ISO/FDIS 18106

DRAFT
International
Standard
ISO/DIS 18106
ISO/TC 31
Passenger car, commercial vehicle,
Secretariat: ANSI
truck and bus tyres — Methods for
Voting begins on:
measuring snow grip performance
2024-11-25
— Loaded new tyres
Voting terminates on:
2025-02-17
Pneumatiques pour voitures particulières, véhicules utilitaires,
camions et autobus — Méthodes de mesurage de l´adhérence sur
neige — Pneumatiques neufs en charge
ICS: 83.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
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Reference number
ISO/DIS 18106:2024(en)
DRAFT
ISO/DIS 18106:2024(en)
International
Standard
ISO/DIS 18106
ISO/TC 31
Passenger car, commercial vehicle,
Secretariat: ANSI
truck and bus tyres — Methods for
Voting begins on:
measuring snow grip performance
— Loaded new tyres
Voting terminates on:
Pneumatiques pour voitures particulières, véhicules utilitaires,
camions et autobus — Méthodes de mesurage de l´adhérence sur
neige — Pneumatiques neufs en charge
ICS: 83.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2024
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
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Published in Switzerland Reference number
ISO/DIS 18106:2024(en)
ii
ISO/DIS 18106:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test methods . 3
4.1 Braking on snow method for passenger car tyres .3
4.1.1 General .3
4.1.2 Test course .3
4.1.3 Vehicle .4
4.1.4 Standard reference test tyre.4
4.1.5 Tyres preparation .4
4.1.6 Tyre load .4
4.1.7 Tyre inflation pressure .4
4.1.8 Instrumentation.4
4.1.9 Testing order and sequences .4
4.1.10 Test procedure.5
4.1.11 Data evaluation and presentation of results .6
4.1.12 Snow grip performance comparison between a candidate tyre and a reference
tyre using a control tyre . .7
4.2 Braking on snow method for commercial vehicle tyres .7
4.2.1 General .7
4.2.2 Test course .7
4.2.3 Vehicle .7
4.2.4 Standard reference test tyre.7
4.2.5 Tyres preparation .8
4.2.6 Tyre load .8
4.2.7 Tyre inflation pressure .8
4.2.8 Instrumentation.8
4.2.9 Testing order and sequences .8
4.2.10 Test procedure.9
4.2.11 Data evaluation and presentation of results .9
4.2.12 Snow grip performance comparison between a candidate tyre and a reference
tyre using a control tyre . .9
4.3 Acceleration on snow method for truck and bus tyres .9
4.3.1 General .9
4.3.2 Test course .9
4.3.3 Vehicle .10
4.3.4 Standard reference test tyre.10
4.3.5 Tyres preparation .11
4.3.6 Tyre load .11
4.3.7 Tyre inflation pressure .11
4.3.8 Instrumentation.11
4.3.9 Testing order and sequences . 12
4.3.10 Test procedure. 13
4.3.11 Data evaluation and presentation of results . 13
4.3.12 Snow grip performance comparison between a candidate tyre and a reference
tyre using a control tyre . . 15
Annex A (informative) Example of a possible test report of Snow Grip Index for a passenger car
or commercial vehicle tyre .16
Annex B (informative) Example of a possible test report of Snow Grip Index for a truck and bus
tyre .18

iii
ISO/DIS 18106:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT)
see the following URL: Foreword - Supplementary information.
The committee responsible for this document is ISO/TC 31, Tyres, rims and valves.

