Thông tư 57/2011/TT-BGTVT

CIRCULAR

ON PROMULGATION OF THREE NATIONAL TECHNICAL REGULATIONS ON AUTOMOTIVE PARTS

Pursuant to the Law on Technical Standards and Regulations dated June 29, 2006;

Pursuant to the Government's Decree No. 127/2007/ND-CP dated August 01, 2007 on the implementation of certain articles of the Law on Technical Standards and Regulations;

Pursuant to the Government’s Decree No. 51/2008/ND-CP dated April 22, 2008 on the functions, missions, authority and organizational structure of the Ministry of Transport;

At the request of the Head of the Department of Science and Technology and the Head of the Vietnam Register;

Minister of Transport promulgates:

Article 1. The enclosure of three following national technical regulations on automotive parts to this Circular:

1. National technical regulation on safety glazing equipped on vehicle;

No. QCVN 32:2011/BGTVT.

2. National technical regulation on rear view mirrors for automobiles;

No. QCVN 33:2011/BGTVT.

3. National technical regulation on pneumatic tyres for automobiles;

No. QCVN 34:2011/BGTVT.

Article 2. This Circular comes into force 6 months after the date that it is signed.

Article 3. Chief of Office of the Ministry, Chief of Inspectorate of the Ministry, Heads of Departments, Head of Vietnam Register, Heads of concerned authorities and organizations, relevant individuals are responsible for implementing this Circular./.

QCVN 34:2011/BGTVT

NATIONAL TECHNICAL REGULATION ON PNEUMATIC TYRES FOR AUTOMOBILES

Preamble

QCVN 34:2011/BGTVT is compiled by Vietnam Register, is presented by Department of Science and Technology for approval, and is issued by Ministry of Transport under the Circular No. 57/2011/TT-BGTVT dated November 17, 2011.

This technical regulation is compiled on the basis of TCVN 7226:2002 and TCVN 7227:2002.

NATIONAL TECHNICAL REGULATION ON PNEUMATIC TYRES FOR AUTOMOBILES

1. GENERAL

1.1. Scope

This document regulates technical requirements for new pneumatic tyres (referred to as tyres) equipped in automobiles, trailers and semi-trailers, except:

- Tyres for speeds lower than 60 km/h and in excess of 300 km/h.

- Tyres for racing and sports.

1.2. Regulated entities

This document applies to manufacturers, assemblers and importers of tyres, producers and organizations involved in testing, inspection and certification of technical quality and safety of tyres for automobiles.

1.3. Terminology

In this document, the following phrases are construed as follows:

1.3.1. Type of tyre: Tyres of the same type bear the identical brand name, derive from a single manufacturer and do not differ in one of the following primary technical respects:

1.3.1.1. Tyre-size designation.

1.3.1.2 Category of use (normal tyre intended for normal on-road use; special use tyre for both normal on-road use and for special use in, for example, off-road conditions; snow tyre or mud tyre).

1.3.1.3. Structure (diagonal or bias-ply, bias-belted, radial).

1.3.1.4. Speed category.

1.3.1.5. Load-capacity index.

1.3.1.6. Tyre cross-section;

1.3.2. Tyre structure: as specified below (Picture 1):

1.3.2.1. Diagonal or bias-ply: A tyre structure in which the ply cords extend to the beads and are laid at alternate angles substantially less than 90° to the centre line of the tread.

1.3.2.2. Bias-belted: A tyre structure of diagonal or bias-ply type in which the carcass is restricted by a belt comprising two or more layers of inextensible cord material laid at alternate angles close to those of the carcass.

1.3.2.3. Radial: A tyre structure in which the ply cords extend to the beads and are laid at 90° to the centre line of the tread, the carcass being stabilized primarily by an inextensible circumferential belt.

1.3.2.4. Reinforced: A tyre structure in which the carcass is more enduring than that of the corresponding standard tyre.

