Draft Kenya Standarddks 2052: 2007

DRAFT KENYA STANDARDDKS 2052: 2007

DRAFT KENYA STANDARD DKS 2052:2007

New pneumatic tyresfor Commercial vehicles — Specification

TECHNICAL COMMITTEE REPRESENTATION

The following organizations were represented on the Technical Committee:

Automobile Association of Kenya

Applied Management and Technical Solutions Ltd

General Motors East Africa Ltd

Good Year Kenya

Kajulu holdings Ltd

Kingsway Tyres Ltd

Michelin Tyre

Ministry of Roads and Public Works

Nyanza Petroleum Dealers

Pirelli Europe (SA)

Sameer Africa Ltd

Treadsetters Tyres Ltd

Kenya Bureau of Standards — Secretariat

REVISION OF KENYA STANDARDS

In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are welcome.

Copyright: Users are reminded that by virtue of section 6 of the Copyright Act, Cap. 130 of the Laws of Kenya, copyright subsists in all Kenya Standards and except as provided under section 7 of this Act, no Kenya Standard produced by Kenya Bureau of Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the Managing Director.

ISBN xxxxxxxxx

New pneumatic tyresfor Commercial vehicles — Specification

KENYA BUREAU OF STANDARDS (KEBS)

Head Office: P.O. Box 54974, Nairobi-00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020) 604031

E-Mail: , Web:

Coast RegionLake Region North Valley Region

P.O. Box 99376, Mombasa-80100P.O. Box 2949, Kisumu-40100 P.O. Box 2138, Nakuru-20100

Tel.: (+254 041) 229563, 230939/40Tel.: (+254 057) 23549, 22396 Tel.: (+254 051) 210553, 210555

Fax: (+254 041) 229448Fax: (+254 057) 21814

Foreword

This Kenya Standard was prepared by the Technical Committee on Tyres, Rims and Valves under the guidance of the Mechanical Engineering Industry Standards Committee, and it is in accordance with the procedures of the Bureau.

Tyres play a vital role in vehicle performance, handling and safety. They carry the full weight of the vehicle, while at the same time providing the entire grip for acceleration, steering and braking while the importance of good tyres is often overlooked or taken for granted. Tyre faults are noted in half of all fatal crashes where vehicle defects are a contributing factor.

Good tyres will hold the vehicle securely on the road, allowing it to stop, start and manoeuvre safely. Worn out, incorrectly inflated or unsuitable tyres may not. The tyres should be in good condition, properly maintained and appropriate for the vehicle.

It is important to have tyres fitted to the car that comply with an approved standard. Tyres should undergo speed, endurance and strength tests to comply with a standard. The tyre retailer should be able to confirm that any tyres he/she sales meet the approved standard.

The purpose of preparing this standard is therefore to assist both the manufacturers and the consumers of tyres.

During the preparation of this standard, reference was made to the following document:

Federal Motor Vehicle Safety Standard No. 119 of USA.

E/ECE/324 Rev.1/Add.53/Rev.2 E/ECE/TRANS/505, Agreement concerning the adoption of uniform technical prescriptions for wheeled vehicles, equipment and parts which can be fitted and/or be used on wheeled vehicles and the conditions for reciprocal recognition of approvals granted on the basis of these prescriptions, Addendum 53: Standard No. 54, Revision 2: Uniform provisions concerning the approval of pneumatic tyres for commercial vehicles and their trailers.

Acknowledgement is hereby made for the assistance derived from this source.

DKS 2052: 2007

New pneumatic tyres for Commercial vehicles — Specification

1Scope

1.1 This Standard covers new pneumatic tyres designed primarily, but not only, for commercial vehicles and their trailers.

1.2 The standard does not apply to tyre types identified by speed category symbols corresponding to speeds below 80km/h.

2 Definitions

For the purposes of this standard the following definitions as well as those in DKS 76 apply (Also see figure 1).

