Regulation No. 117-01

Name:Regulation No. 117-01
Description:Rolling Tyre Noise and Adhesion on Wet Surfaces.
Official Title:Uniform Provisions Concerning the Approval of: Tyres with Regard to Rolling Sound Emissions and to Adhesion on Wet Surfaces.
Country:ECE - United Nations
Date of Issue:2005-04-06
Amendment Level:01 Series, Corrigendum 3
Number of Pages:46
Vehicle Types:Car, Component, Light Truck, Trailer
Subject Categories:Prior Versions
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Keywords:

tyre, test, approval, regulation, tyres, sound, vehicle, surface, type, paragraph, track, rolling, srtt, wet, class, temperature, testing, series, number, annex, level, measured, case, requirements, performance, candidate, speed, amendments, load, reference, adhesion, standard, accordance, means, approved, granted, surfaces, size, category, measurements, force, measurement, procedure, order, fitted, conditions, area, coefficient, date, index

Text Extract:

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E/ECE/324 )
E/ECE/TRANS/505 ) Rev.2/Add.116/Rev.1/Corr.3
June 18, 2009
STATUS OF UNITED NATIONS REGULATION
ECE 117-01
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF:
TYRES WITH REGARD TO ROLLING SOUND EMISSIONS
AND TO ADHESION ON WET SURFACES
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 of 30.04.09 to the 01 series of amendments
Date of Entry into Force: 10.03.09

REGULATION NO. 117
UNIFORM PROVISIONS CONCERNING THE APPROVAL OF TYRES WITH REGARD TO ROLLING
SOUND EMISSIONS AND TO ADHESION ON WET SURFACES
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 definitely discontinued
11.
Names and addresses of Technical Services responsible for conducting approval tests, and of
administrative departments
12.
Introductory provisions
ANNEXES
Annex 1
Annex 2
Annex 3
Annex 4
Annex 5
− Communication concerning the approval or extension or refusal or withdrawal of
approval or production definitely discontinued of a type of tyre with regard to "rolling
sound emission level" and "adhesion performance on wet surfaces" pursuant to
Regulation No. 117
− Arrangement of approval marks
Annex 2 − Appendix 1 Approval according to Regulation No. 117 coincident with
approval to Regulations Nos. 30 or 54
Annex 2 − Appendix 2 Extensions to combine approvals issued in accordance with
Regulations Nos. 117, 30 or 54
− Coast-by test method for measuring tyre-rolling sound emission
Annex 3 − Appendix Test report
− Specifications for the test site
− Test procedure for measuring wet grip
Annex 5 − Appendix Test report

(e)
For Class C1 tyres:
(i)
(ii)
In case of tyres submitted for approval of rolling sound emission levels,
whether normal or reinforced (or Extra Load);
In case of tyres submitted for approval of performance adhesion on wet
surfaces, whether normal or snow tyres with a speed category of Q or below
(160 km/h) or speed category R and above including H (≥ 170 km/h);
(f) The tread pattern (see Paragraph 3.2.1.).
2.2. "Brand name" or "Trade description" means the identification of the tyre as given by the
tyre manufacturer. The Brand name may be the same as that of the manufacturer and the
Trade description may coincide with the trade mark.
2.3. "Rolling sound emission" means the sound emitted from the contact between the tyres in
motion and the road surface.
2.4. "Tyre Class" means one of the following groupings:
2.4.1. Class C1 tyres: Tyres conforming to ECE Regulation No. 30;
2.4.2. Class C2 tyres: Tyres conforming to ECE Regulation No. 54 and identified by a load
capacity index in single formation lower or equal to 121 and a speed Category symbol
higher or equal to "N";
2.4.3. Class C3 tyres: Tyres conforming to ECE Regulation No. 54 and identified by:
(a)
(b)
A load capacity index in single formation higher or equal to 122; or
A load capacity index in single formation lower or equal to 121 and a speed Category
symbol lower or equal to "M".
2.5. "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, and Annex 5 for adhesion
on wet surfaces, to assess the conformity for the type approval of the type of tyre.
2.6. "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.
2.7. "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.
2.8. "Normal tyre" means a tyre intended for normal, everyday, on-road use.
2.9. "Special use tyre" means a tyre intended for mixed use both on- and off-road or for other
special duty.
2.10. "Snow tyre" means a tyre whose tread pattern, tread compound or structure are 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.