1.3.3. Bead: The part of a tyre which is of such shape and structure as to fit the rim and hold the tyre on it.

1.3.4. Cord: The strands forming the structure of the plies in the tyres.

1.3.5. Ply: A layer of rubber-coated parallel cords.

1.3.6. Carcass: The part of a tyre other than the tread and the rubber sidewalls which, when inflated, bears the load.

1.3.7. Tread: The part of a tyre which comes into contact with the ground, protects the carcass against mechanical damage and contributes to ground adhesion.

1.3.8. Sidewall: The part of a tyre between the tread and the area designed to be covered by the rim flange.

1.3.9. Tread groove: The space between two adjacent ribs or blocks in the tread pattern.

1.3.10. Principal grooves: The wide grooves positioned in the central zone of the tyre tread.

1.3.11. Section width S: The linear distance between the outsides of the sidewalls of an inflated tyre, excluding elevations due to labeling, decorative or protective bands or ribs.

1.3.12. Overall width: The linear distance between the outsides of the sidewalls of an inflated tyre, including decorative and protective bands or ribs, elevated label; however, the overall width shall be equal to the tread width if the latter is more widely spaced than the section width.

1.3.13. Section height H: A distance equal to half the difference between the outer diameter of the tyre and the nominal rim diameter.

1.3.14. Nominal aspect ratio Ra: One hundred times the number obtained by dividing the section height (H) by the nominal section width (S₁), both dimensions expressed in the same units.

1.3.15. Outer diameter D: The overall diameter of a new tyre inflated to the pressure specified by the manufacturer.

1.3.16. Tyre-size designation: consisting of:

1.3.16.1. Nominal section width (S₁) which is expressed in mm, except in the case of types of tyre for which the size designation is shown in the first column of the tables in Annex 5 to this Regulation.

1.3.16.2. Nominal aspect ratio (Ra), except in the case of certain types of tyre which are shown in the first column of the tables in Annex 5 to this Regulation.

1.3.16.3 Nominal rim diameter (d) which is expressed either by codes (numbers below 100) or in millimeters (numbers above 100).

The "d" symbol expressed in millimeters is shown by codes in Table 1.

Picture 1: Tyre cross-section

Table 1 - Code of "d" symbol

1.3.17. Nominal rim diameter (d): The diameter of the rim on which a tyre is designed to be mounted.

1.3.18. Rim: The support for a tyre-and-tube assembly, or for a tubeless tyre, on which the tyre beads are seated;

1.3.19. Theoretical rim: The notional rim whose width would be equal to X times the nominal section width of a tyre. The value of X shall be specified by the manufacturer of that tyre.

1.3.20. Measuring rim: The rim on which a tyre must be fitted for dimensional measurements.

1.3.21. Test rim: The rim on which a tyre must be fitted for testing.

1.3.22. Chunking: The breaking away of pieces of rubber from the tread;

1.3.23. Cord separation: The parting of the cords from their rubber coating.

1.3.24. Ply separation: The parting of adjacent plies.

1.3.25. Tread separation: The pulling away of the tread from the carcass.

1.3.26. Load-capacity index: A number associated to the highest load a tyre can carry at the speed corresponding to the associated speed category in conformity with the requirements governing utilization specified by the manufacturer. The list of these indices and their corresponding loads is given in Annex 1 to this Regulation.

1.3.27. Table of load-capacity variation with speed

The table, in Annex 4, showing the load variations which a tyre can withstand when used at speeds different from that conforming to its nominal-speed-category symbol, with reference to the load capacity of the tyre when used at the rate speed.

1.3.28. Speed category: The maximum speed which the tyre can sustain. Speed category is expressed by symbols in Table 2.

Table 2 - Symbol of speed categories

1.3.29. Snow tyre: A tyre whose tread pattern and structure are primarily designed to ensure in mud and fresh or melting snow a performance better than that of a normal tyre. The tread pattern of a snow tyre generally consists of groove (rib) and/or solid-block elements more widely spaced than on a normal tyre. The symbols of this type of tyre are commonly “M+S” or “M.S” or “M&S”.

1.3.30. Multi-service tyre "MST”: A tyre suitable for normal on-road use and for special off-road use.

1.3.31. Special use tyre: A tyre that is used in special off-road conditions. The symbols of this type of tyre are "ET” or “ML” or "MPT”.