2.1

normal tyre

a tyre intended for normal, everyday, on-road use;

2.2

special use tyre

a tyre intended for mixed use both on- and off-road or for other special duty

Figure 1 — Explanatory figure

2.3

snow tyre

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.

2.4

lower sidewall

the area included between the line of maximum section width of the tyre and the area designed to be covered by the rim flange. However, in case of tyres identified by the "tyre to rim fitment configuration" symbol "A", it means the area of the tyre, which is seating on the rim.

2.5

nominal aspect ratio (Ra)

one hundred times the number obtained by dividing the number expressing the section height by the number expressing the nominal section width, both dimensions expressed in the same units;

2.6

load-capacity index

one or two numbers which indicate the load the tyre can carry in single or in single and dual operation at the speed corresponding to the associated speed category and when operated in conformity with the requirements governing utilization specified by the manufacturer. A type of pneumatic tyre can have either one or two sets of load capacity indices depending on whether or not the provisions of 5.3.5 are applied. These indices and their corresponding loads are given in table 3 and table 4.

2.7

tyre-size designation

a designation showing:

2.7.1

the nominal section width (S1). This width is expressed inmm, except in the case of types of tyre for which the size designation is given in the tables in annexA to this standard

2.7.2

nominal aspect ratio except in the case of certain types of tyre for which the size designation is given in the tables in annex A to this standard or, depending on the tyre design type, the nominal outer diameter expressed in mm;

2.7.3

conventional number "d" (the "d" symbol) denoting the nominal diameter of the rim and corresponding to its diameter expressed either in codes (number below 100) or in millimetres (numbers above 100). Numbers corresponding to both types of measurement may be used together in the designation;

2.7.3.1The values of the "d" symbols expressed in millimetres are given in table 1

Table 1 — Values of “d” symbols

Nominal rim diameter code
("d" symbol) / Value of the "d" symbol
expressed in mm
8 / 203
9 / 229
10 / 254
11 / 279
12 / 305
13 / 330
14 / 356
15 / 381
16 / 406
17 / 432
18 / 457
19 / 482
20 / 508
21 / 533
22 / 559
24 / 610
25 / 635
14.5 / 368
16.5 / 419
17.5 / 445
19.5 / 495
20.5 / 521
22.5 / 572
24.5 / 622
26 / 660
28 / 711
30 / 762

2.7.3.2An indication of the tyre to rim fitment configuration when it differs from the standard configuration and is not already expressed by the symbol "d" denoting the nominal rim diameter code.

2.8

theoretical rim

a rim whose width would be equal to xtimes the nominal section width of a tyre; the value of x shall be specified by the manufacturer of the type

2.9

commercial vehicles

are

a) vehicles used for the carriage of passengers, comprising more than eight seats in addition to the driver's seat, and having a maximum mass not exceeding 5 tons.

b) vehicles used for the carriage of passengers, comprising more than eight seats in addition to the driver's seat, and having a maximum mass exceeding 5 tons

c) power-driven vehicles having at least four wheels and used for the carriage of goods

d) trailers (including semi trailers) with a maximum mass exceeding 3.5 tons

3Speed categories and maximum load rating

3.1 Speed categories

The speed categories are as shown in the Table 1

3.2Load-capacity variation with speed

3.2.1 The maximum load rating

The maximum load rating shall be the value associated with the load capacity index of the tyre as given in table 3.

3.2.2 Load-capacity variation with speed

When used at speeds different from that conforming to its nominal-speed-category symbol, a pneumatic tyre shall withstand the load variations given in table 4. The load variations do not apply in the case of the additional load capacity symbol and speed category obtained when the provisions of 5.3.5 are applied.