3.1.7. Tyre structure;
3.1.8. For Class C1 tyres, state whether;
(a)
(b)
Reinforced (or extra load) in case of approval with regard to rolling sound emission
level;
Speed Category Symbol "Q" or below (not including "H") or "R" and above
(including "H") in case of "snow" tyres for approval with regard to adhesion on wet
surfaces;
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 tyre performance (i.e. rolling
sound emission level or adhesion on wet surfaces, respectively) of the tread pattern(s) to be
used on the designated range of tyre sizes. This may be by drawing, photograph or
description, but 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
performance 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 3.1.4. above and the approval marking referred to in Paragraph 5, shall be
submitted once the production has been established, but no later than one year after the
date of granting of type approval.
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.
3.5. The laboratories and test facilities of a tyre manufacturer may be designated as an
approved laboratory and the type-approval authority shall have the option of being
represented during any tests.
4. MARKINGS
4.1. All tyres constituting the type of tyre must be marked as prescribed by either
ECE Regulation No. 30 or No. 54, as applicable.
4.2. In particular tyres must bear:
4.2.1. The manufacturer's name or trade mark;
4.2.2. The trade description (see Paragraph 2.2). However, the trade description is not required
when it coincides with the trade mark;
4.2.3. The tyre size designation;

5.3.2. The following suffixes have been already reserved to identify specific regulations on tyre
performance parameters:
S
W
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.
Other suffixes will be defined on need.
5.4. In the space referred to in Paragraph 4.3. and in accordance with the requirements of
Paragraph 4.4. 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, followed by suffix(es) "S" or "SW", placed to the right (or below) the
circle prescribed in Paragraph 5.4.1., if part of the original approval. If the approval is
extended subsequent to the original approval the addition sign "+" shall be placed in front of
the "S" or "SW" to denote an extension to the approval.
5.4.3. The suffix(es), and the identification to any relevant series of amendments, if any, as
specified in the communication form.
5.4.4. The marking on the tyre sidewalls of suffix(es) to the approval number removes the
requirement for any additional marking on the tyre of the specific type approval number for
conformity to the regulation(s) to which the suffix refers as per Paragraph 5.3.2. above.
5.5. If the tyre conforms to type approvals under one or more other Regulations annexed to the
Agreement in the country which has granted approval under this Regulation, the symbol
prescribed in Paragraph 5.4.1. need not be repeated. In such a case the additional
numbers and symbols of all the Regulations under which approval has been granted in the
country which has granted approval under this Regulation shall be placed adjacent to the
symbol prescribed in Paragraph 5.4.1. above.
5.6. Annex 2 to this Regulation gives examples of arrangements of approval marks.

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).
6.2.1. For Class C1 tyres, tested in accordance with either procedure given in Annex 5 to this
Regulation, the tyre shall meet the following requirements:
Category of use
snow tyre with a speed symbol ("Q" or below minus "H") indicating
a maximum permissible speed not greater than 160 km/h
snow tyre with a speed symbol ("R" and above, plus "H")
indicating a maximum permissible speed greater than 160 km/h
Wet grip index (G)
≥ 0.9
≥ 1.0
normal (road type) tyre ≥ 1.1
7. MODIFICATIONS OF THE TYPE OF PNEUMATIC 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.
8. CONFORMITY OF PRODUCTION
The conformity of production procedures shall comply with those set out in the Agreement,
Appendix 2 (E/ECE/324-E/ECE/TRANS/505/Rev.2) with the following requirements:
8.1. Any tyre approved under this Regulation shall be so manufactured as to conform to the
performance characteristics of the type of tyre approved and satisfy the requirements of
Paragraph 6 above;