1.3.32. Temporary-use spare tyre: A tyre that is different from a normal tyre fitted to a vehicle and is only for temporary use under special driving conditions.

1.3.3. T-type temporary-use spare tyre: A type of spare tyre for temporary use at inflation pressures higher than those established for standard and reinforced tyres.

1.3.34. Maximum load rating: The maximum mass the tyre can withstand:

1.3.34.1. For speeds not exceeding 210 km/h, the maximum load rating shall not exceed the value associated with the load capacity index of the tyre.

1.3.34.2. For speeds higher than 210 km/h but not exceeding 240 km/h (tyres classified with speed category symbol "V"), the maximum load rating shall not exceed the percentage of the value associated with the load capacity index of the tyre, indicated in the Table 3 below, with reference to the speed capability of the vehicle to which the tyre is fitted.

Table 3 - Load in proportion to the maximum load rating at speeds ranging from 215 km/h to 240 km/h

For intermediate maximum speeds, linear interpolations of the maximum load rating are allowed.

1.3.34.3. For speeds higher than 240 km/h but not exceeding 270 km/h (tyres classified with speed category symbol "W"), the maximum load rating shall not exceed the percentage of the value associated with the load capacity index of the tyre, indicated in Table 4 below, with reference to the speed capability of the vehicle to which the tyre is fitted.

Table 4 - Load in proportion to the maximum load rating at speeds ranging from 240 km/h to 270 km/h

For intermediate maximum speeds, linear interpolations of the maximum load rating are allowed.

1.3.34.3. For speeds higher than 270 km/h (tyres classified with speed-category symbol "Y"), the maximum load rating shall not exceed the percentage of the value associated with the load capacity index of the tyre, indicated in Table 5 below, with reference to the speed capability of the vehicle to which the tyre is fitted.

Table 5 - Load in proportion to the maximum load rating at speeds ranging from 270 km/h to 300 km/h

For intermediate maximum speeds, linear interpolations of the maximum load rating are allowed.

1.3.35. Bead separation: The pulling away of elements from the bead.

1.3.36. Belt separation: The pulling away of rubber between belt layers or between the belt and the cord layer.

1.3.37. Cracking: The cracking of rubber in the tread, the sidewalls or the inside of a tyre extending to the ply.

1.3.38. Internal rubber layer separation: The pulling away of the internal rubber layer from the ply.

1.3.39. Open splices: Open splices on the surface of a tyre, sidewalls and internal rubber layer extending to the ply.

1.3.40. Sidewall separation: The pulling away of rubber from the plies of the sidewalls.

1.3.41. Test drum speed: The speed at the outer face of a steel drum used for testing a tyre.

1.3.42. Tyre speed: The speed at the contact point of a tyre and a test drum.

1.3.43. Maximum speed: The speed corresponding to the speed symbol on a tyre or the maximum speed of a tyre specified by the manufacturer.

1.3.44. Test drum: A smooth drum made of steel, 1.70 m ± 1% or 2.0 m ± 1% in diameter, having an expanse wider than the overall width of the tested tyre. The test drum shall generate the testing speed required.

1.3.45. Tyre load generator:  A hydraulic system structured to generate static load or an equivalent system, with accuracy of ± 1.5 % of full scale and speed accuracy within ± 3% of full scale.

1.3.46. Tread-wear indicator: The projections within the tread grooves designed to give a visual indication of the degree of wear of the tread.

2. TECHNICAL PRESCRIPTIONS

A tyre shall be examined and tested as to satisfy the requirements in Paragraph 2.1, 2.2 and 2.3 below:

2.1. General technical prescriptions

2.1.1. Markings

Markings shall be displayed on both sidewalls in the case of symmetrical tyres and on the outer sidewall in the case of asymmetrical tyres. Contents to be marked:

2.1.1.1. The manufacturer’s name or trade mark.

2.1.1.2. The tyre-size designation as defined in Paragraph 1.3.16 of this Regulation.

2.1.1.3. An indication of the structure as follows:

- On diagonal (bias-ply) tyres, no marking or the letter "D" placed in front of the rim diameter marking.