iv
DRAFT International Standard ISO/DIS 18106:2024(en)
Passenger car, commercial vehicle, truck and bus tyres —
Methods for measuring snow grip performance — Loaded
new tyres
1 Scope
This International Standard specifies the method for measuring relative snow grip performance index of
a candidate tyre compared to a reference, under loaded conditions for new tyres intended to be used on
passenger car, commercial vehicle, truck and bus vehicles on a snow packed surface.
The methods developed here are meant to reduce the variability of the performance measurement. The use
of the proper reference tyres is necessary to limit the variability of the testing method procedures.
This International Standard applies to all passenger car, commercial vehicle, truck and bus tyres.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 4209-1, Truck and bus tyres and rims (metric series) — Part 1: Tyres
ASTM F1805, Standard Test Method for Single Wheel Driving Traction in a Straight Line on Snow- and Ice-
Covered Surfaces
ASTM E1136, Standard Specification for P195/75R14 Radial Standard Reference Test Tire
ASTM F2870, Standard Specification for 315/70R22.5 154/150L Radial Truck Standard Reference Test Tire
ASTM F2871, Standard Specification for 245/70R19.5 136/134M Radial Truck Standard Reference Test Tire
ASTM F2872, Standard Specification for 225/75R16C 116/114S M+S Radial Light Truck Standard Reference Test Tire
ASTM F2493, Standard Specification for P225/60R16 97S Radial Standard Reference Test Tire
ASTM F3677, Standard Specification for 315/70R22.5 154/150L Radial Truck Standard Reference Test Tire SW
ASTM F3678, Standard Specification for 245/70R19.5 136/134M Radial Truck Standard Reference Test Tire SW
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
passenger car tyre
tyres conforming to ISO 4000-1
3.2
commercial vehicle tyre
tyres conforming to ISO 4209-1 and identified by a load index in single configuration lower or equal to 121
and a speed symbol higher or equal to “N”

