Regulation No. 117-02

Name:Regulation No. 117-02
Description:Tyres with Regard to Rolling Sound Emissions.
Official Title:Uniform Provisions Concerning the Approval of: Tyres with Regard to Rolling Sound Emissions and to Adhesion on Wet Surfaces and/or to Rolling Resistance.
Country:ECE - United Nations
Date of Issue:2011-09-15
Amendment Level:02 Series, Supplement 9
Number of Pages:134
Vehicle Types:Car, Component, Light Truck, Trailer
Subject Categories:Steering, Wheels and Tyres
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Keywords:

tyre, test, tyres, approval, regulation, vehicle, reference, surface, candidate, rolling, load, snow, speed, paragraph, force, temperature, sound, braking, wet, index, grip, coefficient, series, set, average, control, class, measured, method, amendments, type, conditions, srtt, requirements, annex, standard, number, testing, resistance, pressure, measurement, drum, calculated, stage, means, measurements, track, performance, maximum, level

Text Extract:

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E/ECE/324
) Rev.2/Add.116/Rev.4/Amend.1
E/ECE/TRANS/505 )
February 22, 2017
STATUS OF UNITED NATIONS REGULATION
ECE 117-02
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF:
TYRES WITH REGARD TO ROLLING SOUND EMISSIONS
AND/OR TO ADHESION ON WET SURFACES
AND/OR TO ROLLING RESISTANCE
Incorporating:
00 series of amendments
Date of Entry into Force: 06.04.05
Corr. 1 to the 00 series of amendments
Dated: 15.07.05
Corr. 2 to the 00 series of amendments
Dated: 01.08.06
01 series of amendments
Date of Entry into Force: 02.02.07
Corr. 1 to the 01 series of amendments (including Erratum)
Dated: 09.05.07
Corr. 2 to the 01 series of amendments
Dated: 07.08.08
Corr. 3 to the 01 series of amendments
Date of Entry into Force: 10.03.09
02 series of amendments
Date of Entry into Force: 30.01.11
Corr. 1 to the 02 series of amendments
Dated: 30.01.11
Corr. 2 to the 02 series of amendments
Dated: 22.06.11
Corr. 3 to the 02 series of amendments
Dated: 22.06.11
Supplement 1 to the 02 series of amendments
Date of Entry into Force: 18.11.12
Supplement 2 to the 02 series of amendments
Date of Entry into Force: 15.07.13
Supplement 3 to the 02 series of amendments
Date of Entry into Force: 03.11.13
Supplement 4 to the 02 series of amendments
Date of Entry into Force: 13.02.14
Corr. 4 to the 02 series of amendments
Dated: 12.03.14
Supplement 5 to the 02 series of amendments
Date of Entry into Force: 10.06.14
Supplement 6 to the 02 series of amendments
Date of Entry into Force: 09.10.14
Supplement 7 to the 02 series of amendments
Date of Entry into Force: 08.10.15
Supplement 8 to the 02 series of amendments
Date of Entry into Force: 20.01.16
Supplement 9 to the 02 series of amendments
Date of Entry into Force: 09.02.17

REGULATION NO. 117-02
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF TYRES WITH REGARD TO
ROLLING SOUND EMISSIONS AND/OR TO ADHESION ON WET SURFACES
AND/OR TO ROLLING RESISTANCE
REGULATION
CONTENTS
1.
Scope
2.
Definitions
3.
Application for approval
4.
Markings
5.
Approval
6.
Specifications
7.
Modifications of the type of pneumatic tyre and extension of approval
8.
Conformity of production
9.
Penalties for non-conformity of production
10.
Production definitively discontinued
11.
Names and addresses of Technical Services responsible for conducting approval tests, and of
Type Approval Authorities
12.
Transitional provisions
ANNEXES
Annex 1
− Communication
Annex 2 − Appendix 1: Example of approval marks
Appendix 2:
Approval according to Regulation No. 117 coincident with approval to
Regulation No. 30 or 54
Appendix 3: Extensions to combine approvals issued in accordance with
Regulations Nos. 117, 30 or 54
Appendix 4: Extensions to combine approvals issued in accordance with
Regulation No. 117
Annex 3
− Coast-by test method for measuring tyre-rolling sound emission
Appendix 1:
Test report
Annex 4
− Specifications for the test site

REGULATION NO. 117-02
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF TYRES WITH REGARD TO
ROLLING SOUND EMISSIONS AND/OR TO ADHESION ON WET SURFACES
AND/OR TO ROLLING RESISTANCE
1. SCOPE
1.1. This Regulation applies to new pneumatic tyres of Classes C1, C2 and C3 with regard to
their sound emissions, rolling resistance and to adhesion performance on wet surfaces (wet
adhesion). It does not, however, apply to:
1.1.1. Tyres designed as "Temporary use spare tyres" and marked "Temporary use only";
1.1.2. Tyres having a nominal rim diameter code ≤10 (or ≤254mm) or ≥25 (or ≥635mm);
1.1.3. Tyres designed for competitions;
1.1.4. Tyres intended to be fitted to road vehicles of categories other than M, N and O ;
1.1.5. Tyres fitted with additional devices to improve traction properties (e.g. studded tyres);
1.1.6. Tyres with a speed rating less than 80km/h (speed symbol F);
1.1.7. Tyres designed only to be fitted to vehicles registered for the first time before
October 1, 1990.
1.1.8. Professional off-road tyres.
1.2. Contracting Parties shall issue or accept approvals to rolling sound and/or wet adhesion
and/or rolling resistance.
2. DEFINITIONS
For the purpose of this Regulation, in addition to the definitions contained in
Regulations Nos. 30 and 54, the following definitions apply.

2.7. "Representative tyre size" means the tyre size which is submitted to the test described in
Annex 3 to this Regulation with regard to rolling sound emissions, or Annex 5 for adhesion
on wet surfaces or Annex 6 for rolling resistance to assess the conformity for the Type
Approval of the type of tyre, or Annex 7 for use in severe snow conditions.
2.8. "Temporary-use spare tyre" means a tyre different from a tyre intended to be fitted to any
vehicle for normal driving conditions; but intended only for temporary use under restricted
driving conditions.
2.9. "Tyres designed for competition" means tyres intended to be fitted to vehicles involved in
motor sport competition and not intended for non-competitive on-road use.
2.10. "Normal tyre" means a tyre intended for normal on-road use.
2.11. "Reinforced tyre" or "extra load tyre" of Class C1 means a tyre structure designed to
carry more load at a higher inflation pressure than the load carried by the corresponding
standard version tyre at the standard inflation pressure as specified in ISO 4000-1:2010 .
2.12. "Traction tyre" means a tyre in Class C2 or C3 bearing the inscription TRACTION and
intended to be fitted primarily to the drive axle(s) of a vehicle to maximize force transmission
in various circumstances.
2.13. "Snow tyre" means a tyre whose tread pattern, tread compound or structure is primarily
designed to achieve in snow conditions a performance better than that of a normal tyre with
regard to its ability to initiate or maintain vehicle motion.
2.13.1. "Snow tyre for use in severe snow conditions" means a snow tyre whose tread pattern,
tread compound or structure is specifically designed to be used in severe snow conditions
and that fulfils the requirements of Paragraph 6.4. of this Regulation.
2.14. "Special use tyre" means a tyre intended for mixed use both on- and off-road or for other
special duty. These tyres are primarily designed to initiate and maintain the vehicle in
motion in off-road conditions.
2.15. "Professional off-road tyre" is a special use tyre primarily used for service in severe
off-road conditions.
2.16. "Tread depth" means the depth of the principal grooves.
2.16.1. "Principal grooves" means the wide circumferential grooves positioned in the central zone
of the tyre tread, which, in the case of passenger and light truck (commercial) tyres, have
the treadwear indicators located in the base.
2.17. "Void to fill ratio" means the ratio between the area of voids in a reference surface and the
area of this reference surface calculated from the mould drawing.

2.20. Rolling Resistance Measurement – Specific Definitions
2.20.1. Rolling Resistance F
Loss of energy (or energy consumed) per unit of distance travelled .
2.20.2. Rolling Resistance Coefficient C
Ratio of the rolling resistance to the load on the tyre .
2.20.3. New Test Tyre
A tyre which has not been previously used in a rolling deflected test that raises its
temperature above that generated in rolling resistance tests, and which has not previously
been exposed to a temperature above 40°C
2.20.4. Laboratory Control Tyre
Tyre used by an individual laboratory to control machine behaviour as a function of time .
2.20.5. Capped Inflation
Process of inflating the tyre and allowing the inflation pressure to build up, as the tyre is
warmed up while running.
2.20.6. Parasitic Loss
Loss of energy (or energy consumed) per unit distance excluding internal tyre losses,
attributable to aerodynamic loss of the different rotating elements of the test equipment,
bearing friction and other sources of systematic loss which may be inherent in the
measurement.
2.20.7. Skim Test Reading
Type of parasitic loss measurement, in which the tyre is kept rolling without slippage, while
reducing the tyre load to a level at which energy loss within the tyre itself is virtually zero.
2.20.8. Inertia or Moment of Inertia
Ratio of the torque applied to a rotating body to the rotational acceleration of this body .

3.1.9. Category of use (normal, snow, or special);
3.1.10. A list of tyre size designations covered by this application.
3.2. The application for approval shall be accompanied (in triplicate) by:
3.2.1. Details of the major features, with respect to the effects on the performance (i.e. rolling
sound emission level, adhesion on wet surfaces, rolling resistance and snow grip) of the
tyres, including the tread pattern, included in the designated range of tyre sizes. This may
be by means of descriptions supplemented by technical data, drawings, photographs and
Computer Tomography (CT), and must be sufficient to allow the Type Approval Authority or
technical service to determine whether any subsequent changes to the major features will
adversely affect the tyre performance. The effects of changes to minor details of tyre
construction on tyre performances will be evident and determined during checks on
conformity of production;
3.2.2. Drawings or photographs of the tyre sidewall, showing the information given in
Paragraph 3.1.8. above and the approval marking referred to in Paragraph 4., shall be
submitted once the production has been established, but no later than one year after the
date of granting of Type Approval.
3.2.3. In the case of applications relating to special use tyres, a copy of the mould drawing of the
tread pattern shall be supplied in order to allow verification of the void-to-fill ratio.
3.3. At the request of the Type Approval Authority, the applicant shall submit samples of tyres for
test or copies of test reports from the technical services, communicated as given in
Paragraph 11 of this Regulation.
3.4. With regard to the application, testing may be confined to a worst case selection, at the
discretion of the Type Approval Authority or designated Technical Service.
4. MARKINGS
4.1. All tyres constituting the type of tyre shall be marked as prescribed by either
Regulation No. 30 or 54, as applicable.
4.2. In particular tyres shall bear :
4.2.1. The manufacturer's name or the Brand name/trademark;
4.2.2. The trade description/commercial name (see Paragraph 2.4. of this Regulation). However,
the trade description is not required when it coincides with the Brand name/trademark;
4.2.3. The tyre size designation;
4.2.4. The inscription "REINFORCED" (or alternatively "EXTRA LOAD") if the tyre is classified as
reinforced;
4.2.5. The inscription "TRACTION" if the tyre is classified as "traction tyre";