- On bias-belted tyres, the letter "B" placed in front of the rim-diameter marking and, in addition, the word "BIAS-BELTED”.

- On radial-ply tyres, the letter "R" placed in front of the rim-diameter marking, and, optionally, the word "RADIAL". On these tyres designed for speeds in excess of 240 km/h, the letter "R" may be replaced with the inscription "ZR".

2.1.1.4. Speed-category symbol.

2.1.1.5. Load-capacity index.

2.1.1.6. The inscription “M+S” or “MS” or “M&S” on snow tyres.

2.1.1.7. The inscription “ET” or “ML” or “MPT” on special use tyres.

2.1.1.8. The word “TUBELESS” on tyres without an inner tube.

2.1.1.9. The word “REINFORCED” on reinforced tyres.

2.1.1.10. The date of manufacture in the form of a group of four digits in which the first two show the week (month) and the last two show the year of manufacture.

2.1.1.11. The pressure index "PSI" shown on a sidewall; see Annex 2 for the relation between the pressure index and the units of pressure.

2.1.2. Tread-wear indicator

A tyre shall include not less than six transverse rows of wear indicators, approximately equally spaced and situated in the principal grooves of the tread, along the circumference of the tyre. The tread-wear indicators shall be such that they cannot be confused with other elements on the surface of the tread.

However, in the case of tyres of a nominal diameter of 12 or less, four rows of tread-wear indicators shall be acceptable.

The tread-wear indicators must indicate the degree of wear, with a tolerance of +0.60/-0.00 mm, when the tread grooves are no longer more than 1.6 mm deep.

The height of tread-wear indicators is determined by measuring the difference between the depth, from the tread's surface to the top of the tread-wear indicator and to the bottom of the tread groove close to the slope at the base of the tread-wear indicator.

2.2 Dimensions of tyres

Dimensions of a tyre shall be included in its markings and accord with the standards specified by the manufacturer.

2.2.1. Section width of a tyre:

2.2.1.1. The section width shall be calculated by the following formula:

S = S₁ + K (A - A₁)

where:

- S: the section width expressed in millimeter and measured on the measuring rim;

- S₁: the nominal section width expressed in millimeter and shown on the sidewall of the tyre in the designation of the tyre as prescribed;

- A: the width (expressed in millimeter) of the measuring rim, as specified by the manufacturer;

- A₁: the width (expressed in millimeter) of the theoretical rim. A₁ shall equal S1 multiplied by the factor X, as specified by the manufacturer;

- K equals 0.4.

For the types of tyres for which the designation is prescribed in the first column of the tables in Annex 5 to this Regulation, the section width S shall be as given in these tables.

2.2.1.2. Specifications of tyre section width:

The overall width of a tyre may be less than the section width S determined pursuant to Paragraph 2.2.1.1.

The overall width of a tyre may exceed the section width S by the following percentages:

a) With regard to cars and trailers towed by a car:

- In diagonal tyres: 6%;

- In radial-ply tyres: 4%.

- In addition, if the tyre has special protective bands, the figure as increased by such tolerance may be exceeded by 8 (mm).

b) With regard to other automobiles, trailers and semi-trailers towed by such automobiles:

- In diagonal tyres: 8%;

- In radial-ply tyres: 4%.

- In addition, for tyres with section width exceeding 305 mm intended for dual mounting, the tolerance shall be:

+ In diagonal tyres: 4%;

+ In radial-ply tyres: 2%.

2.2.2. Outer diameter of a tyre:

2.2.2.1 The outer diameter of a tyre shall be calculated by the following formula:

D = d + 2H

where:

- D: the outer diameter expressed in millimeter;

- d: the nominal rim diameter expressed in millimeter;

- H: the nominal section height expressed in millimeter, equal to S x 0.01 R_a

where:

+ S₁: the nominal section width expressed in millimeter;

+ R_a:  the nominal aspect ratio.

For the types of tyres for which the designation is prescribed in the first column of the tables in Annex 5 to this Regulation, the outer diameter shall be as given in these tables.