12. INTRODUCTORY PROVISIONS
12.1. As from the date of entry into force of this Regulation, Contracting Parties applying this
Regulation shall not:
(a)
(b)
Refuse to grant ECE approval for a type of tyre under this Regulation; or
Prohibit the sale or entry into service of a tyre
if the tyre falls within the scope of this Regulation and complies with the requirements of this
Regulation.
12.2. As from August 4, 2003, a Contracting Party applying this Regulation shall refuse to grant
national approval of a type of tyre if the tyre falls within the scope of this Regulation and
does not comply with the rolling sound emissions requirements of this Regulation.
12.3. As from 24 months after the date of entry into force of the 01 series of amendments,
Contracting Parties applying this Regulation with respect to the adhesion level of tyres in
rolling conditions on wet surfaces shall grant approvals only if the tyre type to be approved
meets the requirements of this Regulation as amended by the 01 series of amendments.
12.4. As from the dates given below, a Contracting Party applying this Regulation shall refuse to
allow the sale or entry into service of a tyre which falls within the scope of this Regulation
and which does not meet the rolling sound emission requirements of this Regulation.
For Class C1 tyres up to 185 section width October 1, 2009
For Class C1 tyres over 185 up to 215 section width October 1, 2010
For Class C1 tyres over 215 section width October 1, 2011
For Class C2 and Class C3 tyres October 1, 2009
Prior to the above dates, Contracting Parties applying this Regulation shall not require for
the sale or entry into service of a replacement tyre which falls within the scope of this
Regulation, for it to comply with the rolling sound emission level requirements of this
Regulation.

10. Reason(s) of extension (if applicable): ................................................................................................
11. Any remarks: .......................................................................................................................................
12. Place: ...................................................................................................................................................
13. Date: ....................................................................................................................................................
14. Signature: ............................................................................................................................................
15. Annexed to this communication are: ...................................................................................................
15.1. A list of documents in the approval file deposited at the Administration services having delivered
the approval and which can be obtained upon request.
15.2. A list of tread-pattern designations: Specify for each trademark or brand name and trade
description the list of tyre size designations adding, in the case of Class C1 tyres, the mark
"reinforced" (or "extra load"), or the speed symbol of snow tyres, if so required by Paragraph 3.1.
of this Regulation.

APPENDIX 1
APPROVAL ACCORDING TO REGULATION No. 117 COINCIDENT WITH APPROVAL TO
REGULATIONS Nos. 30 OR 54
Example 1
a ≥ 12 mm
The above approval mark shows that the tyre concerned has been approved in the Netherlands (E4)
pursuant to Regulation No. 117 (marked by S (rolling sound)), under approval number 011234 and
Regulation No. 30, under approval number 023637. The first two digits of the approval number (01)
indicate that the approval was granted according to the 01 series of amendments, but Regulation No. 30
included the 02 series of amendments.
Example 2
a ≥ 12 mm
The above approval mark shows that the tyre concerned has been approved in the Netherlands (E4)
pursuant to Regulation No. 117 (marked by S (rolling sound) or SW (rolling sound and wet adhesion)),
under approval number 011234 and Regulation No. 30 under approval number 023637. The first two
digits of the approval number (01) indicate that the approval was granted according to the 01 series of
amendments, but Regulation No. 30 included the 02 series of amendments.

APPENDIX 2
EXTENSIONS TO COMBINE APPROVALS ISSUED IN ACCORDANCE WITH
REGULATIONS Nos. 117, 30 OR 54
Example 1
a ≥ 12 mm
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 023637. It
is also marked by + S (rolling sound) which indicates that its approval is extended under
Regulation No. 117. The first two digits of the approval number (02) indicate that the approval was
granted according to Regulation No. 30 which included the 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).
Example 2
a ≥ 12 mm
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 023637.
This indicates that the approval is for S (rolling sound) or S (rolling sound) and W (wet adhesion). The
S or SW followed by (01) indicates that it has had its approval extended under Regulation No. 117 which
included the 01 series of amendments. The first two digits of the approval number (02) indicate that the
approval was granted according to Regulation No. 30 which included the 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).