5.3.1.2. The prefix shall identify the series of amendments of the prescription on tyre performances
for the relevant Regulation, e.g. 02S2 to identify the second series of amendments on tyre
road rolling sound emissions at Stage 2 or 02S1WR1 to identify the second series of
amendments on tyre road rolling sound emissions at Stage 1, tyre adhesion on wet surfaces
and rolling resistance at Stage 1 (see Paragraph 6.1. below for Stage 1 and Stage 2
definitions). No identification to the series of amendments shall be required if the relevant
Regulation is in its original form.
5.3.2. The following suffixes have been already reserved to identify specific Regulations on tyre
performance parameters:
S
W
R
To identify additional conformity to the requirements on tyre rolling sound emissions;
To identify additional conformity to the requirements on tyre adhesion on wet
surfaces;
To identify additional conformity to the requirements on tyre rolling resistance.
Taking into account that two stages are defined for rolling sound and rolling resistance
specifications in Paragraphs 6.1. and 6.3. below, S and R will be followed either by the
Suffix "1" for compliance to Stage 1 or by the Suffix "2" for compliance to Stage 2.
5.4. In the space referred to in Paragraph 4.3. and in accordance with the requirements of
Paragraph 4.4. above there shall be affixed to every tyre size, conforming to the type of tyre
approved under this Regulation, an international approval mark consisting of:
5.4.1. A circle surrounding the Letter "E" followed by the distinguishing number of the country
which has granted approval ; and
5.4.2. The approval number, which shall be placed close to the circle prescribed in
Paragraph 5.4.1. above either above or below the "E" or to the left or right of that letter.

6. SPECIFICATIONS
6.1. Rolling sound emission limits, as measured by the method described in Annex 3 to this
Regulation.
6.1.1. For Class C1 Tyres, the rolling sound emission value shall not exceed the values pertinent
to the applicable stage given below. These values refer to the nominal section width as
given in Paragraph 2.17.1.1. of Regulation No. 30:
Stage 1
Nominal Section Width
Limit dB(A)
145 and lower 72
Over 145 up to 165 73
Over 165 up to 185 74
Over 185 up to 215 75
Over 215 76
The above limits shall be increased by 1dB(A) for extra load tyres or reinforced tyres and by
2dB(A) for "special use tyres".
Stage 2
Nominal Section Width
Limit dB(A)
185 and lower 70
Over 185 up to 245 71
Over 245 up to 275 72
Over 275 74
The above limits shall be increased by 1dB(A) for "snow tyre for use in severe snow
conditions" , extra load tyres or reinforced tyres, or any combination of these classifications.

6.1.3. For Class C3 Tyres, the rolling sound emission value with reference to its category of use
(see Paragraph 2.1. above) shall not exceed the values pertinent to the applicable stage
given below:
Stage 1
Category of use
Limit dB(A)
Normal tyre 76
Snow tyre 78
Special use tyre 79
Stage 2
Category of use
Other
Limit dB(A)
Traction Tyres
Normal tyre 73 75
73 75
Snow tyre
Snow tyre for use in
severe snow conditions
74 76
Special use tyre 75 77
6.2. The wet grip performance will be based on a procedure that compares either peak brake
force coefficient ("pbfc") or mean fully developed deceleration ("mfdd") against values
achieved by a standard reference test tyre (SRTT). The relative performance shall be
indicated by a wet grip index (G).

6.3. Rolling resistance coefficient limits, as measured by the method described in Annex 6 to this
Regulation.
6.3.1. The maximum values for Stage 1 for the rolling resistance coefficient shall not exceed the
following (value in N/kN is equivalent to value in kg/tonne):
Tyre class
Max value (N/kN)
C1 12.0
C2 10.5
C3 8.0
For "snow tyre for use in severe conditions", the limits shall be increased by 1N/kN.
6.3.2. The maximum values for Stage 2 for the rolling resistance coefficient shall not exceed the
following (value in N/kN is equivalent to value in kg/tonne):
Tyre class
Max value (N/kN)
C1
10.5
C2
9.0
C3
6.5
For snow tyre for use in severe snow conditions",, the limits shall be increased by 1N/kN.

6.7. In order to be classified as a 'professional off-road tyre', a tyre shall have all of the following
characteristics:
(a)
For C1 and C2 Tyres:
i) A tread depth ≥11mm;
ii)
iii)
A void-to-fill ratio ≥35%;
A maximum speed rating of ≤Q.
(b)
For C3 Tyres:
i) A tread depth ≥16mm;
ii)
iii)
A void-to-fill ratio ≥35%;
A maximum speed rating of ≤K.
7. MODIFICATIONS OF THE TYPE OF TYRE AND EXTENSION OF APPROVAL
7.1. Every modification of the type of tyre, which may influence the performance characteristics
approved in accordance with this Regulation, shall be notified to the Type Approval
Authority which approved the type of tyre. The authority may either:
7.1.1. Consider that the modifications are unlikely to have any appreciable adverse effect on the
performance characteristics approved and that the tyre will comply with the requirements of
this Regulation; or
7.1.2. Require further samples to be submitted for test or further test reports from the designated
Technical Service.
7.1.3. Confirmation or refusal of approval, specifying the modifications, shall be communicated by
the procedure given in Paragraph 5.3. of this Regulation to the Parties to the Agreement
which apply this Regulation.
7.1.4. The Type Approval Authority granting the extension of approval shall assign a series
number for such an extension which shall be shown on the communication form.

10. PRODUCTION DEFINITIVELY DISCONTINUED
If the holder of an approval completely ceases to manufacture a type of tyre approved in
accordance with this Regulation, he shall so inform the Type Approval Authority, which
granted the approval. Upon receiving the relevant communication that Authority shall inform
thereof the other Parties to the 1958 Agreement applying this Regulation by means of a
communication form conforming to the model in Annex 1 to this Regulation.
11. NAMES AND ADDRESSES OF TECHNICAL SERVICES RESPONSIBLE FOR
CONDUCTING APPROVAL TESTS OF TYPE APPROVAL AUTHORITIES
11.1. The Contracting Parties to the 1958 Agreement which apply this Regulation shall
communicate to the United Nations Secretariat, the names and addresses of the Technical
Services responsible for conducting approval tests and, where applicable, of the approved
test laboratories and of the Type Approval Authorities which grant approval and to which
forms certifying approval or extension of approval or refusal of approval or withdrawal of
approval, or production definitively discontinued, issued in other countries, are to be sent.
11.2. The Contracting Parties to the 1958 Agreement which apply this Regulation may designate
laboratories of tyre manufacturers as approved test laboratories.
11.3. Where a Contracting Party to the 1958 Agreement applies Paragraph 11.2. Above, it may, if
it so desires, be represented at the tests by one or more persons of its choice.
12. TRANSITIONAL PROVISIONS
12.1. As from the date of entry into force of the 02 series of amendments to this Regulation,
Contracting Parties applying this Regulation shall not refuse to grant approval under this
Regulation for a type of tyre if the tyre complies with the requirements of the 02 series of
amendments, including the Stage 1 or Stage 2 rolling sound requirements set out in
Paragraphs 6.1.1. to 6.1.3. of this Regulation, the requirements for wet grip performance set
out in Paragraph 6.2.1. of this Regulation, and the Stage 1 or Stage 2 rolling resistance
requirements set out in Paragraph 6.3.1. or 6.3.2. of this Regulation.
12.2. As from November 1, 2012, Contracting Parties applying this Regulation shall refuse to
grant approval if the tyre type to be approved does not meet the requirements of this
Regulation as amended by the 02 series of amendments, and shall, in addition, refuse to
grant approval if the Stage 2 rolling sound requirements set out in Paragraphs 6.1.1. to
6.1.3. of this Regulation, the requirements for wet grip performance set out in
Paragraph 6.2.1. of this Regulation, and the Stage 1 rolling resistance requirements set out
in Paragraph 6.3.1. of this Regulation are not complied with.
12.3. As from November 1, 2014, Contracting Parties applying this Regulation may refuse to allow
the sale or entry into service of a tyre which does not meet the requirements of this
Regulation as amended by the 02 series, and which does not meet the requirements of this
Regulation as amended by the 02 series of amendments including the wet grip performance
requirements set out in Paragraph 6.2.1. of this Regulation.
12.4. As from November 1, 2016, Contracting Parties applying this Regulation shall refuse to
grant approvals if the tyre type to be approved does not meet the requirements of this
Regulation as amended by the 02 series of amendments including the Stage 2 rolling
resistance requirements set out in Paragraph 6.3.2. of this Regulation and the wet grip
requirements set out in Paragraphs 6.2.2. and 6.2.3. of this Regulation.

ANNEX 1
COMMUNICATION
(Maximum format: A4 (210 × 297mm))
issued by:
Name of administration:
.............................................
.............................................
.............................................
concerning
APPROVAL GRANTED
APPROVAL EXTENDED
APPROVAL REFUSED
APPROVAL WITHDRAWN
PRODUCTION DEFINITIVELY DISCONTINUED
of a type of tyre with regard to "rolling sound emission level" and/or "adhesion performance on wet
surfaces" and/or "rolling resistance" pursuant to Regulation No. 117.
Approval No. ............................................ Extension No. .................................................
1. Manufacturer's name and address: .....................................................................................................
2. If applicable, name and address of manufacturer's representative: ...................................................
3. "Tyre class" and "category of use" of the type of tyre: ........................................................................
3.1. Snow tyre for use in severe snow conditions (Yes/No)
3.2. Traction tyre (Yes/No)
4. Tyre type designation:
4.1. Brand-name(s)/trademark(s) of the type of tyre: .................................................................................
4.2. Trade description(s)/Commercial name(s) of the type of tyre: ............................................................
5. Technical Service and, where applicable, test laboratory approved for purposes of approval or of
verification of conformity tests: ............................................................................................................

ANNEX 2
APPENDIX 1
EXAMPLE OF APPROVAL MARKS
Arrangements of Approval Marks
(See Paragraph 5.4. of this Regulation)
Approval According to Regulation No. 117
Example 1
a ≥12mm
The above approval mark, affixed to a tyre shows that a tyre concerned has been approved in the
Netherlands (E4) pursuant to Regulation No. 117 (marked by S2 (rolling sound at Stage 2) only), under
approval number 0212345. The first two digits of the approval number (02) indicate that the approval was
granted according to the requirements 02 series of amendments of this Regulation.
Example 2
a ≥12mm
The above approval mark shows that the tyre concerned has been approved in the Netherlands (E4)
pursuant to Regulations Nos. 117 (marked by S1 (rolling sound at Stage 1) W (wet adhesion)) and
R1 (Rolling resistance at Stage 1) under approval number 0212345. This indicates that the approval is
for S1WR1. The first two digits of the approval number (02) indicate that the approval was granted
according to the requirements of the 02 series of amendments of this Regulation.

