ISO/FDIS 18106

Passenger car, commercial vehicle, truck and bus tyres — Methods for measuring snow grip performance — Loaded new tyres

ISO 18106:2016 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. ISO 18106:2016 applies to all passenger car, commercial vehicle, truck and bus tyres.

Pneumatiques pour voitures particulières, véhicules utilitaires, camions et autobus — Méthodes de mesurage de l´adhérence sur neige — Pneumatiques neufs en charge

ISO 18106:2016 spécifie la méthode de mesure de l'indice relatif de la performance d'adhérence sur neige d'un pneumatique candidat par rapport à un pneumatique de référence sous charge pour des pneumatiques neufs destinés aux voitures particulières, véhicules utilitaires, camions et autobus sur une surface de neige compactée. Les méthodes décrites dans la présente norme sont destinées à réduire la variabilité des mesurages de la performance. Il est nécessaire d'utiliser les pneumatiques de référence adaptés pour limiter la variabilité des méthodes d'essai. ISO 18106:2016 s'applique à tous les pneumatiques pour voitures particulières, véhicules utilitaires, camions et autobus.

General Information

• Status: Not Published
• ICS: 83.160.10 - Road vehicle tyres
• Technical Committee: ISO/TC 31 - Tyres, rims and valves
• Drafting Committee: ISO/TC 31/WG 8 - Methods for measuring snow and ice grip performance
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 29-Apr-2026
• Completion Date: 29-Apr-2026

Relations

• Revises: ISO 18106:2016 - Passenger car, commercial vehicle, truck and bus tyres — Methods for measuring snow grip performance — Loaded new tyres
• Effective Date: 28-Oct-2023

Overview

ISO/FDIS 18106 defines standardized methods for measuring the snow grip performance of loaded, new tyres designed for passenger cars, commercial vehicles, trucks, and buses. Developed by ISO Technical Committee 31, this standard aims to provide accurate, repeatable, and comparable measurements of tyre performance on packed snow surfaces. The implementation of consistent reference tyres and controlled testing environments underpins the reliability of snow grip performance indices. This benchmark is crucial for tyre manufacturers, certification bodies, and regulatory agencies focused on road safety and product quality in winter conditions.

Key Topics

• Scope of Application: Applies to all new tyres intended for use on passenger cars, light commercial vehicles, trucks, and buses.
• Snow Grip Performance Index: Measures the relative performance of a candidate tyre to a standard reference tyre under specific loaded conditions.
• Test Methods:
  • Braking on snow for passenger car and commercial vehicle tyres
  • Acceleration on snow for truck and bus tyres
• Reference and Control Tyres:
  • Use of standardized reference tyres is required to limit variability in results.
  • Control tyres may be used for vehicle compatibility where direct comparison is not possible.
• Test Course Requirements:
  • Flat, packed snow surfaces of defined thickness and compaction
  • Controlled air and snow temperatures to standardize test conditions
• Performance Validation:
  • Statistical analysis to ensure the repeatability and accuracy of results.
  • Defined sequence and repetitions for test runs to validate data.
• Test Reports:
  • Exemplary formats for reporting snow grip indices are included for clarity and documentation.

Applications

ISO/FDIS 18106 is utilized in several critical areas:

• Tyre Development and Certification: Enables manufacturers to validate snow grip performance when developing new tyre models or improving existing products, supporting claims of winter performance.
• Regulatory Compliance and Labelling: Provides a recognized methodology for meeting national and international regulatory requirements related to winter tyre use and labelling.
• Comparative Product Testing: Offers a basis for independent organizations to benchmark and compare tyres from multiple manufacturers on objective snow grip performance metrics.
• Quality Assurance: Assures end-users (fleets, transport operators, consumers) that tyre performance data for snow grip has been tested to a globally recognized standard.
• Safety Evaluation: Supports public safety initiatives by establishing minimum snow grip performance levels for tyres used in snowy climates.