1.2. Speed Measurements
The vehicle speed shall be measured with instruments with accuracy of ± 1 km/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 ± 0.1 m 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 ≥ 0.1 m is covered.
1.4. Wind Measurement
The device must be capable of measuring the wind speed with a tolerance of ± 1 m/s. The
wind shall be measured at microphone height. The wind direction with reference to the
driving direction shall be recorded.
2. CONDITIONS OF MEASUREMENT
2.1. Test Site
The test site must consist of a central section surrounded by a substantially flat test
area. The measuring section must be level; the test surface must be dry and clean for all
measurements. The test surface shall not be artificially cooled during or prior the testing.
The test track must be such that the conditions of a free sound field between the sound
source and the microphone are attained to within 1 dB(A). These conditions shall be
deemed to be met if there are no large sound reflecting objects such as fences, rocks,
bridges or building within 50 m of the centre of the measuring section. The surface of the
test track and the dimensions of the test site shall be in accordance with Annex 4 to this
Regulation.

(c)
(d)
(e)
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.
2.5. Tyres
2.5.1. General
2.5.2. Tyre Loads
Four identical tyres shall be fitted on the test vehicle. In the case of tyres with a load
capacity index in excess of 121 and without any dual fitting indication, two of these tyres of
the same type and range must be fitted to the rear axle of the test vehicle; the front axle
must be fitted with tyres of size suitable for the axle load and planed down to the minimum
depth in order to minimize the influence of tyre/road contact noise while maintaining a
sufficient level of safety. Winter tyres that in certain Contracting Parties may be equipped
with studs intended to enhance friction shall be tested without this equipment. Tyres with
special fitting requirements shall be tested in accordance with these requirements
(e.g. rotation direction). The tyres must have full tread depth before being run-in.
Tyres are to be tested on rims permitted by the tyre manufacturer.
The test load Q for each tyre on the test vehicle shall be 50 to 90% of the reference load Q ,
but the average test load Q of all tyres shall be 75 ± 5% of the reference load Q .
For all tyres the reference load Q corresponds to the maximum mass associated with the
load capacity index of the tyre. In the case where the load capacity index is constituted by
two numbers divided by slash (/), reference shall be made to the first number.

3.3. Test Speed Range
The test vehicle speeds shall be within the range:
(a)
(b)
From 70 to 90 km/h for Class C1 and Class C2 tyres;
From 60 to 80 km/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)
80 km/h for Class C1 and Class C2 tyres,
70 km/h for Class C3 tyres.
4.2. Regression Analysis of Rolling Sound Measurements
The tyre-road rolling sound level L in dB(A) is determined by a regression analysis
according to:
where:
L = L − a × v
L
is the mean value of the rolling sound levels L , measured in db(A):
L =
1
n

L
n is the measurement number (n ≥ 16),
v is the mean value of logarithms of speeds V :
1
v = v with v = lg
n ∑
( V / V )
a
is the slope of the regression line in dB(A):
a =
∑ ( v − v) ( L − L)
∑ ( v − v)

Figure 1
Microphone Positions for the Measurement

4. Tyre test details:
4.1. Tyre size designation: ....................................................................................................................
4.2. Tyre service description: ................................................................................................................
4.3. Reference inflation pressure: ...................................................................................................kPa
4.4. Test data
Test mass (kg)
Tyre load index (%)
Inflation pressure
(cold) (kPa)
Front left Front right Rear left Rear right
4.5. Test rim width code: .......................................................................................................................
4.6. Temperature measurement sensor type: .......................................................................................
5. Valid Test results:
Run
No.
Test
Speed
km/h
Direction
of run
Sound level
left
measured
dB(A)
Sound level
right
measured
dB(A)
Air
temp.
°C
Track
temp.
°C
Sound level Sound level
left
temp. right
temp.
corrected
dB(A)
corrected
dB(A)
Comments
1
2
3
4
5
6
7
8
5.1. Regression line slope: ....................................................................................................................
5.2. Sound level after temperature correction according to Paragraph 4.3. of Annex 3: ............ dB(A)