Example 2
a ≥12mm
The above approval mark shows that the tyre concerned has been approved in the Netherlands (E4)
pursuant to Regulation No. 117 (marked by S2WR2 (rolling sound at Stage 2 wet adhesion and rolling
resistance at Stage 2)), under approval number 0212345 and Regulation No. 30 under approval
number 0236378. The first two digits of the approval number (02) indicate that the approval was granted
according to the 02 series of amendments and Regulation No. 30 included the 02 series of amendments.

Example 4
a ≥12mm
The above approval mark shows that the tyre concerned has been approved in the Netherlands (E4)
pursuant to Regulation No. 117 and the 02 series of amendments under approval number 0212345
(marked by S2R2), and Regulation No. 54. This indicates that the approval is for rolling sound
Stage 2 (S2) and rolling resistance Stage 2. The first two digits of Regulation No. 117 approval number
(02) in conjunction with "S2R2" indicate that the first approval was granted in accordance with
Regulation No. 117 which included the 02 series of amendments. The first two digits of
Regulation No. 54 (00) indicate that this Regulation was in its original form.

Example 2
a ≥12mm
The above approval mark shows that the tyre concerned has been initially approved in the
Netherlands (E4) pursuant to Regulation No. 30 and the 02 series of amendments under approval
number 0236378. This indicates that the approval is for S1 (rolling sound at Stage 1) W (wet adhesion)
and R2 (rolling resistance at Stage 2). The S1WR2 preceded by (02) indicates that it has had its
approval extended under Regulation No. 117 which included the 02 series of amendments. The first two
digits of the approval number (02) indicate that the approval was granted according to Regulation No. 30
(02 series of amendments). The addition (+) sign indicates that the first approval was granted in
accordance with Regulation No. 30 and has been extended to include Regulation No. 117 approval(s)
(02 series of amendments).

Example 3
a ≥12mm
The above approval mark shows that the tyre concerned has been initially approved in the Netherlands
(E4) pursuant to Regulation No. 117 and the 01 series of amendments under approval number 0167890.
This indicates that the approval is for S (rolling sound at Stage 1) and W (wet grip). The 02R1 preceded
by + indicates that it has had its approval extended under Regulation No. 117 and the 02 series of
amendments to rolling resistance at Stage 1 based on separate certificate(s).

1.2. Speed Measurements
The vehicle speed shall be measured with instruments with accuracy of ±1km/h or better
when the front end of the vehicle has reached Line PP' (Figure 1).
1.3. Temperature Measurements
Measurements of air as well as test surface temperature are mandatory.
The temperature measuring devices shall be accurate within ±1°C.
1.3.1. Air Temperature
The temperature sensor is to be positioned in an unobstructed location close to the
microphone in such a way that it is exposed to the airflow and protected from direct solar
radiation. The latter may be achieved by any shading screen or similar device. The sensor
should be positioned at a height of 1.2 ±0.1m above the test surface level, to minimize the
influence of the test surface thermal radiation at low airflows.
1.3.2. Test Surface Temperature
The temperature sensor is to be positioned in a location where the temperature measured is
representative of the temperature in the wheel tracks, without interfering with the sound
measurement.
If an instrument with a contact temperature sensor is used, heat-conductive paste shall be
applied between the surface and the sensor to ensure adequate thermal contact.
If a radiation thermometer (pyrometer) is used, the height should be chosen to ensure that a
measuring spot with a diameter of ≥0.1m is covered.
1.4. Wind Measurement
The device shall be capable of measuring the wind speed with a tolerance of ±1m/s. The
wind shall be measured at microphone height. The wind direction with reference to the
driving direction shall be recorded.

2.4.3. Wheelbase
The wheelbase between the two axles fitted with the test tyres shall for Class C1 be less
than 3.50m and for Class C2 and Class C3 Tyres be less than 5m.
2.4.4. Measures to Minimize Vehicle Influence on Sound Level Measurements
To ensure that tyre rolling sound is not significantly affected by the test vehicle design the
following requirements and recommendations are given.
2.4.4.1. Requirements:
(a)
(b)
(c)
(d)
(e)
Spray suppression flaps or other extra device to suppress spray shall not be fitted;
Addition or retention of elements in the immediate vicinity of the rims and tyres, which
may screen the emitted sound, is not permitted;
Wheel alignment (toe in, camber and caster) shall be in full accordance with the
vehicle manufacturer's recommendations;
Additional sound absorbing material may not be mounted in the wheel housings or
under the underbody;
Suspension shall be in such a condition that it does not result in an abnormal
reduction in ground clearance when the vehicle is loaded in accordance with the
testing requirement. If available, body level Regulation systems shall be adjusted to
give a ground clearance during testing which is normal for unladen condition.
2.4.4.2. Recommendations to Avoid Parasitic Noise:
(a)
(b)
(c)
(d)
Removal or modification on the vehicle that may contribute to the background noise
of the vehicle is recommended. Any removals or modifications shall be recorded in
the test report;
During testing it should be ascertained that brakes are not poorly released, causing
brake noise;
It should be ascertained that electric cooling fans are not operating;
Windows and sliding roof of the vehicle shall be closed during testing.

3. METHOD OF TESTING
3.1. General Conditions
For all measurements the vehicle shall be driven in a straight line over the measuring
section (AA' to BB') in such a way that the median longitudinal plane of the vehicle is as
close as possible to the Line CC'.
When the front end of the test vehicle has reached the Line AA' the vehicle driver shall have
put the gear selector on neutral position and switched off the engine. If abnormal noise
(e.g. ventilator, self-ignition) is emitted by the test vehicle during the measurement, the test
shall be disregarded.
3.2. Nature and Number of Measurements
The maximum sound level expressed in A-weighted decibels (dB(A)) shall be measured to
the first decimal place as the vehicle is coasting between Lines AA' and BB' (Figure 1 – front
end of the vehicle on Line AA', rear end of the vehicle on Line BB'). This value will constitute
the result of the measurement.
At least four measurements shall be made on each side of the test vehicle at test speeds
lower than the reference speed specified in Paragraph 4.1. below and at least four
measurements at test speeds higher than the reference speed. The speeds shall be
approximately equally spaced over the speed range specified in Paragraph 3.3. below.
3.3. Test Speed Range
The test vehicle speeds shall be within the range:
(a)
(b)
From 70 to 90km/h for Class C1 and Class C2 Tyres;
From 60 to 80km/h for Class C3 Tyres.
4. INTERPRETATION OF RESULTS
The measurement shall be invalid if an abnormal discrepancy between the values is
recorded (see Paragraph 2.3.2. of this Annex).
4.1. Determination of Test Result
Reference speed V used to determine the final result will be:
(a)
(b)
80km/h for Class C1 and Class C2 Tyres;
70km/h for Class C3 Tyres.

4.3. Temperature Correction
For Class C1 and Class C2 Tyres, the final result shall be normalized to a test surface
reference temperature ϑ by applying a temperature correction, according to the following:
Where:
L (ϑ ) = L (ϑ) + K(ϑ – ϑ)
ϑ
= the measured test surface temperature,
ϑ = 20°C,
For Class C1 Tyres, the coefficient K is: -0.03dB(A)/°C, when ϑ > ϑ and: -0.06dB(A)/°C
when ϑ < ϑ .
For Class C2 Tyres, the coefficient K is -0.02dB(A)/°C
If the measured test surface temperature does not change more than 5°C within all
measurements necessary for the determination of the sound level of one set of tyres, the
temperature correction may be made only on the final reported tyre rolling sound level as
indicated above, utilizing the arithmetic mean value of the measured temperatures.
Otherwise each measured sound level L shall be corrected, utilizing the temperature at the
time of the sound recording.
There will be no temperature correction for Class C3 Tyres.
4.4. In order to take account of any measuring instrument inaccuracies, the results according to
Paragraph 4.3. shall be reduced by 1dB(A).
4.5.
The final result, the temperature corrected tyre rolling sound level L (ϑ
) in dB(A), shall be
rounded down to the nearest lower whole value.

APPENDIX 1
TEST REPORT
Part 1 − Report
1. Type approval authority or Technical Service: ...............................................................................
2. Name and address of applicant: ....................................................................................................
........................................................................................................................................................
3. Test report No.: ..............................................................................................................................
4. Manufacturer and Brand Name or Trade description: ...................................................................
5. Tyre Class (C1, C2 or C3): .............................................................................................................
6. Category of use: .............................................................................................................................
7. Sound level according to Paragraphs 4.4. and 4.5. of Annex 3: ........................................... dB(A)
at reference speed of 70/80km/h
8. Comments (if any): .........................................................................................................................
........................................................................................................................................................
9. Date: ...............................................................................................................................................
10. Signature: .......................................................................................................................................
Part 2 − Test Data
1. Date of test: ....................................................................................................................................
2. Test vehicle (Make, model, year, modifications, etc.): ...................................................................
........................................................................................................................................................
2.1. Test vehicle wheelbase: ........................................................................................................... mm
3. Location of test track: .....................................................................................................................
3.1. Date of track certification to ISO 10844:2014: ...............................................................................
3.2. Issued by: .......................................................................................................................................
3.3. Method of certification: ...................................................................................................................

ANNEX 4
SPECIFICATIONS FOR THE TEST SITE
1. INTRODUCTION
This Annex describes the specifications relating to the physical characteristics and the
laying of the test track. These specifications based on a special standard describe the
required physical characteristics as well as the test methods for these characteristics.
2. REQUIRED CHARACTERISTICS OF THE SURFACE
A surface is considered to conform to this standard provided that the texture and voids
content or sound absorption coefficient have been measured and found to fulfil all the
requirements of Paragraphs 2.1. to 2.4. below and provided that the design requirements
(Paragraph 3.2. below) have been met.
2.1. Residual Voids Content
The residual voids content (VC) of the test track paving mixture shall not exceed 8%. For
the measurement procedure, see Paragraph 4.1. of this Annex.
2.2. Sound Absorption Coefficient
If the surface fails to comply with the residual voids content requirement, the surface is
acceptable only if its sound absorption coefficient α ≤0.10. For the measurement procedure,
see Paragraph 4.2. below. The requirements of Paragraphs 2.1. and 2.2. are met also if
only sound absorption has been measured and found to be α ≤0.10.
Note: The most relevant characteristic is the sound absorption, although the residual voids
content is more familiar among road constructors. However, sound absorption
needs to be measured only if the surface fails to comply with the voids requirement.
This is motivated because the latter is connected with relatively large uncertainties
in terms of both measurements and relevance and some surfaces therefore
erroneously may be rejected when based only on the voids measurement.
2.3. Texture Depth
The texture depth (TD) measured according to the volumetric method (see Paragraph 4.3.
below) shall be:
2.4. Homogeneity of the Surface
TD ≥0.4mm
Every practical effort shall be taken to ensure that the surface is made to be as
homogeneous as possible within the test area. This includes the texture and voids content,
but it should also be observed that if the rolling process results in more effective rolling at
some places than others, the texture may be different and unevenness causing bumps may
also occur.