Table 3—Load-capacity indices

Li / Kg / Li / Kg / Li / Kg / Li / Kg
60 / 250 / 100 / 800 / 140 / 2 500 / 180 / 8 000
61 / 257 / 101 / 825 / 141 / 2 575 / 181 / 8 250
62 / 265 / 102 / 850 / 142 / 2 650 / 182 / 8 500
62 / 272 / 103 / 875 / 143 / 2 725 / 183 / 8 750
64 / 280 / 104 / 900 / 144 / 2 800 / 184 / 9 000
65 / 290 / 105 / 925 / 145 / 2 900 / 185 / 9 250
66 / 300 / 106 / 950 / 146 / 3 000 / 186 / 9 500
67 / 307 / 107 / 975 / 147 / 3 075 / 187 / 9 750
68 / 315 / 108 / 1 000 / 148 / 3 150 / 188 / 10 000
69 / 325 / 109 / 1 030 / 149 / 3 250 / 189 / 10 300
70 / 335 / 110 / 1 060 / 150 / 3 350 / 190 / 10 600
71 / 345 / 111 / 1 090 / 151 / 3 450 / 191 / 10 900
72 / 355 / 112 / 1 120 / 152 / 3 550 / 192 / 11 200
73 / 365 / 113 / 1 150 / 153 / 3 650 / 193 / 11 500
74 / 375 / 114 / 1 180 / 154 / 3 750 / 194 / 11 800
75 / 387 / 115 / 1 215 / 155 / 3 875 / 195 / 12 150
76 / 400 / 116 / 1 250 / 156 / 4 000 / 196 / 12 500
77 / 412 / 117 / 1 285 / 157 / 4 125 / 197 / 12 850
78 / 425 / 118 / 1 320 / 158 / 4 250 / 198 / 13 200
79 / 437 / 119 / 1 360 / 159 / 4 375 / 199 / 13 600
80 / 450 / 120 / 1 400 / 160 / 4 500 / 200 / 14 000
81 / 462 / 121 / 1 450 / 161 / 4 625
82 / 475 / 122 / 1 500 / 162 / 4 750
83 / 487 / 123 / 1 550 / 163 / 4 875
84 / 500 / 124 / 1 600 / 164 / 5 000
85 / 515 / 125 / 1 650 / 165 / 5 150
86 / 530 / 126 / 1 700 / 166 / 5 300
87 / 545 / 127 / 1 750 / 167 / 5 450
88 / 560 / 128 / 1 800 / 168 / 5 600
89 / 580 / 129 / 1 850 / 169 / 5 800
90 / 600 / 130 / 1 900 / 170 / 6 000
91 / 615 / 131 / 1 950 / 171 / 6 150
92 / 630 / 132 / 2 000 / 172 / 6 300
93 / 650 / 133 / 2 060 / 173 / 6 500
94 / 670 / 134 / 2 120 / 174 / 6 700
95 / 690 / 135 / 2 180 / 175 / 6 900
96 / 710 / 136 / 2 240 / 176 / 7 100
97 / 730 / 137 / 2 300 / 177 / 7 300
98 / 750 / 138 / 2 360 / 178 / 7 500
99 / 775 / 139 / 2 430 / 179 / 7 750
NOTE Li stands for Load index