2.5. Period of Testing
In order to check whether the surface continues to conform to the texture and voids content
or sound absorption requirements stipulated in this Standard, periodic testing of the surface
shall be done at the following intervals:
(a)
For residual voids content (VC) or sound absorption (α):
When the surface is new;
If the surface meets the requirements when new, no further periodical testing is
required. If it does not meet the requirement when it is new, it may do later because
surfaces tend to become clogged and compacted with time;
(b)
For texture depth (TD):
When the surface is new;
When the noise testing starts (NB: not before four weeks after laying);
Then every twelve months.
3. TEST SURFACE DESIGN
3.1. Area
When designing the test track layout it is important to ensure that, as a minimum
requirement, the area traversed by the vehicles running through the test strip is covered with
the specified test material with suitable margins for safe and practical driving. This will
require that the width of the track is at least 3 m and the length of the track extends beyond
Lines AA and BB by at least 10 m at either end. Figure 1 shows a plan of a suitable test site
and indicates the minimum area which shall be machine laid and machine compacted with
the specified test surface material. According to Annex 3, Paragraph 3.2., measurements
have to be made on each side of the vehicle. This can be made either by measuring with
two microphone locations (one on each side of the track) and driving in one direction, or
measuring with a microphone only on one side of the track but driving the vehicle in two
directions. If the latter method is used, then there are no surface requirements on that side
of the track where there is no microphone.

3.2.2. Design Guidelines
As a guide to the surface constructor, an aggregate grading curve which will give desired
characteristics is shown in Figure 2. In addition, Table 1 gives some guidelines in order to
obtain the desired texture and durability. The grading curve fits the following formula:
where:
P (% passing) = 100 × (d/d ) 1/2
d = square mesh sieve size, in mm
d = 8 mm for the mean curve
= 10 mm for the lower tolerance curve
= 6.3 mm for the upper tolerance curve
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)
The sand fraction (0.063 mm < square mesh sieve size < 2 mm) 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 residual voids content has to be determined for each core, then the average value from
all cores shall be calculated and compared with the requirement of Paragraph 2.1. In
addition, no single core shall have a voids value, which is higher than 10%.
The test surface constructor is reminded of the problem, which may arise when the test area
is heated by pipes or electrical wires and cores must be taken from this area. Such
installations must be carefully planned with respect to future core drilling locations. It is
recommended to leave a few locations of size approximately 200 mm × 300 mm where
there are no wires/pipes or where the latter are located deep enough in order not to be
damaged by cores taken from the surface layer.
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.). The sound absorption shall be measured in the
range between 400 Hz and 800 Hz and in the range between 800 Hz and 1,600 Hz (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 Macrotexture 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.
5.2. Maintenance of the Surface
Loose debris or dust, which could significantly reduce the effective texture depth must 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.