NOTE − There shall be no large acoustically reflective objects within this radius
Figure 1
Minimum Requirements for Test Surface Area The Shaded Part is called "Test Area"
3.2. Design and Preparation of the Surface
3.2.1. Basic Design Requirements
The test surface shall meet four design requirements:
3.2.1.1. It shall be a dense asphaltic concrete.
3.2.1.2. The maximum chipping size shall be 8mm (tolerances allow from 6.3mm to 10mm).
3.2.1.3. The thickness of the wearing course shall be ≥30mm.
3.2.1.4. The binder shall be a straight penetration grade bitumen without modification.

Figure 2
Grading Curve of the Aggregate in the Asphaltic Mix with Tolerances
In addition to the above, the following recommendations are given:
(a)
(b)
(c)
(d)
(e)
(f)
(g)
The sand fraction (0.063mm < square mesh sieve size <2mm) shall include no more
than 55% natural sand and at least 45% crushed sand;
The base and sub-base shall ensure a good stability and evenness, according to best
road construction practice;
The chippings shall be crushed (100% crushed faces) and of a material with a high
resistance to crushing;
The chippings used in the mix shall be washed;
No extra chippings shall be added onto the surface;
The binder hardness expressed as PEN value shall be 40 – 60, 60 – 80 or even
80 – 100 depending on the climatic conditions of the country. The rule is that as hard
a binder as possible shall be used, provided this is consistent with common practice;
The temperature of the mix before rolling shall be chosen so as to achieve by
subsequent rolling the required voids content. In order to increase the probability of
satisfying the specifications of Paragraphs 2.1. to 2.4. above, the compactness shall
be studied not only by an appropriate choice of mixing temperature, but also by an
appropriate number of passings and by the choice of compacting vehicle.

4.2. Sound Absorption Coefficient
The sound absorption coefficient (normal incidence) shall be measured by the impedance
tube method using the procedure specified in ISO 10534-1:1996 or ISO 10534-2:1998.
Regarding test specimens, the same requirements shall be followed as regarding the
residual voids content (see Paragraph 4.1. above). The sound absorption shall be measured
in the range between 400Hz and 800Hz and in the range between 800Hz and 1,600Hz (at
least at the centre frequencies of third octave bands) and the maximum values shall be
identified for both of these frequency ranges. Then these values, for all test cores, shall be
averaged to constitute the final result.
4.3. Volumetric Macro-texture Measurement
For the purpose of this standard, texture depth measurements shall be made on at least
10 positions evenly spaced along the wheel tracks of the test strip and the average value
taken to compare with the specified minimum texture depth. See Standard ISO 10844:1994
for description of the procedure.
5. STABILITY IN TIME AND MAINTENANCE
5.1. Age Influence
In common with any other surfaces, it is expected that the tyre rolling sound level measured
on the test surface may increase slightly during the first 6-12 months after construction.
The surface will achieve its required characteristics not earlier than four weeks after
construction. The influence of age on the noise from trucks is generally less than that from
cars.
The stability over time is determined mainly by the polishing and compaction by vehicles
driving on the surface. It shall be periodically checked as stated in Paragraph 2.5. above.
5.2. Maintenance of the Surface
Loose debris or dust, which could significantly reduce the effective texture depth shall be
removed from the surface. In countries with winter climates, salt is sometimes used for
de-icing. Salt may alter the surface temporarily or even permanently in such a way as to
increase noise and is therefore not recommended.
5.3. Repaving the Test Area
If it is necessary to repave the test track, it is usually unnecessary to repave more than the
test strip (of 3m width in Figure 1) where vehicles are driving, provided the test area outside
the strip met the requirement of residual voids content or sound absorption when it was
measured.

ANNEX 5
TEST PROCEDURES FOR MEASURING WET GRIP
PART A
C1 CATEGORY TYRES
1. REFERENCE STANDARDS
The following documents listed apply.
1.1. ASTM E 303-93 (Reapproved 2008), Standard Test Method for Measuring Surface
Frictional Properties Using the British Pendulum Tester.
1.2. ASTM E 501-08, Standard Specification for Standard Rib Tire for Pavement
Skid-Resistance Tests.
1.3. ASTM E 965-96 (Reapproved 2006), Standard Test Method for Measuring Pavement
Macrotexture Depth Using a Volumetric Technique.
1.4. ASTM E 1136-93 (Reapproved 2003), Standard Specification for a Radial Standard
Reference Test Tire P195/75R14.
1.5. ASTM F 2493-08, Standard Specification for a Radial Standard Reference Test Tire
P225/60R16.
2. DEFINITIONS
For the purposes of testing wet grip of C1 tyres:
2.1. "Test run" means a single pass of a loaded tyre over a given test track surface.
2.2. "Test tyre(s)" means a candidate tyre, a reference tyre or a control tyre or tyre set that is
used in a test run.
2.3. "Candidate tyre(s) (T)" means a tyre or a tyre set that is tested for the purpose of
calculating its wet grip index.
2.4. "Reference tyre(s) (R)" means a tyre or a tyre set that has the characteristics indicated in
the ASTM F 2493-08 and referred to as the Standard Reference Test Tyre.
2.5. "Control tyre(s) (C)" means an intermediate tyre or a set of intermediate tyres which is
used when the candidate tyre and the reference tyre cannot be directly compared on the
same vehicle.
2.6. "Braking force of a tyre" means the longitudinal force, expressed in newton, resulting
from braking torque application.
2.7. "Braking force coefficient of a tyre (BFC)" means the ratio of the braking force to the
vertical load.

3.2. Methods to measure the wetted frictional properties of the surface
3.2.1. British Pendulum Number (BPN) Method (a)
The British Pendulum Number method shall be as defined in ASTM E 303-93
(Reapproved in 2008).
Pad rubber component formulation and physical properties shall be as specified in
ASTM E 501-08.
The averaged British Pendulum Number (BPN) shall be between 42 and 60 BPN after
temperature correction as follows.
(BPN) shall be corrected by the wetted road surface temperature. Unless temperature
correction recommendations are indicated by the British pendulum manufacturer, the
following formula is used:
BPN = BPN (measured value) + temperature correction
temperature correction = -0.0018t + 0.34t - 6.1
where t is the wetted road surface temperature in degrees Celsius.
Effects of slider pad wear: the pad shall be removed for maximum wear when the wear on
the striking edge of the slider reaches 3.2mm in the plane of the slider or 1.6mm vertical to
it in accordance with Paragraph 5.2.2. and Figure 3 of ASTM E 303-93
(Reapproved 2008).
For the purpose of checking track surface BPN consistency for the measurement of wet
grip on an instrumented passenger car: the BPN values of the test track should not vary
over the entire stopping distance so as to decrease the dispersion of test results. The
wetted frictional properties of the surface shall be measured five times at each point of the
BPN measurement every 10m and the coefficient of variation of the averaged BPN shall
not exceed 10%.
3.2.2. ASTM E 1136 Standard Reference Test Tyre Method (b)
By derogation with Paragraph 2.4. above, this method uses the reference tyre that has the
characteristics indicated in the ASTM E 1136-93 (Reapproved 2003) and referred to as
SRTT14.
The average peak braking force coefficient (μ
65km/h.
The average peak braking force coefficient (μ
the wetted road surface temperature as follows:
) of the SRTT14 shall be 0.7 ± 0.1 at
) of the SRTT14 shall be corrected for
Peak braking force coefficient (μ ) = peak braking force coefficient (measured) +
temperature correction
Temperature correction = 0.0035 × (t - 20)
Where t is the wetted road surface temperature in degrees Celsius.

4.1.2.2. Measuring Equipment
The vehicle shall be fitted with a sensor suitable for measuring speed on a wet surface
and distance covered between two speeds.
To measure vehicle speed, a fifth wheel or non-contact speed-measuring system shall be
used.
4.1.3. Conditioning of the Test Track and Wetting Condition
The test track surface shall be watered at least half an hour prior to testing in order to
equalize the surface temperature and water temperature. External watering should be
supplied continuously throughout testing. For the whole testing area, the water depth shall
be 1.0 ± 0.5mm, measured from the peak of the pavement.
The test track should then be conditioned by conducting at least ten test runs with tyres
not involved in the test programme at 90km/h.
4.1.4. Tyres and Rims
4.1.4.1. Tyre Preparation and Break-in
4.1.4.2. Tyre Load
The test tyres shall be trimmed to remove all protuberances on the tread surface caused
by mould air vents or flashes at mould junctions.
Fit the test tyres on rims specified by a recognized tyre and rim standards organization as
listed in Appendix 4 to Annex 6 to this Regulation.
The static load on each axle tyre shall lie between 60% and 90% of the tested tyre load
capacity. Tyre loads on the same axle should not differ by more than 10%.
4.1.4.3. Tyre Inflation Pressure
On the front and rear axles, the inflation pressures shall be 220kPa (for standard- and
extra-load tyres). The tyre pressure should be checked just prior to testing at ambient
temperature and adjusted if required.

4.1.5.2.4. The test cycle is closed by three more valid measurements of the same set of reference
tyres as at the beginning of the test cycle.
Examples:
(a)
The run order for a test cycle of three sets of candidate tyres (T1 to T3) plus a set of
reference tyres (R) would be the following:
R-T1-T2-T3-R
(b)
The run order for a test cycle of five sets of candidate tyres (T1 to T5) plus a set of
reference tyres (R) would be the following:
R-T1-T2-T3-R-T4-T5-R
4.1.6. Processing of Measurement Results
4.1.6.1. Calculation of the Average Deceleration (AD)
The average deceleration (AD) is calculated for each valid test run in m/s as follows:
AD =
S
− S
2 d
where:
S
S
d
is the final speed in m/s; S = 20km/h = 5.556m/s
is the initial speed in m/s; S = 80km/h = 22.222m/s
is the distance covered between S and S in metre.
4.1.6.2. Validation of Results
The AD coefficient of variation is calculated as follows:
(Standard Deviation / Average) × 100.
For the reference tyres (R): If the AD coefficient of variation of any two consecutive groups
of three tests runs of the reference tyre set is higher than 3%, all data should be discarded
and the test repeated for all test tyres (the candidate tyres and the reference tyres).
For the candidate tyres (T): The AD coefficients of variation are calculated for each
candidate tyre set. If one coefficient of variation is higher than 3%, the data should be
discarded and the test repeated for that candidate tyre set.

