ISO 5273:2025

International
Standard
ISO 5273
First edition
Passenger car tyres — Preparation
2025-01
method for an artificially worn state
for wet grip testing
Pneus pour voitures particulières — Méthode de préparation
d'une usure artificielle pour les essais d'adhérence sur revêtement
mouillé
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Equipment and instrumentation . 3
5 Preparation for buffing . . 3
6 Buffing conditions . 6
7 Buffing procedure . 6
8 Buffing qualification determination rules . 7
8.1 General .7
8.2 Requirements .7
Annex A (informative) Example report of an artificially worn state for a passenger car tyre . 9
Annex B (informative) Examples of unqualified cutter, grinding, and buffing results .11
Bibliography .12

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves, Subcommittee SC 3,
Passenger car tyres and rims.
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International Standard ISO 5273:2025(en)
Passenger car tyres — Preparation method for an artificially
worn state for wet grip testing
1 Scope
This document specifies the preparation of artificially worn tyres by tread rubber removal (e.g. cutter,
buffing, grinding, etc.) for subsequent wet grip performance tests. This document applies to new passenger
car tyres.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 4000-1, Passenger car tyres and rims — Part 1: Tyres (metric series)
ISO 4223-1, Definitions of some terms used in the tyre industry — Part 1: Pneumatic tyres
ISO 21920-2, Geometrical product specifications (GPS) — Surface texture: Profile — Part 2: Terms, definitions
and surface texture parameters
ASTM F421, Standard Test Method for Measuring Groove and Void Depth in Passenger Car Tires
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4000-1, ISO 4223-1, ISO 21920-2,
ASTM F421, and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
tyre contour
geometrical shape of tyre shoulder and tread
Note 1 to entry: An example of tyre contour is shown in Figure 1.
Figure 1 — Tyre contour
Note 2 to entry: Tyre contour should be obtained, e.g. by scan method.

3.2
groove
void volume between two adjacent ribs or blocks in the tread pattern
3.3
groove depth
vertical distance between the lowest point at bottom of tread pattern and tangent line of tyre surface
3.4
centre line
line dividing the overall width of the tyre in two equal parts
3.5
mould parting line
border circumference in which mould tread pattern segments connects with mould sidewall plates
Note 1 to entry: If no mould parting line is visible on the tyre, a virtual mould parting line shall be considered as the
circumferential line in the equivalent position at the end of the shoulder grooves.
3.6
reference tread width
C
tyre tread width as calculated by:
1,001
Ca=−()1,,075 0 005 rs
where:
ar is the nominal aspect ratio;
s is the nominal section width on measuring rim.
Note 1 to entry: Reference tread width is as shown in Figure 2.
Figure 2 — Reference tread width (C)
3.7
central part of the tread
CP
75 % of reference tread width in the central tread, symmetrically measured from the centre line

3.8
tread pattern limit points
points in the tread which are 15 mm away from the mould parting line on the tread shoulder profile towards
centre line
Note 1 to entry: The left limit point is marked with L , and the right is marked with L (see Figure 4).
i e
3.9
shoulder control area of the tread
shoulder area between the edge of the central part of the tread and the tread pattern limit points
3.10
target groove depth
target vertical distance between the lowest point at bottom of tread pattern and tangent line of tread surface
after artificially prepared
3.11
groove depth after buffing
actual vertical distance between the lowest point at bottom of tread pattern and tangent line of tread surface
after artificially prepared
3.12
groove average depth
average of all tyre groove
...