Table 4 — Variation of load capacity with speed commercial vehicles tyres

Radial and diagonal

Variation of load capacity (per cent)
Speed
(km/h) / All load indices / Load indices
≥122 / Load indices ≤121
Speed category symbol / Speed category symbol / Speed category symbol
F / G / J / K / L / M / L / M / N / P
0 / +150 / +150 / +150 / +150 / +150 / +150 / +110 / +110 / +110 / +110
5 / +110 / +110 / +110 / +110 / +110 / +110 / +90 / +90 / +90 / +90
10 / +80 / +80 / +80 / +80 / +80 / +80 / +75 / +75 / +75 / +75
15 / +65 / +65 / +65 / +65 / +65 / +65 / +60 / +60 / +60 / +60
20 / +50 / +50 / +50 / +50 / +50 / +50 / +50 / +50 / +50 / +50
25 / +35 / +35 / +35 / +35 / +35 / +35 / +42 / +42 / +42 / +42
30 / +25 / +25 / +25 / +25 / +25 / +25 / +35 / +35 / +35 / +35
35 / +19 / +19 / +19 / +19 / +19 / +19 / +29 / +29 / +29 / +29
40 / +15 / +15 / +15 / +15 / +15 / +15 / +25 / +25 / +25 / +25
45 / +13 / +13 / +13 / +13 / +13 / +13 / +22 / +22 / +22 / +22
50 / +12 / +12 / +12 / +12 / +12 / +12 / +20 / +20 / +20 / +20
55 / +11 / +11 / +11 / +11 / +11 / +11 / +17.5 / +17.5 / +17.5 / +17.5
60 / +10 / +10 / +10 / +10 / +10 / +10 / +15.0 / +15.0 / +15.0 / +15.0
65 / +7.5 / +8.5 / +8.5 / +8.5 / +8.5 / +8.5 / +13.5 / +13.5 / +13.5 / +13.5
70 / +5.0 / +7.0 / +7.0 / +7.0 / +7.0 / +7.0 / +12.5 / +12.5 / +12.5 / +12.5
75 / +2.5 / +5.5 / +5.5 / +5.5 / +5.5 / +5.5 / +11.0 / +11.0 / +11.0 / +11.0
80 / 0 / +4.0 / +4.0 / +4.0 / +4.0 / +4.0 / +10.0 / +10.0 / +10.0 / +10.0
85 / -3 / +2.0 / +3.0 / +3.0 / +3.0 / +3.0 / +8.5 / +8.5 / +8.5 / +8.5
90 / -6 / 0 / +2.0 / +2.0 / +2.0 / +2.0 / +7.5 / +7.5 / +7.5 / +7.5
95 / -10 / -2.5 / +1.0 / +1.0 / +1.0 / +1.0 / +6.5 / +6.5 / +6.5 / +6.5
100 / -15 / -5 / 0 / 0 / 0 / 0 / +5.0 / +5.0 / +5.0 / +5.0
105 / -8 / -2 / 0 / 0 / 0 / +3.75 / +3.75 / +3.75 / +3.75
110 / -13 / -4 / 0 / 0 / 0 / +2.5 / +2.5 / +2.5 / +2.5
115 / -7 / -3 / 0 / 0 / +1.25 / +1.25 / +1.25 / +1.25
120 / -12 / -7 / 0 / 0 / 0 / 0 / 0 / 0
125 / 0 / -2.5 / 0 / 0 / 0
130 / 0 / -5.0 / 0 / 0 / 0
135 / -7.5 / -2.5 / 0 / 0
140 / -10 / -5 / 0 / 0
145 / -7.5 / -2.5 / 0
150 / -10.0 / -5.0 / 0
155 / -7.5 / -2.5
160 / -10.0 / -5.0
NOTE 1 The load capacity indices refer to a single operation.
NOTE 2 Load variations are not allowed for speeds above 160 km/h. For speed category symbols "Q" and above the speed category corresponding to the speed category symbol (see table 2) specifies the maximum speed permitted for the tyre.

4Dimensions of tyres

4.1 Each manufacturer of tyres shall ensure that a listing of the sizes of commercial vehicle tyres and rims that may be used with each tyre that he/she produces is provided. The listing shall be in one of the following forms:

(a) Listed by manufacturer name or brand name in a document furnished to dealers of the manufacturer’s tyres, and to the relevant government authority upon request.

(b) Contained in publications identified as commercial vehicle tyres, current at the date of manufacture of the tyre or any later date, of at least one of the following organizations:

The Tire and Rim Association (TRA)

The European Tyre and Rim Technical Organisation (ETRTO)

Japan Automobile Tire Manufacturers’ Association, Inc. (JATMA)

4.2 Information contained in any publication specified in 4.1 (b) which lists general categories of tyres and rims by size designation, type of construction and/or intended use, shall be considered to be manufacturer’s information in accordance with 4.1 for the listed tires and rims, unless the publication itself or specific information provided according to 4.1 (a) indicates otherwise.