4.1.6.5. Calculation of the Wet Grip Index of the Candidate Tyre
The wet grip index of the candidate tyre (G(T)) is calculated as follows:
where:
( T)
( R)
( R)
( R )

BFC
⎛ BFC ⎞⎤
G ( T)
= ⎢ × 125 + a × ( t − t ) + b × ⎜
− 1,0⎟⎥
× 10
⎢ BFC

BFC
⎟⎥


⎠⎦
t
t
BFC(R )
is the measured wet surface temperature in degree Celsius when the candidate
tyre (T) is tested
is the wet surface reference temperature condition, t = 20°C for normal tyres
and t = 10°C for snow tyres
is the braking force coefficient for the reference tyre in the reference conditions,
BFC(R ) = 0.68
a = -0.4232 and b = -8.297 for normal tyres, a = 0.7721 and b = 31.18 for snow tyres [a is
expressed as (1/°C)]
4.1.7. Wet grip performance comparison between a candidate tyre and a reference tyre using a
control tyre
4.1.7.1. General
Where the candidate tyre size is significantly different from that of the reference tyre, a
direct comparison on the same instrumented passenger car may not be possible. This
testing method uses an intermediate tyre, hereinafter called the control tyre as defined in
Paragraph 2.5. above.

4.2. Testing Method (b) Using a Trailer Towed by a Vehicle or a Tyre Test Vehicle
4.2.1. Principle
4.2.2. Equipment
The measurements are conducted on test tyres mounted on a trailer towed by a vehicle
(hereafter referred to as tow vehicle) or on a tyre test vehicle. The brake in the test
position is applied firmly until sufficient braking torque is generated to produce the
maximum braking force that will occur prior to wheel lockup at a test speed of 65km/h.
4.2.2.1. Tow Vehicle and Trailer or Tyre Test Vehicle
The tow vehicle or the tyre test vehicle shall have the capability of maintaining the
specified speed of 65 ± 2km/h even under the maximum braking forces.
The trailer or the tyre test vehicle shall be equipped with one place where the tyre can be
fitted for measurement purposes hereafter called 'test position' and the following
accessories:
(a)
(b)
(c)
Equipment to activate brakes in the test position;
A water tank to store sufficient water to supply the road surface wetting system,
unless external watering is used;
Recording equipment to record signals from transducers installed at the test position
and to monitor water application rate if the self-watering option is used.
The maximum variation of toe-settings and camber angle for the test position shall be
within ±0.5° with maximum vertical load. Suspension arms and bushings shall have
sufficient rigidity necessary to minimize free play and ensure compliance under application
of maximum braking forces. The suspension system shall provide adequate load-carrying
capacity and be of such a design as to isolate suspension resonance.
The test position shall be equipped with a typical or special automotive brake system
which can apply sufficient braking torque to produce the maximum value of braking test
wheel longitudinal force at the conditions specified.
The brake application system shall be able to control the time interval between initial brake
application and peak longitudinal force as specified in Section 4.2.7.1. below.
The trailer or the tyre test vehicle shall be designed to accommodate the range of
candidate tyre sizes to be tested.
The trailer or the tyre test vehicle shall have provisions for adjustment of vertical load as
specified in Section 4.2.5.2. below.

4.2.4. Wetting Conditions
The tow vehicle and trailer or the tyre test vehicle may be optionally equipped with a
pavement-wetting system, less the storage tank, which, in the case of the trailer, is
mounted on the tow vehicle. The water being applied to the pavement ahead of the test
tyres shall be supplied by a nozzle suitably designed to ensure that the water layer
encountered by the test tyre has a uniform cross section at the test speed with a minimum
splash and overspray.
The nozzle configuration and position shall ensure that the water jets are directed towards
the test tyre and pointed towards the pavement at an angle of 20° to 30°.
The water shall strike the pavement 250mm to 450mm ahead of the centre of tyre contact.
The nozzle shall be located 25mm above the pavement or at the minimum height required
to clear obstacles which the tester is expected to encounter, but in no case more than
100mm above the pavement.
The water layer shall be at least 25mm wider than the test tyre tread and applied so the
tyre is centrally located between the edges. Water delivery rate shall ensure a water depth
of 1.0 ± 0.5mm and shall be consistent throughout the test to within ±10%. The volume of
water per unit of wetted width shall be directly proportional to the test speed. The quantity
of water applied at 65km/h shall be 18l/s per metre of width of wetted surface in case of a
water depth of 1.0mm.
4.2.5. Tyres and Rims
4.2.5.1. Tyre Preparation and Break-in
4.2.5.2. Tyre Load
The test tyres shall be trimmed to remove all protuberances on the tread surface caused
by mould air vents or flashes at mould junctions.
The test tyre shall be mounted on the test rim declared by the tyre manufacturer.
A proper bead seat should be achieved 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 test tyres/rim assemblies shall be stored in a location for a minimum of two hours
such that they all have the same ambient temperature prior to testing. They should be
shielded from the sun to avoid excessive heating by solar radiation.
For tyre break-in, two braking runs shall be performed under the load, pressure and speed
as specified in Paragraphs 4.2.5.2, 4.2.5.3 and 4.2.7.1 respectively.
The test load on the test tyre is 75 ± 5% of the tyre load capacity.
4.2.5.3. Tyre Inflation Pressure
The test tyre cold inflation pressure shall be 180kPa for standard-load tyres. For
extra-load tyres, the cold inflation pressure shall be 220kPa.
The tyre pressure should be checked just prior to testing at ambient temperature and
adjusted if required.

4.2.7.2.4. The test cycle is closed by six more valid measurements of the same reference tyre as at
the beginning of the test cycle.
Examples:
(a)
The run order for a test cycle of three candidate tyres (T1 to T3) plus the reference
tyre (R) would be the following:
R-T1-T2-T3-R
(b)
The run order for a test cycle of five candidate tyres (T1 to T5) plus the reference
tyre R would be the following:
R-T1-T2-T3-R-T4-T5-R
4.2.8. Processing of Measurement Results
4.2.8.1. Calculation of the Peak Braking Force Coefficient
The tyre peak braking force coefficient (μ ) is the highest value of μ(t) before lockup
occurs calculated as follows for each test run. Analogue signals should be filtered to
remove noise. Digitally recorded signals must be filtered using a moving average
technique.
()
μ t =
f h
f v
() t
() t
where:
μ(t)
is the dynamic tyre braking force coefficient in real time;
fh(t) is the dynamic braking force in real time, in N;
fv(t) is the dynamic vertical load in real time, in N.
4.2.8.2. Validation of Results
The μ coefficient of variation is calculated as follows:
(Standard Deviation / Average) × 100
For the reference tyre (R): If the coefficient of variation of the peak braking force coefficient
(μ ) of the reference tyre is higher than 5%, all data should be discarded and the test
repeated for all test tyres (the candidate tyre(s) and the reference tyre).
For the candidate tyre(s) (T): The coefficient of variation of the peak braking force
coefficient (μ ) is calculated for each candidate tyre. If one coefficient of variation is
higher than 5%, the data should be discarded and the test repeated for this candidate tyre.

4.2.8.5. Calculation of the Wet Grip Index of the Candidate Tyre
The wet grip index of the candidate tyre (G(T)) is calculated as follows:
( T)
( R)
( R)
( R )


G ( T)

μ


125 a ( t t ) b
⎜ μ
1,0

=
× + × − + ×
⎥ × 10



⎟⎥
μ


μ


where:
t
t
t =
is the measured wet surface temperature in degree Celsius when the
candidate tyre (T) is tested
is the wet surface reference temperature condition,
20°C for normal tyres and t = 10°C for snow tyres
μ (R ) = 0.85 is the peak braking force coefficient for the reference tyre in the
reference conditions
a =
-0.4232 and b = -8.297 for normal tyres, a = 0.7721 and b = 31.18 for
snow tyres [a is expressed as (1/°C)]

1.1.2. British Pendulum Number (BPN) method
The averaged British Pendulum Number (BPN) British Pendulum Tester method as
specified in ASTM E 303-93 (reapproved 2008) using the Pad as specified in
ASTM E 501-08 shall be (50 ± 10) BPN after temperature correction.
BPN shall be corrected by the wetted road surface temperature. Unless temperature
correction recommendations are indicated by the British pendulum manufacturer the
following formula can be used:
BPN = BPN (measured value) – (0.0018 · t²) + 0.34 · t - 6.1
Where: "t" is the wetted road surface temperature in degrees Celsius.
Effects of slider pad wear: the pad should be removed for maximum wear when the wear
on the striking edge of the slider reaches 3.2mm in the plane of the slider or 1.6mm
vertical to it.
Check the test track testing surface BPN consistency for the measurement of wet grip on a
standard vehicle.
In the lanes of the track to be used during the wet grip tests, the BPN shall be measured at
intervals of 10m along the length of the lanes. The BPN shall be measured 5 times at each
point and the coefficient of variation of the BPN averages shall not exceed 10%.
1.1.3. The Type Approval Authority shall satisfy itself of the characteristics of the track on the
basis of evidence produced in test reports.
1.2. The surface may be wetted from the track-side or by a wetting system incorporated into
the test vehicle or the trailer.
If a track-side system is used, the test surface shall be wetted for at least half an hour prior
to testing in order to equalize the surface temperature and water temperature. It is
recommended that track-side wetting be continuously applied throughout testing.
The water depth shall be between 0.5 and 2.0mm.
1.3. The wind conditions shall not interfere with wetting of the surface (windshields are
permitted).
The ambient and the wetted surface temperature shall be between 5°C and 35°C and shall
not vary during the test by more than 10°C.

2.1.1.3. Be capable of maintaining longitudinal alignment (toe) and camber of the test wheel and
tyre assembly throughout the test within ±0.5° of the static figures achieved at the test tyre
loaded condition;
2.1.1.4. In the case a track wetting system is incorporated:
The system shall be able to deliver the water such that the tyre and track surface in front
of the tyre are wetted before the start of braking and throughout the duration of the test.
The apparatus may be optionally equipped with a pavement-wetting system, less the
storage tank, which, in the case of the trailer, is mounted on the tow vehicle. The water
being applied to the pavement ahead of the test tyres shall be supplied by a nozzle
suitably designed to ensure that the water layer encountered by the test tyre has a uniform
cross section at the test speed with a minimum splash and overspray.
The nozzle configuration and position shall ensure that the water jets shall be directed
toward the test tyre and pointed toward the pavement at an angle of 15 to 30°. The water
shall strike the pavement 0.25 to 0.5m ahead of the centre of tyre contact. The nozzle
shall be located 100mm above the pavement or the minimum height required to clear
obstacles which the tester is expected to encounter, but in no case more than 200mm
above the pavement. The water layer shall be at least 25mm wider than the test tyre tread
and applied so the tyre is centrally located between the edges. The volume of water per
unit of wetted width shall be directly proportional to the test speed. The quantity of water
applied at 50km/h shall be 14l/s per meter of the width of the wetted surface. The nominal
values of rate of water application shall be maintained within ±10%.
2.1.2. Test Procedure
2.1.2.1. Fit the test tyres on rims specified by a recognized tyre and rim standards organization as
listed in Appendix 4 to Annex 6 to this Regulation. 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.
Check the test tyres for the specified inflation pressure at ambient temperature (cold), just
prior to testing. For the purpose of this standard the testing tyre cold inflation pressure P
shall be calculated as follows:
P
= P
⎛ Q
× ⎜
⎝ Q



Where:
P =
Inflation pressure marked on the sidewall. If P is not marked on the sidewall refer to
the specified pressure in applicable tyre standards manuals corresponding to
maximum load capacity for single applications
Q = The static test load of the tyre
Q = The maximum mass associated with the load capacity index of the tyre
2.1.2.2. For tyre break-in, two braking runs are performed. The tyre shall be conditioned for a
minimum of two hours adjacent to the test track such that it is stabilized at the ambient
temperature of the test track area. The tyre(s) shall not be exposed to direct sunshine
during conditioning.