ISO/DIS 18106:2024(en)
3.3
truck and bus tyre
tyres conforming to ISO 4209-1 and identified by
a) a load index in single configuration higher or equal to 122, or
b) a load index in single configuration lower or equal to 121 and a speed symbol lower or equal to “M”
3.4
test run
single pass of a loaded tyre over a given test surface
3.5
tyre set
group of two or four same tyres
3.6
candidate tyre
T
test tyre set (3.5) that is part of an evaluation program
3.7
reference tyre
R
special test tyre set (3.5), also known as a Standard Reference Test Tyre (SRTT), that is used as a benchmark
in an evaluation program
Note 1 to entry: In order to minimize their variation, these tyres have carefully controlled design features and for
this reason, they are produced, controlled and stored in accordance with the following ASTM (ASTM International)
standards:
— ASTM E1136, SRTT P195/75R14;
— ASTM F2870, SRTT 315/70 R 22.5 - 154/150 L;
— ASTM F2871, SRTT 245/70 R 19.5 - 136/134 M;
— ASTM F2872, SRTT 225/75 R 16 C - 116/114 S;
— ASTM F2493, SRTT P225/60R16 97 S;
— ASTM F3677, SRTT 315/70 R 22.5 SW - 154/150 L;
— ASTM F3678, SRTT 245/70 R 19.5 SW - 136/134 M;
3.8
control tyre
C
tyre set (3.5) that is part of an evaluation program
Note 1 to entry: It is an intermediate set of tyres which is used when the candidate tyre and the reference tyre cannot
be directly compared on the same vehicle.
3.9
braking test
series of a specified number of ABS-braking test runs (3.4) of the same tyre repeated within a short time frame
3.10
mean fully developed deceleration
mfdd
average deceleration calculated on the basis of the measured distance recorded when decelerating a vehicle
between two specified speeds
ISO/DIS 18106:2024(en)
3.11
acceleration test
series of a specified number of traction controlled acceleration test runs (3.4) of the same tyre repeated
within a short time frame
3.12
acceleration force of a tyre
longitudinal force resulting from acceleration torque application
Note 1 to entry: It is expressed in newtons, N.
3.13
acceleration force coefficient of a tyre
AFC
ratio of acceleration force to vertical load
3.14
average acceleration
AA
average acceleration calculated on the basis of the measured distance recorded when accelerating a vehicle
between two specified speeds
3.15
Snow Grip Index
SG
ratio between the performance of the candidate tyre to the performance of the proper standard reference
test tyre
3.16
loaded radius
distance from wheel axis of rotation to supporting surface (ground) at a given load and stated inflation
pressure
4 Test methods
4.1 Braking on snow method for passenger car tyres
4.1.1 General
Snow performance is based on a test method by which the mean fully developed deceleration in a braking
test, of a candidate tyre is compared to that of a standard reference test tyre.
The relative performance shall be indicated by a Snow Grip Index (SG).
4.1.2 Test course
The braking tests shall be done on a flat test surface of sufficient length and width, with a maximum 2 %
gradient, covered with packed snow.
The snow surface shall be composed of a hard packed snow base at least 3 cm thick and a surface layer of
medium packed and prepared snow about 2 cm thick.
The air temperature, measured about one meter above the ground, shall be between −2 °C and −15 °C; the
snow temperature, measured at a depth of about one centimetre, shall be between −4 °C and −15 °C.
It is recommended to avoid direct sunlight, large variations of sunlight or humidity, as well as wind.
The snow compaction index measured according to ASTM F1805 by using a CTI penetrometer shall be
between 75 and 85.
ISO/DIS 18106:2024(en)
The candidate tyre should be tested in the same slope and snow compaction condition as the reference tyre
to avoid any advantage or disadvantage for the candidate tyre.
4.1.3 Vehicle
The test shall be conducted with a standard production vehicle in good running order and equipped with ABS.
The vehicle used shall be such that the loads on each wheel are appropriate to the tyres being tested. Several
different tyre set can be tested on the same vehicle.
4.1.4 Standard reference test tyre
The proper reference tyre to be used to evaluate passenger car tyre snow grip performance is ASTM E1136,
SRTT P195/75R14 ASTM F2493, SRTT P225/60R16 97S.
4.1.5 Tyres preparation
Fit the test tyres on rims as per ISO 4000-1 using conventional mounting methods. Ensure proper bead
seating by the use of a suitable lubricant. Excessive use of lubricant should be avoided to prevent slipping of
the tyre on the wheel rim.
The tyres should be prepared prior to testing to remove spew, compound nodules or flashes resulting from
the moulding process. The tyre surface in contact with snow shall be clean before performing a test.
Tyres shall be conditioned at the outdoor ambient temperature at least two hours before their mounting for
tests. Tyre pressures shall then be adjusted to the values specified for the test.
In case a vehicle cannot accommodate both the reference and candidate tyres, a third tyre (“control” tyre)
may be used as an intermediate. First, test the control tyre against the reference on a suitable vehicle, then
test the candidate tyre against the control on the other vehicle.
4.1.6 Tyre load
The vehicle load shall be such that the resulting loads on the tyres are between 60 % and 90 % of the load
corresponding to the tyre load index.
4.1.7 Tyre inflation pressure
The cold inflation pressure shall be 240 kPa.
4.1.8 Instrumentation
The vehicle shall be fitted with calibrated sensors suitable for measurements in winter conditions. There
shall be a data acquisition system to store measurements.
The accuracy of measurement sensors and systems shall be such that the relative uncertainty of the
measured or computed mean fully developed decelerations is less than 1 %.
4.1.9 Testing order and sequences
For every candidate tyre and the standard reference test tyre, ABS-braking test runs shall be repeated a
minimum of six times.
The zones where ABS-braking is fully applied shall not overlap.
When a new set of tyres is tested, the runs are performed after shifting aside the vehicle trajectory in order
not to brake on the tracks of the previous tyre.
When it is no longer possible not to overlap full ABS-braking zones, the test course shall be re-groomed.

ISO/DIS 18106:2024(en)
Order of testing:
— If only one candidate tyre has to be evaluated, the order of testing shall be as follows:
Ri - T - Rf
where
Ri is the initial test of the SRTT;
Rf is the repeat test of the SRTT;
T is the test of the candidate tyre to be evaluated.
— A maximum of two candidate tyres (T1 and T2) may be tested before repeating the SRTT test, for
example:
Ri - T1 - T2 - Rf
Required sequence is as follows:
— six SRTT repetitions, then shift aside to test next tyre on fresh surface;
— six Candidate one repetitions, then shift aside;
— six Candidate two repetitions, then shift aside;
— six SRTT repetitions, then shift aside.
The comparative tests of SRTT and candidate tyres shall be repeated on two different days.
4.1.10 Test procedure
Drive the vehicle at a speed not lower than 28 km/h.
When the measuring zone has been reached, the vehicle gear is set into neutr
...