Related Standards

Implementation and use of ISO/FDIS 18106 may require reference to additional standards, including:

• ISO 4000-1: Specifications for passenger car tyres and rims
• ISO 4209-1: Specifications for truck and bus tyres and rims
• ASTM F1805: Test method for single wheel driving traction in a straight line on snow- and ice-covered surfaces
• ASTM E1136, F2493, F2870, F2871, F2872, F3677, F3678: Standards for reference test tyres used in performance assessments

Practical Value

By adopting ISO/FDIS 18106, stakeholders gain a transparent, consistent approach for evaluating and communicating snow grip performance of tyres. This standard supports informed purchasing decisions, facilitates regulatory harmonization, and ultimately enhances road safety in winter driving scenarios. The reliance on precise definitions, controlled testing, and recognized reference tyres ensures that snow grip indices are meaningful, reproducible, and trusted across the industry.

Standards Content (Sample)

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
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
This document is circulated as received from the committee secretariat.
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
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
This document is circulated as received from the committee secretariat. BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
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
...

FINAL DRAFT
International
Standard
ISO/TC 31
Passenger car, commercial vehicle,
Secretariat: ANSI
truck and bus tyres — Methods for
Voting begins on:
measuring snow grip performance
2026-04-29
— Loaded new tyres
Voting terminates on:
2026-06-24
Pneumatiques pour voitures particulières, véhicules utilitaires,
camions et autobus — Méthodes de mesurage de l´adhérence sur
neige — Pneumatiques neufs en charge
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
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
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
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 (SRTT) .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 .5
4.1.12 Snow grip performance comparison 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 .8
4.2.3 Vehicle .8
4.2.4 Standard reference test tyre.8
4.2.5 Tyres preparation .8
4.2.6 Tyre load .8
4.2.7 Tyre inflation pressure .8
4.2.8 Instrumentation.9
4.2.9 Testing order and sequences .9
4.2.10 Test procedure.9
4.2.11 Data evaluation and presentation of results .9
4.2.12 Snow grip performance comparison 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 .10
4.3.3 Vehicle .10
4.3.4 Standard reference test tyre (SRTT) .11
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 .14
4.3.12 Snow grip performance comparison using a control tyre . 15
Annex A (informative) Example test report for a passenger car or commercial vehicle tyre .16
Annex B (informative) Example test report for a truck and bus tyre .18
Bibliography .20

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves.
This second edition cancels and replaces the first edition (ISO 18106:2016), which has been technically
revised.
The main changes are as follows:
— addition of the reference tyre ASTM F2493-24, SRTT P225/60R16;
— addition of new reference tyres ASTM F3677-23, SRTT 315/70R22.5 SW and ASTM F3678-25, SRTT
245/70R19.5 SW.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
The methods developed in this document are meant to reduce the variability of the tyre snow grip
performance measurement. The proper reference tyres must be used in order to limit the variability of the
testing method procedures.
v
FINAL DRAFT International Standard ISO/FDIS 18106:2026(en)
Passenger car, commercial vehicle, truck and bus tyres —
Methods for measuring snow grip performance — Loaded
new tyres
1 Scope
This document specifies the method for measuring the 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.
This document applies to all passenger car, commercial vehicle, truck and bus 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 4209-1, Truck and bus tyres and rims (metric series) — Part 1: Tyres
ASTM F1805-20, Standard Test Method for Single Wheel Driving Traction in a Straight Line on Snow- and Ice-
Covered Surfaces
ASTM F2872-25, Standard Specification for 225/75R16C 116/114S M+S Radial Light Truck Standard Reference
Test Tire
ASTM F2493-24, Standard Specification for P225/60R16 97S Radial Standard Reference Test Tire
ASTM F3677-23, Standard Specification for 315/70R22.5 154/150L Radial Truck Standard Reference Test Tire
SW
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
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”

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 are
produced, controlled and stored in accordance with the following ASTM standards:
— ASTM E1136-19, SRTT P195/75R14;
— ASTM F2870-23, SRTT 315/70 R 22.5 - 154/150 L;
— ASTM F2871-25, SRTT 245/70 R 19.5 - 136/134 M;
— ASTM F2872-25, SRTT 225/75 R 16 C - 116/114 S;
— ASTM F2493-24, SRTT P225/60R16 97 S;
— ASTM F3677-23, SRTT 315/70 R 22.5 SW - 154/150 L;
— ASTM F3678-25, 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 anti-lock braking system (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
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 of a tyre to its 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) in a test report format as shown in
Appendix A.
4.1.2 Test course
The braking tests shall be done on a flat test surface 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 shall be measured according to ASTM F1805-20 by using a CTI penetrometer.
The snow compaction index shall be between 75 and 85.