NOTE Examples of the tyre size, designation and dimensions are given in Annex A.

4.3Section width of a tyre

4.3.1The section width shall be obtained by means of the following formula:

S = S1 + K (A - A1),

where:

Sis the "section width" expressed in millimetres and measured on the measuring rim;

S1is "the nominal section width" in millimetres, as shown on the sidewall of the tyre in the tyre designation as prescribed;

Ais the width of the measuring rim in millimetres, as shown by the manufacturer in the descriptive note; and

A1is the width of the theoretical rim in millimetres.

A1 shall be taken to equal S1 multiplied by the factor x as specified by the manufacturer, and K shall be taken to equal 0.4.

4.3.2However, for the existing types of tyres whose designation is given in the tables in annex A to this standard, the section width shall be deemed to be that given opposite the tyre designation in those tables. However, for tyres identified by the "tyre to rim fitment configuration” symbol "A", K shall be taken to equal 0.6.

4.4Outer diameter of a tyre

4.4.1The outer diameter of a tyre shall be obtained by means of the following formula:

D = d + 2H

where:

Dis the outer diameter expressed in millimetres;

dis the conventional number defined in paragraph2.7.3, expressed in millimetres;

S1is the nominal section width in millimetres;

Rais the nominal aspect ratio;

His the nominal section height in millimetres and is equal to S1 x 0.01 Ra.

All as in the tyre designation shown on the sidewall of the tyre in conformity with the requirements of 9.4.

4.4.2However, for the existing types of tyres whose designation is given in the tables in annex A to this standard, the outer diameter shall be deemed to be that given opposite the tyre designation in those tables. However, for tyres identified by the "tyre to rim fitment configuration" symbol "A", the outer diameter shall be that specified in the tyre size designation as shown on the sidewall of the tyre.

5 Test requirements

5.1Physical dimensions

The dimensions of pneumatic tyres shall be measured by the procedure described in annex B to this standard.

5.1.1Tyre section width specifications

5.1.1.The overall width of a tyre may be less than the section width or widths determined 4.1.1.

5.1.2It may exceed that value by 4 per cent in case of radial-ply tyres and by 8 per cent in the case of diagonal (bias-ply) tyres. However, for tyres with nominal section width exceeding 305mm intended for dual mounting (twinning), the value determined pursuant to 4.1.1 shall not be exceeded by more than 2per cent for radial-ply tyres with nominal aspect ratio higher than 60, or 4per cent for diagonal (bias-ply) tyres.

5.1.3However, for tyres identified by the "tyre to rim fitment configuration" (see 9.1.11) symbol "A", the overall width of the tyre, in the lower area of the tyre, equals the nominal width of the rim on which the tyre is mounted, as shown by the manufacturer in the descriptive note, increased by 27mm.

5.1.2Tyre outer diameter specifications

The outer diameter of a tyre must not be outside the values Dmin and Dmax obtained from the following formulae:

Dmin = d + (2H x a)

Dmax = d + (2H x b)

where:

a) For sizes listed in annex A and for tyres identified by the "tyre to rim fitment configuration" (see9.1.11) symbol "A", the nominal section height H is equal to:

H = 0.5 (D-d) - for references see 4.2.1

b) For other sizes, not listed in annex A

"H" and "d" are as defined in 4.2.1.

c) Coefficients "a" and "b" are respectively:

i)Coefficient "a" = .97

ii) Coefficient "b"RadialDiagonal

for normal use tyres 1.04 1.07

for special use tyres 1.06 1.09

d) For snow tyres the outer diameter (Dmax) established in conformity with the above may be exceeded by 1 per cent.

5.2 Tyre strength tests

When tested in accordance with Annex C, a tyre’s average breaking energy value shall be not less than the value given in Table 5 for that tyre’s size and load range.

