastest wearing location.7.4 Types of Projected Treadli
28、fe7.4.1 Uniform Treadwear:7.4.1.1 Projected Tread Life (TL) of tires demonstratinglinear treadwear and uniform tread depths around the circum-ference of the tire (uniform within 10 % of the mean treaddepths for each groove) is calculated in (Eq 9) in kilometersand (Eq 10) in miles:TLkm! 5 1000h mm!
29、2 aRWmm/1000 km!1break-in km! (9)where:h = height of tread wear indicator, mm,a = intercept (on tread depth axis) of the regression linefor regression of loss in mm and test distance in km,andRW = rate of wear, mm/1000 km.TLmi! 5 1000h mils! 2 aRW mils/1000 mi!1break-in mi! (10)where:h = height of t
30、read wear indicator, mils,a = intercept (on tread depth axis) of the regression linefor regression of loss in mils and test distance inmiles, andRW = rate of wear, mils/1000 miles.F1016 07 (2013)127.4.1.2 Alternatively, the depth loss at the fastest wearinglocation or groove may be used instead of t
31、he average tire treaddepth, as defined in 3.1.1, for calculating the rate of wear.Under these conditions RW would refer to the rate of wear ofthe fastest wearing groove or other location and TL wouldrepresent the projected treadlife of the tire on the basis of thisrapid wearing location.7.4.1.3 Norm
32、ally h is 1.59 mm or 63 mils (0.063 in.) forpassenger car tires, and tread depth is the mean distance to thebottom of the groove at locations apart from the treadwearindicators.7.4.2 Non-Uniform TreadwearIf the tread depths are lin-ear with traveled distance but not uniform to within 10 % of themean
33、 tread depths around the circumference of the tire, thetreadlife projection should be made for the fastest wearinglocation. This is accomplished by using the groove depth lossat this location rather than the average tire tread depth.8. Keywords8.1 groove depth; linear; linear tire treadwear; tread d
34、epth;treadwear; wear-outASTM International takes no position respecting the 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 infringe
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37、nown to the ASTM Committee on Standards, at the address shown below.This standard 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).F1016 07 (2013)13
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