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 (SRTT)
The passenger car tyre snow grip performance shall be evaluated by using ASTM F2493-24, SRTT
P225/60R16 97S as the reference tyre.
4.1.5 Tyres preparation
Fit the test tyres on rims in accordance with ISO 4000-1 using conventional mounting methods. Ensure
proper bead seating by the use of a tyre industry accepted 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 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.

The order of testing is as follows.
— If only one candidate tyre must be evaluated, the order of testing shall be as shown in Formula (1):
R - T - R (1)
i f
where
R is the initial test of the SRTT;
i
R is the repeat test of the SRTT;
f
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
as shown in Formula (2):
R - T - T - R (2)
i 1 2 f
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 neutral, the brake pedal is depressed
sharply by a constant force sufficient to cause operation of the ABS on all wheels of the vehicle and to result
in stable deceleration of the vehicle and held down until the speed is lower than 8 km/h.
The mean fully developed deceleration between 25 km/h and 10 km/h shall be comp
...

Date: 2025-02-12
ISO/DISFDIS 18106:2024(en)
ISO/TC 31/WG 8
Secretariat: ANSI
Date: 2026-04-13
Passenger car, commercial vehicle, truck and bus tyres — Methods
for measuring snow grip performance — Loaded new tyres
Pneumatiques pour voitures particulièreparticulières, véhicules utilitaires, camions et autobus — Méthodes de
mesurage de l´adhérence sur neige — Pneumatiques neufs en charge
FDIS stage
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO'sISO’s member body in the country of the requester.
ISO Copyright Officecopyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Email:
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland.
ii
ii
ISO/DISFDIS 18106:20242026(en)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test methods . 4
4.1 Braking on snow method for passenger car tyres . 4
4.2 Braking on snow method for commercial vehicle tyres . 9
4.3 Acceleration on snow method for truck and bus tyres . 11
Annex A (informative) Example test report for a passenger car or commercial vehicle tyre . 19
Annex B (informative) Example test report for a truck and bus tyre . 22
Bibliography . 25

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO [had/had not] received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that this
may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 31, Tyres, rims and valves.
This second edition cancels and replaces the first edition (ISO 18106:2016), which has been technically
revised.
The main changes are as follows:
— — addition of the reference tyre ASTM F2493-24, SRTT P225/60R16 has been added;
— — theaddition of new reference tyres ASTM F3677-23, SRTT 315/70R22.5 SW and ASTM F3678-25,
SRTT 245/70R19.5 SW have been added.

Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
iv
ISO/DISFDIS 18106:20242026(en)
Introduction
The methods developed in this document are meant to reduce the variability of the tyre snow grip
performance measurement. The use of the proper reference tyres is necessarymust be used in order to limit
the variability of the testing method procedures.
v
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 document specifies the method for measuring the 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.
This document applies to all passenger car, commercial vehicle, truck and bus 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 4209--1, Truck and bus tyres and rims (metric series) — Part 1: Tyres
ASTM F1805-20, Standard Test Method for Single Wheel Driving Traction in a Straight Line on Snow- and Ice-
Covered Surfaces
ASTM E1136-19, Standard Specification for P195/75R14 Radial Standard Reference Test Tire
ASTM F2870-23, Standard Specification for 315/70R22.5 154/150L Radial Truck Standard Reference Test Tire
ASTM F2871-25, Standard Specification for 245/70R19.5 136/134M Radial Truck Standard Reference Test Tire
ASTM F2872-25, Standard Specification for 225/75R16C 116/114S M+S Radial Light Truck Standard Reference
Test Tire
ASTM F2493-24, Standard Specification for P225/60R16 97S Radial Standard Reference Test Tire
ASTM F3677-23, Standard Specification for 315/70R22.5 154/150L Radial Truck Standard Reference Test Tire
SW
ASTM F3678-25, 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.
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
3.1
passenger car tyre
tyres conforming to ISO 4000--1
3.2 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”
3.3 3.3
truck and bus tyre
tyres conforming to ISO 4209--1 and identified by:
a) a) a load index in single configuration higher or equal to 122; or
b) b) a load index in single configuration lower or equal to 121 and a speed symbol lower or equal
to “M”
3.4 3.4
test run
single pass of a loaded tyre over a given test surface
3.5 3.5
tyre set
group of two or four same tyres
3.6 3.6
candidate tyre
T
test tyre set (3.5(3.5)) that is part of an evaluation program
3.7 3.7
reference tyre
R
special test tyre set (3.5(3.5),), also known as a Standard Reference Test Tyrestandard 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 are
produced, controlled and stored in accordance with the following ASTM (ASTM International) standards:
— — ASTM E1136-19, SRTT P195/75R14;
— — ASTM F2870-23, SRTT 315/70 R 22.5 - 154/150 L;
— — ASTM F2871-25, SRTT 245/70 R 19.5 - 136/134 M;
— — ASTM F2872-25, SRTT 225/75 R 16 C - 116/114 S;
ISO/DISFDIS 18106:20242026(en)
— — ASTM F2493-24, SRTT P225/60R16 97 S;
— — ASTM F3677-23, SRTT 315/70 R 22.5 SW - 154/150 L;
— — ASTM F3678-25, SRTT 245/70 R 19.5 SW - 136/134 M.
3.8 3.8
control tyre
C
tyre set (3.5(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 3.9
braking test
series of a specified number of Antianti-lock Braking Systembraking system (ABS)-) braking test runs
(3.4(3.4)) of the same tyre repeated within a short time frame
3.10 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
3.11 3.11
acceleration test
series of a specified number of traction-controlled acceleration test runs (3.4(3.4)) of the same tyre repeated
within a short time frame
3.12 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 3.13
acceleration force coefficient of a tyre
AFC
ratio of acceleration force of a tyre to its vertical load
3.14 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 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 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) in a test report format as shown in
Appendix AAppendix A.
4.1.2 Test course
The braking tests shall be done on a flat test surface 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 shall be measured according to ASTM F1805-20 by using a CTI penetrometer. The
snow compaction index shall be between 75 and 85.
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 (SRTT)
The passenger car tyre snow grip performance shall be evaluated by using ASTM F2493-24, SRTT
P225/60R16 97S as the reference tyre.
ISO/DISFDIS 18106:20242026(en)
4.1.5 Tyres preparation
Fit the test tyres on rims in accordance with ISO 4000--1 using conventional mounting methods. Ensure
proper bead seating by the use of a tyre industry accepted 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 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.
The order of testing is as follows.
— — If only one candidate tyre must be evaluated, the order of testing shall be as follows:shown in Formula
(1):
R - T - R (1)
i f
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.
— R is the initial test of the SRTT;
i
R is the repeat test of the SRTT;
f
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:
as shown in Formula (2):
R - T - T - R (2)
i 1 2 f
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 neutral, the brake pedal is depressed
sharply by a constant force sufficient to cause operation of the ABS on all wheels of the vehicle and to result
in stable deceleration of the vehicle and held down until the speed is lower than 8 km/h.
The mean fully developed deceleration between 25 km/h and 10 km/h shall be computed from distance,
speed, or deceleration measurements.
The mean fully developed deceleration, MFDD, is given by Formula (3)Formula (1)::
(1)
2 2
𝑆𝑆𝑓𝑓 −𝑆𝑆𝑖𝑖
| |
2𝐷𝐷
(3)
where
D is the distance covered between Si and Sf, in m;
ISO/DISFDIS 18106:20242026(en)
Si is the initial speed, in m/s;
Sf is the final speed, in m/s.
D is the distance covered between Si and Sf, in m;
Si is the initial speed, in m/s;
Sf is the final speed, in m/s.
4.1.11 Data evaluation and presentation of results
4.1.11.1 Coefficient of variation
For each tyre and each braking test, the mean and the standard deviation of the MFDD shall be computed and
reported.
The coefficient of variation, CV, of a tyre braking test shall be computed as given in Formula (4)Formula (2)::
(2)
𝑆𝑆
tyre
SRTTCV =
tyre
𝑀𝑀
tyre
(4)
where
S is the standard deviation;
M is the mean.
4.1.11.2 Standard reference test tyre (SRTT) weighted variance
Weighted averages (wa) of two successive tests of the SRTT shall be computed, taking into account the number
of candidate tyres in between.
is the mean MFDD in the first test of the reference tyre and R is the mean MFDD in the second test of the
If R
i f
reference tyre, the following operations shall be performed, according to Table 1Table 1.
Table 1 — Calculation of weighted averages
Set of candidate tyres Set of candidate
between two successive tyres to be then “wa
runs of the reference tyre qualified
1  Ri -T1 – Rf T1 wa = 1/2 (Ri + Rf)
2  R -T – T – R T1 wa = 2/3 Ri + 1/3 Rf
i 1 2 f
T2 wa = 1/3 Ri + 2/3 Rf
“Ta” (a = 1, 2) is the average of the mean MFDD values for a test of a candidate tyre.
4.1.11.3 Snow grip index (SG)
The SG in percent of a candidate tyre shall be computed as given in Formula (5)Formula (3)::
(3)
𝑀𝑀
𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐
SG = f
candidate
𝑤𝑤𝑤𝑤
𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆
(5)
f = 0,980 when tested with ASTM F2493-24, SRTT P225/60R16 97S.
f = 1,000 when tested with ASTM E1136-19, SRTT P195/75R14.