Table 5 — Minimum static breaking energy (joules)

Tyre category / Tyre characteristic / All 305 mm diameter rim or smaller rim size / LT, 445 mm diameter rim or smaller rim tubeless size / Tube type / Tubeless / Tube type / Tubeless
Plunger diameter (mm) / 19 / 19 / 32 / 38
F / 406 / 664 / 1,785 / 1,412 / - / -
G / - / 712 / - / - / 2,282 / 1,694
H / - / 768 / - / - / 2,598 / 2,090
J / - / - / - / - / 2,824 / 2,203
L / - / - / - / - / 3,050 / -
M / - / - / - / - / 3,220 / -
N / - / - / - / - / 3,389 / -
NOTE For rayon cord tyres, applicable energy values are 60% of those in the table.

5.3 Load/speed endurance test

5.3.1Each type of pneumatic tyre shall undergo at least one load/speed endurance tests carried out by the procedure described in annexD to this standard.

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

5.3.3 The outer diameter of the tyre, measured six hours after the load/speed endurance test, must not differ by more than 3.5percent from the outer diameter as measured before the test.

5.3.4Where application is made for the approval of a type of pneumatic tyre for the load/speed combinations given in table 4, the endurance test in 5.3.1 above need not be carried out for load and speed values other than the nominal values.

5.3.5Where application is made for the approval of a type of pneumatic tyre which has a load/speed combination in addition to the one that is subject to the variation of load with speed given in table 4, the endurance test prescribed in 5.3.1 shall also be carried out on a second tyre of the same type at the additional load/speed combination.

6 Application for approval

6.1 The application for approval of a type of pneumatic tyre shall be submitted by the holder of the manufacturer's name or trademark or by his duly accredited representative. It shall specify:

6.1.1The tyre-size designation as defined in paragraph 2.7 of this standard;

6.1.2The manufacturer's name or trade mark;

6.1.3The category of use (normal or special or snow);

6.1.4Structure: diagonal (bias ply) or radial;

6.1.5The speed category;

6.1.6The load-capacity indices;

6.1.7Whether the tyre is intended to be used with or without an inner tube;

6.1.8The overall dimensions: overall section width and outer diameter;

6.1.9The factor "x" referred to in 2.8 of this standard.

6.1.10The rims on which the tyre can be mounted;

6.1.11The measuring rim and test rim;

6.1.12The measuring pressure and test pressure index;

6.1.13The additional load/speed combinations in cases where 5.3.5 is applied.

6.2The application for approval shall be accompanied (all in triplicate) by a sketch, or a representative photograph, which identify the tyre tread pattern and a sketch of the envelope of the inflated tyre mounted on the measuring rim showing the relevant dimensions (see 4.1 and 4.2) of the type submitted for approval. It shall also be accompanied either by the test report issued by the approved test laboratory or by one or two samples of the tyre type, at the discretion of the competent authority. Drawings or photographs of the side wall and tread of the tyre shall be submitted once production has been established, no later than one year after the date of issue of the type approval.

6.3The competent authority shall verify the existence of satisfactory arrangements for ensuring effective control of the conformity of production before type approval is granted.

6.4Where a tyre manufacturer submits application for type approval for a range of tyres, it is not considered necessary to carry out a load/speed test on every type of tyre in the range. Worst case selection may be made at the discretion of the approval authority.

7 Approval

7.1If the type of pneumatic tyre submitted for approval in pursuance of this standard meets the requirements of clause 4 and 5, approval of that type of tyre shall be granted.

NOTE Exceptions may be given for tyres (see 9.2)

Draft Kenya Standarddks 2052: 2007

REVISION OF KENYA STANDARDS

Foreword

New pneumatic tyres for Commercial vehicles — Specification

2 Definitions

Figure 1 — Explanatory figure

Table 1 — Values of “d” symbols

3Speed categories and maximum load rating

Table 2 — Speed Categories

Table 3—Load-capacity indices

Radial and diagonal