2.1.2.12.
Calculate the peak braking force coefficient, μ
, for each test using the following
equation:
Where:
( t )
( t )
f
μ ( t ) =
(1)
f
μ(t) =
dynamic tyre braking force coefficient in real time,
f (t) = dynamic braking force in real time, N,
f (t) =
dynamic vertical load in real time, N
Using equation (1) for dynamic tyre braking force coefficient, calculate the peak tyre
braking force coefficient, μ , by determining the highest value of μ(t) before lockup
occurs. Analogic signals should be filtered to remove noise. Digitally recorded signals may
be filtered using a moving average technique.
Calculate the average values of peak-braking coefficient (μ ) by averaging four or
more valid repeated runs for each set of test and reference tyres for each test condition
provided that the tests are completed within the same day.
2.1.2.13. Validation of Results
For the reference tyre:
If the coefficient of variation of the peak braking coefficient, which is calculated by
"standard deviation/average x 100" of the reference tyre is higher than 5%, discard all data
and repeat the test for this reference tyre.
For the candidate tyres:
The coefficients of variation (standard deviation/average x 100) are calculated for all the
candidate tyres. If one coefficient of variation is greater than 5%, discard the data for this
candidate tyre and repeat the test.
If R1 is the average of the peak braking coefficient in the first test of the reference tyre, R2
is the average of the peak braking coefficient in the second test of the reference tyre, the
following operations are performed, according to the following table:
If the number of sets of candidate
tyres between two successive
runs of the reference tyre is:
and the set of candidate
tyres to be qualified is:
then "Ra" is calculated by
applying the following:
1 � R1 – T1 – R2 T1 Ra = 1/2 (R1 + R2)
2 � R1 – T1 – T2 – R2 T1
T2
3 � R1 – T1 – T2 – T3 – R2 T1
T2
T3
Ra = 2/3 R1 + 1/3 R2
Ra = 1/3 R1 + 2/3 R2
Ra = 3/4 R1 + 1/4 R2
Ra = 1/2 (R1 + R2)
Ra = 1/4 R1 + 3/4 R2

2.2.2.2. Vehicle Equipment
The rear axle may be indifferently fitted with 2 or 4 tyres.
For the reference tyre testing, both axles are fitted with reference tyres. (A total of 4 or 6
reference tyres depending on the choice above mentioned).
For the candidate tyre testing, 3 fitting configurations are possible:
(a)
(b)
(c)
Configuration "Configuration 1": Candidate tyres on front and rear axles: it is the
standard configuration that should be used every time it is possible.
Configuration "Configuration 2": Candidate tyres on front axle and reference tyre or
control tyre on rear axle: allowed in such cases where fitting the candidate tyre on
the rear position is not possible.
Configuration "Configuration 3": Candidate tyres on rear axle and reference tyre or
control tyre on front axle: permitted in such cases where fitting the candidate tyre on
the front position is not possible.
2.2.2.3. Tyre Inflation Pressure
(a)
For a vertical load higher or equal to 75% of the load capacity of the tyre, the test
inflation pressure "P " shall be calculated as follows:
P = P · (Q /Q )
P = Inflation pressure marked on the sidewall. If P is not marked on the sidewall
refer to the specified pressure in applicable tyre standards manuals
corresponding to maximum load capacity for single applications
Q = static test load of the tyre
Q = maximum mass associated with the load capacity index of the tyre
(b)
For a vertical load lower than 75% of the load capacity of the tire, the test inflation
pressure P shall be calculated as follows:
P = P · (0.75) = (0.7) · P
P = Inflation pressure marked on the sidewall.
If P is not marked on the sidewall refer to the specified pressure in applicable tyre
standard manuals corresponding to maximum load capacity for single applications.
Check the tyre pressure just prior to testing at ambient temperature.

2.2.2.6.2. According to the type of transmission, two cases are possible:
(a)
Manual transmission
As soon as the driver is in the measuring zone and having reached 65 ± 2km/h, the
clutch is released and the brake pedal depressed sharply, holding it down as long
as necessary to perform the measurement.
(b)
Automatic transmission
As soon as the driver is in the measuring zone and having reached 65 ± 2km/h,
select neutral gear and then the brake pedal is depressed sharply, holding it down
as long as necessary to perform the measurement.
Automatic activation of the brakes can be performed by means of a detection system
made of two parts, one indexed to the track and one embarked on the vehicle. In that case
braking is made more rigorously at the same portion of the track.
If any of the above-mentioned conditions are not met when a measurement is made
(speed tolerance, braking time, etc.), the measurement is discarded and a new
measurement is made.
2.2.2.6.3. Test Running Order
Examples:
The run order for a test of 3 sets of candidate tyres (T1 to T3) plus a reference Tyre R
would be:
R – T1 – T2 – T3 – R
The run order for a test of 5 sets of tyres (T1 to T5) plus a reference tyre R would be:
R – T1 – T2 - T3 - R -T4 - T5 – R
2.2.2.6.4. The direction of the test shall be the same for each set of tests and shall be the same for
the candidate test tyre as that used for the SRTT with which its performance is to be
compared.
2.2.2.6.5. For each test and for new tires, the first two braking measurements are discarded.
2.2.2.6.6. After at least 3 valid measurements have been made in the same direction, the reference
tyres are replaced by a set of the candidate tyres (one of the 3 configurations presented in
Paragraph 2.2.2.2.) and at least 6 valid measurements shall be performed.
2.2.2.6.7. A maximum of three sets of candidate tyres can be tested before the reference tyre is
re-tested.

2.2.2.7.3. Calculation of the "average AD"
If R1 is the average of the AD values in the first test of the reference tyre and R2 is the
average of the AD values in the second test of the reference tyre, the following operations
are performed, according to Table 1.
Ra is the adjusted average AD of the reference tyre.
Number of sets of candidate tyres
between two successive runs of
the reference tyre
Table 1
Set of candidate tyres to
be qualified
1 R1 – T1 – R2 T1 Ra = 1/2 (R1 + R2)
2 R1 – T1 – T2 – R2 T1
T2
3 R1 – T1 – T2 – T3 – R2 T1
T2
T3
2.2.2.7.4. Calculation of Braking Force Coefficient, BFC
BFC(R) and BFC(T) are calculated according to Table 2:
Tyre type
Reference tyre
Candidate tyre
Table 2
g is the acceleration due to gravity (rounded to 9.81 m·s ).
Ra
Ra = 2/3 R1 + 1/3 R2
Ra = 1/3 R1 + 2/3 R2
Ra = 3/4 R1 + 1/4 R2
Ra = 1/2 (R1 + R2)
Ra = 1/4 R1 + 3/4 R2
Braking force coefficient is
BFC(R) = Ra/g
BFC(T) = Ta/g
Ta (a = 1, 2, etc.) is the average of the AD values for a test of a candidate tyre.

Figure 1
Nomenclature Explanation Related to Grip Index of the Tyre
2.2.2.8. Wet grip performance comparison between a candidate tyre and a reference tyre using a
control tyre
When the candidate tyre size is significantly different from the reference tyre, a direct
comparison on the same vehicle may be not possible. This approach uses an intermediate
tyre, hereinafter called the control tyre.
2.2.2.8.1. The principle lies upon the use of a control tyre and 2 different vehicles for assessing a
candidate tyre in comparison with a reference tyre.
One vehicle can fit the reference tyre and the control tyre, the other the control tyre and
the candidate tyre. All conditions are in conformity with Paragraphs 2.2.1.2. to 2.2.2.5.
above.
2.2.2.8.2. The first assessment is a comparison between the control tyre and the reference tyre. The
result (Wet Grip Index 1) is the relative efficiency of the control tyre compared to the
reference tyre.
2.2.2.8.3. The second assessment is a comparison between the candidate tyre and the control tyre.
The result (Wet Grip Index 2) is the relative efficiency of the candidate tyre compared to
the control tyre.
The second assessment is done on the same track as the first one and within one week
maximum. The wetted surface temperature shall be in the range of ±5°C of the
temperature of the first assessment. The control tyre set (4 or 6 tyres) is physically the
same set as the set used for the first assessment.

ANNEX 5 – APPENDIX
TEST REPORTS EXAMPLES OF WET GRIP INDEX
Example 1
Test Report of Wet Grip Index Using Trailer Method
Test report number:
Type of road surface:
μ peak (SRTT14 E1136):
Speed (km/h):
Test date:
Texture depth (mm):
or BPN:
Water depth (mm):
No.
1
2
3
4
5
6
7
8
9
10
Size
Service description
Tyre identification
Rim
Pattern
Load (N)
Pressure (kPa)
μpeak
1
2
3
4
5
6
7
8
Average
Standard deviation σ
(σ/average) ≤5%
Ra, Adjusted
Wet grip index
Surface temp. (°C)
Ambient temp. (°C)
Remarks

ANNEX 6
TEST PROCEDURE FOR MEASURING ROLLING RESISTANCE
1. TEST METHODS
The alternative measurement methods listed below are given in this Regulation. The choice of
an individual method is left to the tester. For each method, the test measurements shall be
converted to a force acting at the tyre/drum interface. The measured parameters are:
a) In the force method: the reaction force measured or converted at the tyre spindle ;
b) In the torque method: the torque input measured at the test drum ;
c) In the deceleration method: the measurement of deceleration of the test drum and tyre
assembly ;
d) In the power method: the measurement of the power input to the test drum .
2. TEST EQUIPMENT
2.1. Drum Specifications
2.1.1. Diameter
2.1.2. Surface
2.1.3. Width
The test dynamometer shall have a cylindrical flywheel (drum) with a diameter of at least 1.7m.
The F and C values shall be expressed relative to a drum diameter of 2.0m. If drum diameter
different than 2.0m is used, a correlation adjustment shall be made following the method in
Paragraph 6.3. of this Annex.
The surface of the drum shall be smooth steel. Alternatively, in order to improve skim test
reading accuracy, a textured surface may also be used, which should be kept clean.
The F and C values shall be expressed relative to the "smooth" drum surface. If a textured
drum surface is used, see Appendix 1, Paragraph 7.
The width of the drum test surface shall exceed the width of the test tyre contact patch.