2.2.2.2. Specifications of tyre outer diameter:

The outer diameter of a tyre must not be outside the values D_min and D_max obtained from the following formula:

D_min = d + (2H x a)

D_max = d + (2H x b)

where:

a) For sizes listed in Annex 5:

H = 0.5 (D-d);

b) For other sizes not listed in Annex 5:

“H” and “d” are as defined in Paragraph 2.2.2.1

c) Coefficients a and b are respectively:

- Coefficient a = 0.97

- Coefficient b, as defined in Table 6:

Table 6 - Coefficient b

d) For snow tyres, the outer diameter (D_max) may be exceeded by 1 percent when calculated as above.

2.2.3. Measuring of tyre size

2.2.3.1. Mount the tyre on the measuring rim specified by the manufacturer pursuant to Paragraph 3.2.1.12. of this Regulation and inflate it to the following pressure:

a) With regard to cars and trailers towed by a car:

- Inflate the tyre to a pressure of 300 to 350 kPa.

- Adjust the pressure as follows:

+ Standard bias-belted tyres: to 170 kPa.

+ Diagonal (bias-ply) tyres: as per Table 7,

Table 7 - Pressure adjustment

+ Standard radial tyres: to 180 kPa.

+ Reinforced tyres: to 230 kPa.

+ T-type temporary-use spare tyres: to 420 kPa.

b) With regard to other automobiles, trailers and semi-trailers towed by such automobiles:

- Inflate and adjust the tyre to the pressure specified by the manufacturer pursuant to Paragraph 3.2.1.13.

2.2.3.2. Condition the tyre mounted on its rim at the ambient room temperature for not less than 24 hours.

2.2.3.3. Measure the overall width by caliper at six equally-spaced points, taking the thickness of the protective ribs or bands into account. The highest measurement so obtained is taken as the overall width.

2.2.3.4. Determine the outer diameter by measuring the maximum circumference and dividing the figure so obtained by π (3.1416).

2.3. Testing of load/ speed and endurance

2.3.1. Tyres shall undergo the load/ speed performance and endurance test carried out by the procedure described in Annex 3 to this Regulation.

2.3.2. A tyre which, after undergoing the load/ speed performance and endurance test, does not exhibit any tread separation, ply separation, cord separation, chunking or broken cords shall be deemed to have passed the test.

2.3.3. The outer diameter of the tyre, measured six hours after the load/ speed performance and endurance test, must not differ by more than ± 3.5% from the outer diameter as measured before the test.

3. ADMINISTRATION

3.1. Testing methods

New tyres manufactured and imported must be tested pursuant to the Circular No. 30/2011/TT-BGTVT dated April 15, 2011 by the Minister of Transport on “Technical safety and quality test and environment protection with regard to the manufacture of motor vehicles.”

3.2. Technical documentation and sampling

Manufacturers and importers of tyres, when desiring to carry out a test, must provide the testing institutions with technical documents and samples specified in Paragraph 3.2.1 and 3.2.2.

3.2.1. Requirements for technical documentation

Technical documentation and drawings must indicate:

3.2.1.1. The trade name or mark;

3.2.1.2. The tyre-size designation as defined in Paragraph 1.3.16 of this Regulation.

3.2.1.3. Category of use (normal, special-use or snow tyre);

3.2.1.4. Structure: diagonal or bias-ply (ply-rating number), bias belted, radial;

3.2.1.5. Speed category;

3.2.1.6. Load-capacity index of the tyre;

3.2.1.7. Pressure index of the tyre;

3.2.1.8. Whether the tyre is to be use with or without an inner tube;

3.2.1.9. Whether the tyre is “standard” or “reinforced”.

3.2.1.10. Overall dimensions: Overall section width, overall outer diameter;

3.2.1.11. The rims on which the tyre is mounted;

3.2.1.12. Test rim;

3.2.1.13. Test pressure and measuring pressure;

3.2.1.14. The factor X referred to in Paragraph 1.3.19;

3.2.1.15. Drawing(s) or photo(s) of the sample tread: The drawing of the tyre mounted on the rim of equivalent size and inflated to the defined pressure.