where
SG is the snow grip index;
M is the mean;
wa is the weighted average.
4.1.11.4 Statistical validation
The sets of repeats of measured or computed MFDD for each tyre should be examined for normality, drift,
eventual outliers.
The consistency of the means and standard deviations of successive braking tests of SRTT should be examined.
The means of two successive SRTT braking tests shall not differ by more than 5 %.
The coefficient of variation of any braking test shall not be higher than 6 %.
If those conditions are not met, tests shall be performed again after re-grooming the test course.
The SRTT tyres shall be discarded if there is irregular wear or damage or when the performance appears to
have been deteriorated.
4.1.12 Snow grip performance comparison using a control tyre
4.1.12.1 General
In the case where the candidate tyres cannot be fitted to the same vehicle as the SRTT, for example, due to tyre
size, inability to achieve required loading and so on, comparison shall be made using intermediate tyres,
hereinafter referred to as “control tyres”, and two different vehicles.
One vehicle shall be capable of being fitted with the SRTT and the control tyre and the other vehicle shall be
capable of being fitted with the control tyre and the candidate tyre.
4.1.12.2 Snow grip index (SG) calculation in case of a control tyre
The SG of the control tyre relative to the SRTT (SG1) and of the candidate tyre relative to the control tyre (SG2)
shall be established using the procedure in 4.1.24.1.2 to 4.1.11.44.1.11.4.
The SG of the candidate tyre relative to the SRTT shall be the product of the two resulting snow grip indices
that is SG1 × SG2.
4.1.12.3 Boundary conditions
The ambient conditions shall be comparable. All tests shall be completed within the same day.
ISO/DISFDIS 18106:20242026(en)
The same set of control tyres shall be used for comparison with the SRTT and with the candidate tyre and shall
be fitted in the same wheel positions.
A control tire set is a group of identical tyres made in the same factory during the same production week.
Control tyres that have been used for testing shall subsequently be stored under the same conditions as
required for the SRTT.
The SRTT and control tyres shall be discarded if there is irregular wear or damage or when the performance
appears to have been deteriorated.
4.2 Braking on snow method for commercial vehicle tyres
4.2.1 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 an SG in a test report format as shown in Annex AAnnex A.
4.2.2 Test course
The requirements specified in 4.1.24.1.2 apply.
4.2.3 Vehicle
The requirements specified in 4.1.34.1.3 apply.
4.2.4 Standard reference test tyre
Commercial vehicle tyre snow grip performance shall be evaluated by using ASTM F2872-25, SRTT
225/75R16C 116/114S as the refe
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