ANNEX 5
TEST PROCEDURE FOR MEASURING WET GRIP
1. GENERAL TEST CONDITIONS
1.1. Track Characteristics
The track shall have a dense asphalt surface with a gradient in any direction not
exceeding 2%. It shall be of uniform age, composition, and wear and shall be free of loose
material or foreign deposits. The maximum chipping size shall be 10 mm (tolerances
permitted from 8 mm to 13 mm) and the sand depth measured as specified in
ASTM E-965 shall be 0.7 ± 0.3 mm.
The surface friction value for the wetted track shall be established by one or other of the
following methods:
1.1.1. Standard Reference Test Tyre (SRTT) Method
When tested using the SRTT and the method given in Paragraph 2.1. the average peak
brake force coefficient (pbfc) shall be between 0.6 and 0.8. The measured values shall be
corrected for the effects of temperature as follows:
pbfc = pbfc (measured) + 0.003 × 5(t − 20)
where "t" is the wetted track surface temperature in degrees Celsius.
The test shall be conducted using the lanes and length of the track to be used for the wet
grip test;
1.1.2. British Pendulum Number (BPN) Method
The averaged British pendulum number (BPN) of the wetted track, measured in
accordance with the procedure given in the American Society for Testing and Materials
(ASTM) Standard 303-93 (re-approved 1998) and using the pad as specified in
ASTM Standard E 501-94, shall be between 40 and 60 after temperature correction.
Unless temperature correction recommendations are indicated by the pendulum
manufacturer, the following formula can be used:
BPN = BPN (measured value) + 0.34 × t − 0.0018 × t² − 6.1
where "t" is the wetted track surface temperature in degrees Celsius.
In the lanes of the track to be used during the wet grip tests, the BPN shall be measured at
intervals of 10 m 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 by 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.

2.1.1.5. In the case of vehicles that incorporate a track wetting system, the water delivery nozzle(s)
shall be such that the resulting water film is of uniform section extending at least 25 mm
beyond the width of the tyre contact patch. The nozzle(s) shall be directed downwards at
an angle of 20° to 30° and shall contact the track surface between 250 mm and 450 mm in
front of the centre of the tyre contact patch. The height of the nozzle(s) shall be 25 mm or
the minimum to avoid any obstacles on the track surface without exceeding a maximum of
100 mm. Water delivery rate shall ensure a water depth of 0.5 mm to 1.5 mm and shall be
consistent throughout the test to within ± 10%. Note that a typical rate for testing at
65 km/h will be 18 ls per metre of wetted track surface width.
The system shall be able to deliver the water such that the tyre, and track surface in front
of the tyre, is wetted before the start of braking and throughout the duration of the test.
2.1.2. Test Procedure
2.1.2.1. The test tyre shall be trimmed to remove any moulding protrusions that are likely to affect
the test.
2.1.2.2. The test tyre shall be mounted on the test rim declared by the tyre manufacturer in the
approval application and shall be inflated to 180 kPa in the case of the SRTT and standard
load tyre or 220 kPa in the case of a reinforced or extra load tyre.
2.1.2.3. 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.
2.1.2.4. The tyre shall be loaded to:
(a)
(b)
Between 445 kg and 508 kg in the case of the SRTT; and
Between 70% and 80% of the load value corresponding to the load index of the tyre
in any other case.
2.1.2.5. Shortly before testing, the track shall be conditioned by carrying out at least ten braking
tests on the part of the track to be used for the performance test programme but using a
tyre not involved in that programme.
2.1.2.6. Immediately prior to testing, the tyre inflation pressure shall be checked and reset, if
necessary, to the values given in Paragraph 2.1.2.2.
2.1.2.7. The test speed shall be between 63 km/h and 67 km/h and shall be maintained between
these limits throughout the test run.
2.1.2.8. The direction of the test shall be the same for each set of tests and shall be the same for
the test tyre as that used for the SRTT with which its performance is to be compared.
2.1.2.9. The brakes of the test wheel assembly shall be applied such that peak braking force is
achieved within 0.2 s and 0.5 s of brake application.
2.1.2.10. In the case of a new tyre, two test runs shall be carried out to condition the tyre. These
tests may be used to check the operation of the recording equipment but the results shall
not be taken into account in the performance assessment.