3.2.2. Sampling

Three samples of each tyre of tyre (fully mounted on rims with, if applicable, the inner tube) shall be tested.

3.3. Test reporting

Testing institutions shall be responsible for testing each type of tyre and reporting the result of test(s) as per this Regulation.

3.4. Product types tested and qualified according to regulations and registered in writing as per this Regulation shall be certified in writing as described in Annex 6.

4. IMPLEMENTATION

4.1. Vietnam Register shall be responsible for implementing this Regulation and providing guidelines thereof with regard to the inspection of technical safety and quality of tyres manufactured and imported.

4.2. Duration: This Regulation shall apply to new and certified types of tyre 02 and 04 years, respectively, after the date that it takes effect.

ANNEX 1

LOAD-CAPACITY INDICES / CORRESPONDING MASS

Li - Load capacity index                                     kg - Corresponding mass (kg)

ANNEX 2

PRESSURE INDEX AND UNITS OF PRESSURE

ANNEX 3

PROCEDURE FOR LOAD/ SPEED PERFORMANCE TESTS

3.1. Preparing the tyre

3.1.1. Mount a new tyre on the test rim specified by the manufacturer pursuant to Paragraph 3.2.1.12 of this Regulation.

3.1.2. Inflate the tyre to the appropriate pressure as given below:

3.1.2.1. For cars and trailers towed by a car, the pressure is given in Table 1 of this Annex.

Table 1 - Inflation pressure test (kPa)

- T-type temporary-use spare tyres: to 420 kPa.

3.1.2.2. For other automobiles, trailers and semi-trailers towed by such automobiles:

- Inflate the tyre to the pressure specified by the manufacturer pursuant to Paragraph 3.2.1.13 of this Regulation.

3.1.3. Condition the tyre-and-wheel assembly at test room’s temperature for not less than 03 hours.

3.1.4. Readjust the tyre pressure to that specified in Paragraph 3.1.2.1 or 3.1.2.2 of this Annex.

3.1.5. The manufacturer may request the use of a test-inflation pressure differing from those given under Clause 3.1.2 of this Annex. In such a case, the tyre shall be inflated to the pressure requested by the manufacturer.

3.2. Carrying out the test

3.2.1. With regard to cars and trailers towed by a car:

3.2.1.1. Mount the tyre-and-wheel assembly on a test axle and press it against the outer face of a smooth test drum 1.70 m ± 1% or 2 m ± 1% in diameter.

3.2.1.2. Apply to the test axle a load equal to 80% of:

- The maximum load rating equated to the load capacity index for tyres with speed symbols L to H inclusive.

- The maximum load rating associated with a maximum speed of 240 km/h for tyres with speed symbol "V" (see Paragraph 1.3.34.2 of this Regulation).

- The maximum load rating associated with a maximum speed of 270 km/h for tyres with speed symbol "W" (see Paragraph 1.3.34.3 of this Regulation).

- The maximum load rating associated with a maximum speed of 300 km/h for tyres with speed symbol "Y" (see Paragraph 1.3.34.4 of this Regulation).

3.2.1.3. Throughout the test, the tyre pressure must not be adjusted and the test load must be kept constant.

3.2.1.4. During the test, the temperature in the test room must be maintained at between 20°C and 30°C or at a higher temperature if the manufacturer agrees.

3.2.1.5. Carry out the test continuously, without interruption, in conformity with the following steps:

- Pass from zero speed to initial test speed in 10 minutes.

- Initial test speed:

+ 30 km/h less than the maximum nominal speed of the tyre if the test drum is 2.0 m in diameter,

+ 40 km/h less than the initial speed if the test drum is 1.7 m in diameter.

- Speed increment: 10 km/h.

- Duration of test at each step: 10 minutes (except the last step).

- Duration of test at the last step: 20 minutes.

- Total test duration: 1 hour.

- Maximum test speed:

+ The maximum nominal speed of the tyre if the test drum is 2.0 m in diameter;

+ 10 km/h less than the maximum nominal speed of the tyre if the test drum is 1.7 m in diameter.

