ASTM F1016-93(1997)
(Practice)Standard Practice for Linear Tire Treadwear Data Analysis
Standard Practice for Linear Tire Treadwear Data Analysis
SCOPE
1.1 This practice describes the elementary linear regression analysis of basic treadwear data as obtained according to Test Method F421 and Practice F762.
1.2 The basic treadwear data are obtained as groove depth loss measurements by procedures described in Test Method F421 after a series of test cycles (test distances under specified conditions) according to Practice F762.
1.3 A linear regression analysis is performed for the relationship between average tire tread depth and the test distance traveled by the test vehicle, on which the test tires are mounted. From this analysis a rate of wear is determined: groove depth loss per unit distance.
1.4 Linear treadwear is defined as an essentially constant rate of wear, after break-in, which results in a linear regression coefficient of determination, R2, equal to or greater than 0.95 when obtained for a data set where the number of measurement intervals, n, is at least 3. Each measurement interval represents a specific test distance.
1.5 This practice is not applicable to the prediction of treadlife 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 as defined are ones typically used in the tire testing industry and no special claim is made for superiority of these parameters and terms over other terms and parameters that may be developed.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: F 1016 – 93 (Reapproved 1997)
Standard Practice for
Linear Tire Treadwear Data Analysis
This standard is issued under the fixed designation F 1016; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This practice describes the elementary linear regression 3.1 Definitions:
analysis of basic treadwear data as obtained according to Test 3.1.1 average tire tread depth, [L], n—the average of all tire
Method F 421 and Practice F 762. groove (void) depth measurements.
1.2 The basic treadwear data are obtained as groove depth 3.1.2 break-in, [L], n—one or more periods of initial stan-
loss measurements by procedures described in Test Method dardized tire operation during which tire is brought to the state
F 421 after a series of test cycles (test distances under specified which will lead to more consistent test results.
conditions) according to Practice F 762. 3.1.3 groove, average depth, [L], n—the average of all tire
1.3 A linear regression analysis is performed for the rela- groove depth measurements in a single groove.
tionship between average tire tread depth and the test distance 3.1.4 projected treadlife, [L], n—the test distance that gives
traveled by the test vehicle, on which the test tires are mounted. h as the average tread depth; where h is the height of treadwear
From this analysis a rate of wear is determined: groove depth indicator above groove (or void) base.
loss per unit distance. 3.1.5 test distance, [L], n—distance traveled by a vehicle
1.4 Linear treadwear is defined as an essentially constant after tire break-in.
rate of wear, after break-in, which results in a linear regression
4. Summary of Practice
coefficient of determination, R , equal to or greater than 0.95
4.1 This practice provides a calculation procedure for linear
when obtained for a data set where the number of measurement
intervals, n, is at least 3. Each measurement interval represents regression analysis of treadwear data to be used in the tire
industry for assessing tire treadwear performance.
a specific test distance.
1.5 This practice is not applicable to the prediction of 4.2 No specific mathematical formulas are given for the
customary least-squares calculations used for linear regression
treadlife for tires that exhibit non-linear or irregular treadwear.
1.6 Evaluation parameters are given for both SI and inch- parameter evaluation since these calculation algorithms are
readily available with electronic hand calculators or statistical
pound units; either may be used. The evaluation parameters as
defined are ones typically used in the tire testing industry and software for personal computers, or both. Terms are defined for
slope, intercept, and coefficient of determination.
no special claim is made for superiority of these parameters
and terms over other terms and parameters that may be
5. Significance and Use
developed.
5.1 The purpose of this practice is to standardize the
2. Referenced Documents
meaning and derivation of some terms and indexes that are
2.1 ASTM Standards: commonly used to characterize treadwear.
5.1.1 There is no intent to recommend either of the two
F 421 Test Method for Measuring Groove and Void Depth
in Passenger Car Tires treadwear performance indexes: distance per unit loss of tread
depth or loss of tread depth per distance unit.
F 538 Terminology Relating to the Characteristics and Per-
formance of Tires
6. Calculation
F 762 Practice for Determining Change in Groove (or Void)
6.1 Use the following calculations and terms to report
Depth With Distance Traveled for Passenger Car Tires
treadwear:
6.1.1 The percentage tread (depth) loss (PTL) expresses the
loss of tread depth as a percent of the initial tread depth (to the
tread-depth indicators), as follows:
This practice is under the jurisdiction of ASTM Committee F-9 on Tires and is
¯ ¯
X 2 X
the direct responsibility of Subcommittee F09.30 on Laboratory (Non-Vehicular)
i k
PTL 5 100 (1)
F G
Testing. ¯
X 2 h
i
Current edition approved Feb. 15, 1993. Published May 1993. Originally
published as F 1016 – 86. Last previous edition F 1016 – 86.
where:
Annual Book of ASTM Standards, Vol 09.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
F 1016
¯ 7. Projected Treadlife Considerations
X 5 average tread depth after a break-in (see 3.1.1 or
i
3.1.2),
7.1 Projected treadlife is usually calculated for each tire in a
¯
X 5 average tread depth at a given observation or test
k set so that tire-to-tire variances, as well as overall means, may
distance (see 3.1.1 or 3.1.5), and
be considered.
h 5 height of treadwear indicator above groove (or void)
7.2 If wear rates are linear, a knowledge of the wear rate
base.
permits a prediction of the travel distance to wear-out, that is,
6.1.2 The percentage tread (depth) remaining (PTR) ex-
to the wear indicators. In the inch-pound system of units this is
presses the remaining tread depth as a percent of the initial
often called the projected mileage.
tread depth (to the tread-depth indicators), as follows:
7.3 Different ribs or blocks on a tread surface often wear at
different rates. When this happens the end point for treadwear
PTR 5 100 2 PTL (2)
may be determined from that at the fastest wearing location.
6.1.3 The rate of wear, RW, is ob
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