2.1.2.15. The wet grip index (G) shall be calculated as:
2.2. Standard Vehicle Procedure
pbfc of candidate tyre
G =
pbfc of SRTT
2.2.1. The vehicle shall be a standard M Category vehicle, capable of a minimum speed of
90 km/h and equipped with an anti-lock braking system (ABS).
2.2.1.1. The vehicle shall not be modified except:
(a)
(b)
To allow the fitting of an increased range of wheel and tyre sizes;
To allow mechanical (including hydraulic, electrical or pneumatic) operation of the
service brake control. The system may be operated automatically by signals from
devices incorporated in, or adjacent to, the track.
2.2.2. Test Procedure
2.2.2.1. The test tyres shall be trimmed to remove any moulding protrusions that are likely to affect
the test.
2.2.2.2. The test tyre shall be mounted on the test rim declared by the tyre manufacturer in the
approval application and shall be inflated to 220 kPa in all cases.
2.2.2.3. 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.
2.2.2.4. The static load on the tyre shall be:
(a)
(b)
Between 381 kg and 572 kg in the case of the SRTT; and
Between 60% and 90% of the load value corresponding to the load index of the tyre
in any other case.
The variation in load on tyres on the same axle shall be such that the load borne by the
more lightly loaded tyre shall not be less than 90% of that of the tyre bearing the greater
load.
2.2.2.5. Shortly before testing, the track shall be conditioned by carrying out at least ten braking
tests from 90 km/h to 20 km/h on the part of the track to be used for the performance test
programme but using tyres not involved in that programme.
2.2.2.6. Immediately prior to testing, the tyre inflation pressure shall be checked and reset, if
necessary, to the values given in Paragraph 2.2.2.2.

2.2.2.13. Using the value of the average mfdd for each series of test runs:
In the case of the order of testing R1 − T − R2, the mfdd of the SRTT to be used in the
comparison of the performance of the candidate tyre shall be taken to be:
where:
(R1 + R2)/2
R1 is the average mfdd for the first series of test runs of the SRTT and R2 is the average
mfdd for the second series of test runs of the SRTT
In the case of the order of testing R1 − T1 − T2 − R2, the mfdd of the SRTT shall be taken
to be:
2/3 R1 + 1/3 R2 for comparison with the candidate Tyre T1 and
1/3 R1 + 2/3 R2 for comparison with the candidate Tyre T2
In the case of the order of testing R1 − T1 − T2 − T3 − R2, the mfdd of the SRTT shall be
taken to be:
3/4 R1 + 1/4 R2 for comparison with the candidate Tyre T1
(R1 + R2)/2 for comparison with the candidate Tyre T2 and
1/4 R1 + 3/4 R2 for comparison with the candidate Tyre T3
2.2.2.14. The wet grip index (G) shall be calculated as:
averaged mfdd of candidate tyre
G =
mfdd of SRTT
2.2.2.15. 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.
2.2.2.15.1. The wet grip index of the control tyre relative to the SRTT (G1) and of the candidate tyre
relative to the control tyre (G2) shall be established using the procedure in
Paragraphs 2.2.2.1 to 2.2.2.15.
The wet grip index of the candidate tyre relative to the SRTT shall be the product of the
two resulting wet grip indices, that is G1 × G2.
2.2.2.15.2. The track, and the portion of the track, shall be the same for all of the tests and the
ambient conditions shall be comparable, for example, the surface temperature of the
wetted track shall be within ± 5° C. All tests shall be completed within the same day.
2.2.2.15.3. 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.

APPENDIX
TEST REPORT (Adhesion on Wet Surface)
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. Adhesion coefficient on wet surfaces relative to SRTT according to Paragraphs 2.1.2.15. or
2.2.2.15.: ........................................................................................................................................
8. Comments (if any): .........................................................................................................................
9. Date: ...............................................................................................................................................
10. Signature: .......................................................................................................................................
Part 2 − Test data
1. Date of test: ....................................................................................................................................
2. Test vehicle (make, model, year, modifications, etc. or trailer identification): ...............................
........................................................................................................................................................
3. Location of test track: .....................................................................................................................
3.1. Test track characteristics: ..............................................................................................................
3.2. Issued by: .......................................................................................................................................
3.3. Method of certification: ...................................................................................................................
4. Test tyre details: .............................................................................................................................
4.1. Tyre size designation and service description: ..............................................................................
4.2. Tyre brand and trade description: ..................................................................................................
4.3. Reference inflation pressure: kPa ..................................................................................................

Rolling Tyre Noise and Adhesion on Wet Surfaces.