Table 1
Test Speeds (in km/h)
Tyre Class C1 C2 and C3 C3
Load Index
All
LI ≤ 121
LI > 121
Speed Symbol
All
All
J 100km/h and lower or K 110km/h and higher
tyres not marked with
speed symbol
Speed
80
80
60
80
3.3. Test Load
The standard test load shall be computed from the values shown in Table 2 and shall be kept
within the tolerance specified in Appendix 1.
3.4. Test Inflation Pressure
The inflation pressure shall be in accordance with that shown in Table 2 and shall be capped
with the accuracy specified in Paragraph 4. of Appendix 1 to this Annex.
Table 2
Test Loads and Inflation Pressures
Tyre Class C1 C2, C3
Standard Load
Reinforced or
Extra Load
Load- % of maximum
load capacity
80
80
85
(% of single load)
Inflation pressure kPa
210
250 Corresponding to maximum load
capacity for single application
Note: The inflation pressure shall be capped with the accuracy specified in Paragraph 4 of
Appendix 1 to this Annex.

4.5.
Measurement and Recording
The following shall be measured and recorded (see Figure 1):
(a)
Test speed U ;
(b)
Load on the tyre normal to the drum surface L ;
(c)
(d)
The initial test inflation pressure as defined in Paragraph 3.3. above;
The coefficient of rolling resistance measured C , and its corrected value C , at 25°C and
for a drum diameter of 2m;
(e) The distance from the tyre axis to the drum outer surface under steady state r ,;
(f) Ambient temperature t ;
(g) Test drum radius R;
(h)
(i)
(j)
Test method chosen;
Test rim (size and material);
Tyre size, manufacturer, type, identity number (if one exists), speed symbol, load index,
DOT number (Department of Transportation).
Figure 1
All the mechanical quantities (forces, torques) will be orientated in accordance with the axis
systems specified in ISO 8855:1991.
The directional tyres shall be run in their specified rotation sense.

5. DATA INTERPRETATION
5.1. Determination of Parasitic Losses
5.1.1. General
The laboratory shall perform the measurements described in Paragraph 4.6.1. above for the
force, torque and power methods or those described in Paragraph 4.6.2. for the deceleration
method, in order to determine precisely in the test conditions (load, speed, temperature) the
tyre spindle friction, the tyre and wheel aerodynamic losses, the drum (and as appropriate,
engine and/or clutch) bearing friction, and the drum aerodynamic losses.
The parasitic losses related to the tyre/drum interface F expressed in newton shall be
calculated from the force F torque, power or the deceleration, as shown in Paragraphs 5.1.2. to
5.1.5. below.
5.1.2. Force Method at Tyre Spindle
Calculate: F = F (1 + r /R)
Where:
F
r
R
is the tyre spindle force in newton (see Paragraph 4.6.1. above),
is the distance from the tyre axis to the drum outer surface under steady state conditions,
in metre,
is the test drum radius, in metres.
5.1.3. Torque Method at Drum Axis
Calculate: F = T /R
Where:
T is the input torque in newton metre, as determined in Paragraph 4.6.1,
R
is the test drum radius, in metres.
5.1.4. Power Method at Drum Axis
Calculate:
F
3.6V × A
=
U
Where:
V
A
U
is the electrical potential applied to the machine drive, in volt,
is the electric current drawn by the machine drive, in ampere,
is the test drum speed, in kilometre per hour.

5.2. Rolling Resistance Calculation
5.2.1. General
The rolling resistance F , expressed in newton, is calculated using the values obtained by
testing the tyre to the conditions specified in this international standard and by subtracting the
appropriate parasitic losses F , obtained according to Paragraph 5.1. above.
5.2.2. Force Method at Tyre Spindle
The rolling resistance F , in newton, is calculated using the equation
Where:
F = F [1 + (r /R)] – F
F
F
r
R
is the tyre spindle force in newton,
represents the parasitic losses as calculated in Paragraph 5.1.2. above,
is the distance from the tyre axis to the drum outer surface under steady-state
conditions, in metre,
is the test drum radius, in metre.
5.2.3. Torque Method at Drum Axis
The rolling resistance F , in newton, is calculated with the equation
F
=
T
R
− F
Where:
T
F
R
is the input torque, in newton metre,
represents the parasitic losses as calculated in Paragraph 5.1.3. above,
is the test drum radius, in metre.

or
F
=
I
R
j
+
RI
R
j
− F
Where:
I
R
F
J
I
R
F
is the test drum inertia in rotation, in kilogram metre squared,
is the test drum surface radius, in metres,
represents the parasitic losses as calculated in Paragraph 5.1.5. above,
is the deceleration of the test drum, in radians per second squared,
is the spindle, tyre and wheel inertia in rotation, in kilogram metre squared,
is the tyre rolling radius, in metre,
is the rolling resistance, in newton.
6. DATA ANALYSIS
6.1. Rolling Resistance Coefficient
The rolling resistance coefficient C is calculated by dividing the rolling resistance by the load
on the tyre:
Where:
F
C =
L
F
is the rolling resistance, in newton,
L is the test load, in kN.

6.4. Measurement Result
Where n measurements are greater than 1, if required by Paragraph 4.6. above, the
measurement result shall be the average of the C values obtained for the n measurements,
after the corrections described in Paragraphs 6.2. and 6.3. above have been made.
6.5. The laboratory shall ensure that, based on a minimum of three measurements, the machine
maintains the following values of σ , as measured on a single tyre:
σ ≤ 0.075N/kN for tyres of Classes C1 and C2
σ ≤ 0.06N/kN for tyres of Class C3
If the above requirement for σ is not met, the following formula shall be applied to determine
the minimum number of measurements n (rounded to the immediate superior integer value)
that are required by the machine to qualify for conformance with this Regulation.
Where:
n = (σ / x)²
x = 0.075N/kN for tyres of Classes C1 and C2
x = 0.06N/kN for tyres of Class C3
If a tyre needs to be measured several times, the tyre/wheel assembly shall be removed from
the machine between the successive measurements.
If the removal/refitting operation duration is less than 10min, the warm-up durations indicated in
Paragraph 4.3. may be reduced to:
(a) 10mins for tyres of Class C1;
(b) 20mins for tyres of Class C2;
(c) 30mins for tyres of Class C3.
6.6. Monitoring of the laboratory control tyre shall be carried out at intervals no greater than one
month. Monitoring shall include a minimum of 3 separate measurements taken during this one
month period. The average of the 3 measurements taken during a given one-month period
shall be evaluated for drift from one monthly evaluation to another.

3.2. Tyre Alignment
3.2.1. Camber Angle
The plane of the wheel shall be perpendicular to the test surface within 2mrad for all methods.
3.2.2. Slip Angle
The plane of the tyre shall be parallel to the direction of the test surface motion within 1mrad for
all methods.
4. CONTROL ACCURACY
Test conditions shall be maintained at their specified values, independent of perturbations
induced by the tyre and rim non-uniformity, such that the overall variability of the rolling
resistance measurement is minimized. In order to meet this requirement, the average value of
measurements taken during the rolling resistance data collection period shall be within the
accuracies stated as follows:
(a)
Tyre loading:
(i)
(ii)
For LI ≤ 121 ±20N or ±0.5%, whichever is greater;
For LI > 121 ±45N or ±0.5% whichever is greater;
(b)
(c)
Cold inflation pressure: ±3kPa;
Surface speed:
(i)
(ii)
±0.2km/h for the power, torque and deceleration methods;
±0.5km/h for the force method;
(d)
Time:
(i)
(ii)
±0.02 s for the time increments specified in Annex 6, Paragraph 3.5.(b) for the
data acquisition in the deceleration method in ∆ω/∆t form;
±0.2% for the time increments specified in Annex 6, Paragraph 3.5.(a) for the data
acquisition in the deceleration method in dω/dt form;
(iii) ±5% for the other time durations specified in Annex 6.

7. TEST SURFACE ROUGHNESS
The roughness, measured laterally, of the smooth steel drum surface shall have a maximum
centreline average height value of 6.3µm.
Note: In cases where a textured drum surface is used instead of a smooth steel surface, this
fact is noted in the test report. The surface texture shall then be 180µm deep (80 grit)
and the laboratory is responsible for maintaining the surface roughness characteristics.
No specific correction factor is recommended for cases where a textured drum surface
is used.

Table 1
Coefficients for Determining Measuring Rim Width
Tyre Structure Code Type of rim Nominal aspect ratio H/S
Measuring rim/ section
ratio K
B, D, R
5° tapered
100 to 75
0.70
70 and 65
0.75
60
0.75
55
0.80
50
0.80
45
0.85
40
0.90
15° tapered
(drop-centre)
90 to 65
0.75
60
0.80
55
0.80
50
0.80
45
0.85
40
0.85
Note: Other factors may be established for new tyre concepts (structures).

4.6.
Test rim width and material: ..............................................................................................................
4.7.
Ambient temperature: .................................................................................................................. °C
4.8.
Skim test load (except deceleration method): .............................................................................. N
5.
Rolling resistance coefficient: ...........................................................................................................
5.1.
Initial value (or average in the case of more than 1): .............................................................. N/kN
5.2.
Temperature corrected N/kN: ...........................................................................................................
5.3.
Temperature and drum diameter corrected: ............................................................................ N/kN

APPENDIX 5
Deceleration method: Measurements and data processing for deceleration value obtaining in differential
form dω/dt.
1. Record dependency "distance-time" of rotating body decelerated from peripheral with a speed
range such as 82 to 78km/h or 62 to 58km/h dependent on tyre class (Annex 6, Paragraph 3.2.,
Table 1) in a discrete form (Figure 1) for a rotating body:
z=f(t )
Where:
z
t
is a number of body revolutions during deceleration;
is end time of revolution number z in seconds recorded with 6 digits after zero.
Figure 1
Note 1: The lower speed of the recording range may be reduced down to 60km/h when test
speed is 80km/h and 40km/h when the test speed is 60km/h.
2. Approximate recorded dependency by continuous, monotonic, differentiable function:
2.1. Choose the value nearest to the maximum of z dividable by 4 and divide it into 4 equal parts with
bounds: 0, z (t ), z (t ), z (t ), z (t ).

4. Estimate the quality of approximation of measured data and its accuracy by parameters:
4.1. Standard deviation in percentages:
1
σ = ∑
n − 1
[1 −
( t)
z
z
]
× 100%
4.2. Coefficient of Determination
R
= 1−
∑ [ z − z()
t ]

[ z − z]
Where:
1
z = ∑
n
1
=
n
( 1+
2 + ... + n)
1+
n
=
2
Note 3: The above calculations for this variant of the deceleration method for tyre rolling
resistance measurement can be executed by the computer program "Deceleration
Calculator" downloadable from the WP.29 website as well as any software which
allows the calculation of nonlinear regression

3. BRAKING ON SNOW METHOD FOR CLASS C1 AND C2 TYRES
3.1. General Conditions
3.1.1. Test Course
3.1.2. Vehicle
3.1.3. Tyres
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 3cm thick and a
surface layer of medium packed and prepared snow about 2cm thick.
The air temperature, measured about 1m above the ground, shall be between -2°C and
-15°C; the snow temperature, measured at a depth of about 1cm, 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 with a CTI penetrometer shall be between
75 and 85.
The test shall be conducted with a standard production vehicle in good running order and
equipped with an ABS system.
The vehicle used shall be such that the loads on each wheel are appropriate to the tyres
being tested. Several different tyre sizes can be tested on the same vehicle.
The tyres should be "broken-in" prior to testing to remove spew, compound nodules or flashes
resulting from moulding process. The tyre surface in contact with snow shall be cleaned
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 control vs. reference on another
vehicle, then test candidate vs. control on the vehicle.
3.1.4. Load and Pressure
3.1.4.1. For C1 tyres, 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.
The cold inflation pressure shall be 240kPa.