However, for tyres suitable for maximum speed of 300 km/h (symbol “Y”), the duration of the test is 20 minutes at the last speed step

3.2.2. For other automobiles, trailers and semi-trailers towed by such automobiles:

3.2.1.1. Mount the tyre-and-wheel assembly on a test axle and press it against the outer face of a test drum 1.70 m ± 1% or 2 m ± 1% in diameter.

3.2.2.2. Carry out the following procedure of test.  Where the tyre has load-capacity indices for both single and twinned utilization, the reference load for single utilization shall be taken as the basis for the test loads.

3.2.2.2.1. For tyres with speed category symbols “Q” and above, the test procedure is defined in Clause 3.3 of this Annex.

3.2.2.2.2. For other types of tyre, the endurance test procedure is specified in Clause 3.4 of this Annex.

3.2.2.3. Throughout the test, the tyre pressure must not be adjusted and the test load must be kept constant.

3.2.2.4. During the test, the temperature in the test room must be maintained at between 20°C and 30°C or at a higher temperature if the manufacturer agrees.

3.2.2.5. Carry out the test continuously, without interruption.

3.3. The following procedure of load/ speed performance applies to tyres with speed category symbols "Q" and above and load capacity indices below:

+ All tyres marked with load capacity index in single 121 or less.

+ Tyres marked with load capacity index in single 122 and above and with the additional marking "C", or "LT".

- Place on the test rim a load that is:

+ 90% of the load corresponding to the load capacity index of the tyre when tested on a test drum 1.70 m ± 1% in diameter.

+ 92% of the load corresponding to the load capacity index of the tyre when tested on a test drum 2.0 m ± 1% in diameter.

- Initial test speed:  20 km/h less than that corresponding to the speed category symbol of the tyre.

- Reach the initial test speed from zero speed in 10 minutes.

- At such speed, the test occurs in 10 minutes.

- Second test speed: 10 km/h less than that corresponding to the speed category symbol of the tyre.

- At the 2^nd test speed, the test occurs in 10 minutes.

- Final test speed: corresponding to the speed category symbol of the tyre.

- At the final test speed, the test occurs in 30 minutes.

- Total test duration: 1 hour.

3.4. Procedure of tyre endurance test is specified in Table 2 of this Annex.

Table 2 - Endurance test procedure

Notes:

(1) "Special-use" tyres should be tested at a speed equal to 85%of the speed prescribed for equivalent tyres.

(2) Tyres with load index 121 or more, speed categories N or P and the additional marking "LT", or "C", shall be tested under the same procedures as specified in the above table for tyres with load index 121 or less.

ANNEX 4

VARIATION OF LOAD CAPACITY WITH SPEED IN MOTOR VEHICLES TYRES THAT ARE RADIAL-PLY AND DIAGONAL

1/ The load capacity indices refer to a single operation.

2/ Load variations are not allowed for speeds above 160 km/h. For speed category symbols "Q" and above, the speed corresponding to the speed category symbol (see Paragraph 1.3.28.) specifies the maximum speed permitted for the tyre.

ANNEX 5

TYRE-SIZE DESIGNATION AND DIMENSIONS

Table 1: Diagonal and radial tyres mounted on 5° tapered rims

(+) Tyres in diagonal construction are identified by a hyphen in place of the letter 'R' (e.g. 5.00-8).

(*) The tyre may bear the additional marking 'C' (e.g. 6.00-16C).

Table 2:  Radial-ply tyres mounted on 15° tapered rims

(*) The tyre-size designation may include the additional marking 'C' (e.g. 7 R 17.5C).

Table 3: Radial-ply and diagonal tyres for light vehicles

(+) Tyres in diagonal construction are identified by a hyphen in place of the letter 'R' (e.g. 145-10 C).

Table 4: Radial-ply and diagonal tyres for special applications

(+) Tyres in radial-ply construction are identified by the letter 'R' in place of the hyphen '-' (e.g. 15x4 1/2 R 8).

Table 5: Radial-ply and diagonal tyres for light vehicles (LT tyres)