3.2. Testing Sequences
3.2.1. For every candidate tyre and the standard reference tyre, ABS-braking test runs shall be
repeated a minimum of 6 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.
Required sequence:
6 repeats SRTT, then shift aside to test next tyre on fresh surface
6 repeats Candidate 1, then shift aside
6 repeats Candidate 2, then shift aside
6 repeats SRTT, then shift aside
3.2.2. Order of Testing
If only one candidate tyre is to be evaluated, the order of testing shall be:
Where:
R1 – T – R2
R1
is the initial test of the SRTT, R2 is the repeat test of the SRTT and T is the test of the
candidate tyre to be evaluated.
A maximum of two candidate tyres may be tested before repeating the SRTT test, for
example:
R1 – T1 – T2 – R2.
3.2.3. The comparative tests of SRTT and candidate tyres shall be repeated on two different days.
3.3. Test Procedure
3.3.1. Drive the vehicle at a speed not lower than 28km/h.
3.3.2. 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 8km/h.
3.3.3. The mean fully developed deceleration between 25km/h and 10km/h shall be computed from
time, distance, speed, or acceleration measurements.

3.4.3. 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.
3.4.3.1. The snow grip index 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 Paragraphs 3.1.
to 3.4.2. above.
The snow grip index of the candidate tyre relative to the SRTT shall be the product of the two
resulting snow grip indices that is SG1 × SG2.
3.4.3.2. The ambient conditions shall be comparable. All tests shall be completed within the same
day.
3.4.3.3. 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.
3.4.3.4. Control tyres that have been used for testing shall subsequently be stored under the same
conditions as required for the SRTT.
3.4.3.5. 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. ACCELERATION METHOD FOR CLASS C3 TYRES
4.1. According to the definition of C3 tyres reported into Paragraph 2.4.3. above, the additional
classification for the purpose of this test method only applies:
(a) C3 Narrow (C3N), when the C3 tyre Nominal Section Width is lower than 285mm
(b) C3Wide (C3W), when the C3 tyre Nominal Section Width is greater or equal to 285mm
4.2. Methods for Measuring Snow Grip Index
Snow performance is based on a test method by which the average acceleration in an
acceleration test, of a candidate tyre is compared to that of a standard reference tyre.
The relative performance shall be indicated by a Snow Grip Index (SG).
When tested in accordance with the acceleration test in Paragraph 4.7. below, the average
acceleration of a candidate snow tyre shall be at least 1.25 compared to one of the two
equivalent SRTTs – ASTM F 2870 and ASTM F 2871.

4.4. General Conditions
4.4.1. Test Course
The test shall be done on a flat test surface of sufficient length and width, with a maximum 2%
gradient, covered with packed snow.
4.4.1.1. The snow surface shall be composed of a hard packed snow base at least 3cm thick and a
surface layer of medium packed and prepared snow about 2cm thick.
4.4.1.2. The snow compaction index measured with a CTI penetrometer shall be between 80 and 90.
Refer to the appendix of ASTM F1805 for additional details on measuring method.
4.4.1.3. The air temperature, measured about 1m above the ground, shall be between -2°C and
-15°C; the snow temperature, measured at a depth of about 1cm, shall be between -4°C and
-15°C.
Air temperature shall not vary more than 10°C during the test.
4.5. Tyres Preparation and Break-in
4.5.1. Fit the test tyres on rims as per ISO 4209-1 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.
4.5.2. The tyres should be "broken-in" prior to testing to remove spew, compound nodules or flashes
resulting from moulding process.
4.5.3. Tyres shall be conditioned at the outdoor ambient temperature at least two hours before their
mounting for tests.
They should be placed such that they all have the same ambient temperature prior to testing
and be shielded from the sun to avoid excessive heating by solar radiation.
The tyre surface in contact with snow shall be cleaned before performing a test.
Tyre pressures shall then be adjusted to the values specified for the test.

4.7.2.1.1. In the particular case where a standard commercial vehicle equipped with a traction control
system is not available, a vehicle without Traction Control/ASR/TCS is permitted provided the
vehicle is fitted with a system to display the percentage slip as stated in Paragraph 4.3.4. of
this Annex and a mandatory differential lock on the driven axle used in accordance with the
operating procedure 4.7.5.2.1. below. If a differential lock is available it shall be used; if the
differential lock, however, is not available, the average slip ratio should be measured on the
left and right driven wheel.
4.7.2.2. The permitted modifications are:
(a) Those allowing to increase the number of tyre sizes capable to be mounted on the
vehicle;
(b)
Those permitting to install an automatic activation of the acceleration and the
measurements.
Any other modification of the acceleration system is prohibited.
4.7.3. Vehicle Fitting
The rear driven axle may be indifferently fitted with 2 or 4 test tyres if respecting the loading
by tyre.
The front steer non driven axle is equipped with 2 tyres having a size suitable for the axle
load. These 2 front tyres could be maintained along the test.
4.7.4. Load and Inflation Pressure
4.7.4.1. The static load on each rear driven test tyres must be between 20% and 55% of the tested
tyre load capacity written on the sidewall.
The vehicle front steer total static axle load should be between 60% and 160% of the driven
rear total axle load.
The static tyre load on the same driven axle should not differ by more than 10%.
4.7.4.2. The driven tyres inflation pressure shall be 70% of the one written on the sidewall.
The steer tyres are inflated at nominal sidewall pressure
If the pressure is not marked on the sidewall, refer to the specified pressure in applicable tyre
standards manuals corresponding to maximum load capacity.
4.7.5. Testing Runs
4.7.5.1. Mount first the set of reference tyres on the vehicle and when on the testing area.
Drive the vehicle at an initial constant speed between 4km/h and 11km/h and the gear ratio
capable of covering the speed range of at least 19km/h for the complete test programme
(e.g.R-T1-T2-T3-R).
The Recommended Gear ratio selected is 3rd or 4 and shall give a minimum 10% average
slip ratio in the measured range of speed.

For the reference tyre:
If the coefficient of variation of the average Acceleration "AA" for each group of min 6 runs of
the reference tyre is higher than 6%, discard all data and repeat the test for all tyres (the
candidate tyres and the reference tyre).
In addition and in order to take in account possible test evolution, the coefficient of validation
is calculated on the basis of the average values of any two consecutive groups of min 6 runs
of the reference tyre. If the coefficient of validation is greater than 6%, discard the data for all
the candidate tyres and repeat the test.
4.8.3. Calculation of the "Average AA"
coefficien t of variation =
Average2 − Average1
× 100
Average1
If R1 is the average of the "AA" values in the first test of the reference tyre, R2 is the average
of the "AA" values in the second test of the reference tyre, the following operations are
performed, according to Table 1:
Table 1
If the number of sets of
candidate tyres between two
successive runs of the
reference tyre is:
and the set of candidate tyres
to be qualified is:
then "Ra" is calculated by
applying the following:
1 R - T1 – R T1 Ra = ½ (R1 + R2)
2 R - T1 –T2 - R T1
T2
3 R - T1 – T2 – T3 - R T1
T2
T3
Ra = ⅔ R1 + ⅓ R2
Ra = ⅓ R1 + ⅔ R2
Ra = ¾ R1 + ¼ R2
Ra = ½ (R1 + R2)
Ra = ¼ R1 + ¾ R2
"Ta" (a = 1, 2, …) is the average of the AA values for a test of a candidate tyre.

4.9.2. Principle of the Approach
The principle lies upon the use of a control tyre and 2 different vehicles for the assessment of
a candidate tyre in comparison with a reference tyre.
One vehicle can fit the reference tyre and the control tyre, the other the control tyre and the
candidate tyre. All conditions are in conformity with Paragraph 4.7. above.
The first assessment is a comparison between the control tyre and the reference tyre. The
result (Snow Grip Index 1) is the relative efficiency of the control tyre compared to the
reference tyre.
The second assessment is a comparison between the candidate tyre and the control tyre. The
result (Snow grip index 2) is the relative efficiency of the candidate tyre compared to the
control tyre.
The second assessment is done on the same track as the first one. The air temperature must
be in the range of +/- 5°C of the temperature of the first assessment. The control tyre set is
the same set as the set used for the first assessment.
The Snow Grip performance Index of the candidate tyre compared to the reference tyre is
deduced by multiplying the relative efficiencies calculated above:
Snow Grip Index = SG1×SG2

APPENDIX 1
PICTOGRAM DEFINITION OF "ALPINE SYMBOL"
Minimum 15mm base and 15mm height.
Above drawing not to scale.

3.
Test vehicle (make, model and type, year): ......................................................................................
4.
Test tyre details ................................................................................................................................
4.1.
Tyre size designation and service description: .................................................................................
4.2.
Tyre brand and trade description: .....................................................................................................
4.3.
Test tyre data: ...................................................................................................................................
SRTT
Candidate
Candidate
SRTT
Tyre dimensions
Test rim width code
Tyre loads F/R (kg)
Load index F/R (%)
Tyre pressure F/R (kPa)
5. Test results: mean fully developed decelerations (m/s²) / traction coefficient .
Run number Specification SRTT Candidate Candidate SRTT
1
2
3
4
5
6
Mean
Std-deviation
CV (%) <6%
Validation SRTT (SRTT) <5%
SRTT average
Snow index 100

Part 2 – Test data
1.
Date of test: ....................................................................................................................................
2.
Location of test track: .....................................................................................................................
2.1.
Test track characteristics:
At start of tests
At end of tests
specification
Weather
Ambient temperature
-2°C to -15°C
Snow temperature
-4°C to -15°C
CTI index
80 to 90
Other
3.
Test vehicle (make, model and type, year): ...................................................................................
4.
Test tyre details ..............................................................................................................................
4.1.
Tyre size designation and service description: ..............................................................................
4.2.
Tyre brand and trade description: ..................................................................................................
4.3.
Test tyre data: ................................................................................................................................
SRTT (1st test) Candidate 1
Candidate 2 Candidate 3 SRTT (2nd test)
Tyre dimensions
Test rim width code
Tyre loads F/R (kg)
Load index F/R (%)
Tyre pressure F/R (kPa)

Tyres with Regard to Rolling Sound Emissions.