GSO STANDARD GSO   / 
 
  
اﻟﻌﺮﺑﻴﺔ  اﻟﺨﻠﻴﺞ  ﻟﺪول اﻟﺘﻌﺎون  ﻣﺠﻠﺲ  ﻟﺪول اﻟﺘﻘﻴﻴﺲ  هﻴﺌﺔ  
GCC STANDARDIZATION ORGANIZATION (GSO)  
 
    
 ﻣﺸﺮوع:  أوﻟﻲ  
 
  
GSO 02/CD/645:2009 
 
 
واﻟﻤﻘﻄﻮرات  واﻟﺤﺎﻓﻼت  واﻟﺸﺎﺣﻨﺎت  اﻷﻏﺮاض  ﻣﺘﻌﺪدة  اﻟﺴﻴﺎرات  إﻃﺎرات   
 اﻷول اﻟﺠﺰء:  اﻹﻳﻀﺎﺣﻴﺔواﻷﺑﻌﺎد  واﻟﺒﻴﺎﻧﺎت  واﻟﺘﻤﻴﻴﺰ  اﻟﻤﺴﻤﻴﺎت   وﺿﻐﻮط  واﻷﺣﻤﺎل
اﻟﻨﻔﺦ 
Multi-Purpose Vehicles, Trucks, Buses and 
Trailers- Tyres Part 1: Nomenclature, 
Designation, Marking,  Dimensions, Load 
Capacities and Inflation Pressures  
 
 
  
 
إﻋﺪاد 
 ﻟﻘﻄﺎع اﻟﺨﻠﻴﺠﻴﺔ  اﻟﻔﺮﻋﻴﺔ  اﻟﻔﻨﻴﺔ واﻹﻃﺎراتاﻟﻠﺠﻨﺔ  اﻟﻤﺮآﺒﺎت  ﻣﻮاﺻﻔﺎت  
  
 هﺬﻩ        ﺑﺸ  واﻟﻤﻼﺣﻈ  اﻟ ﻹﺑ ﺗﻮزﻳﻌﻬ  ﺗ ﺧﻠﻴﺠﻴﺔ  ﻗﻴﺎﺳﻴﺔ  ﻟﻤﻮاﺻﻔﺔ  ﻣﺸﺮوع  اﻟﻮﺛﻴﻘﺔ
   ﺑﻌ إﻻ ﺧﻠﻴﺠﻴ  ﻗﻴﺎﺳﻴﺔ  آﻤﻮاﺻﻔﺔ  إﻟﻴﻬﺎ اﻟﺮﺟﻮع  ﻳﺠﻮز وﻻ واﻟﺘﺒﺪﻳﻞ،  ﻟﻠﺘﻐﻴﻴﺮ  ﻋﺮﺿﺔ  ﻓﺈﻧﻬﺎ ﻟﺬﻟﻚ
اﻟﻬﻴﺌﺔ إدارة ﻣﺠﻠﺲ  ﻣﻦ اﻋﺘﻤﺎدهﺎ  . GSO STANDARD GSO   / 
 
  
 
ﺗﻘﺪﻳﻢ  
 اﻟﻌﺮﺑﻴﺔ  اﻟﺨﻠﻴﺞ  ﻟﺪول اﻟﺘﻌﺎون  ﻣﺠﻠﺲ  ﻟﺪول اﻟﺘﻘﻴﻴﺲ  هﻴﺌﺔ         اﻟﻮﻃﻨﻴ  اﻷﺟﻬ  ﻋﻀ  ﻓ ﺗﻀ إﻗﻠﻴﻤﻴ  هﻴﺌ
  اﻟﺨﻠﻴﺠﻴ  اﻟﻘﻴﺎﺳ  اﻟﻤﻮاﺻ  إﻋ اﻟﻬﻴﺌ ﻣﻬ وﻣ ، اﻟﻌﺮﺑﻴ  اﻟﺨﻠ  دول ﻓ واﻟﻤﻘ  ﻟﻠﻤﻮاﺻ
 ﻣﺘﺨﺼﺼﺔ  ﻓﻨﻴﺔ ﻟﺠﺎن ﺑﻮاﺳﻄﺔ  .  
  
  ر اﻟﻔﻨﻴ اﻟﻠﺠﻨ  ﻋﻤﻞ ﺑﺮﻧﺎﻣﺞ  ﺿﻤﻦ اﻟﻌﺮﺑﻴﺔ  اﻟﺨﻠﻴﺞ  ﻟﺪول اﻟﺘﻌﺎون  ﻣﺠﻠﺲ  ﻟﺪول اﻟﺘﻘﻴﻴﺲ  هﻴﺌﺔ ﻗﺎﻣﺖ وﻗﺪ   ٢ﻗ-
١ "   واﻹﻃ  اﻟﻤﺮآﺒﺎت  ﻣﻮاﺻﻔﺎت  ﻟﻘﻄﺎع اﻟﺨﻠﻴﺠﻴﺔ  اﻟﻔﻨﻴﺔ ﻟﻠﺠﻨﺔ "   ا ﺑﺘﺤ     اﻟﺨﻠﻴﺠﻴ  اﻟﻘﻴﺎﺳ  ﻟﻤﻮاﺻ
 ٥٤٦رﻗ/ م٥٠٠٢   ،      "    واﻟﻤﻘﻄ  واﻟﺤ  واﻟﺸ  اﻷﻏ  ﻣﺘﻌ  اﻟﺴ  إﻃ
 اﻷول اﻟﺠﺰء:  و واﻷﺣﻤﺎل  اﻹﻳﻀﺎﺣﻴﺔواﻷﺑﻌﺎد  واﻟﺒﻴﺎﻧﺎت  واﻟﺘﻤﻴﻴﺰ  اﻟﻤﺴﻤﻴﺎت  اﻟﻨﻔﺦ ﺿﻐﻮط   " . ﺳ  وﻗﺎﻣ
اﻟﻤﻮاﺻﻔﺔ  هﺬﻩ ﻣﺸﺮوع  ﺑﺈﻋﺪاد  ﻋﻤﺎن  .   
  
 اﻟﻤﻮاﺻﻔﺔ  هﺬﻩ اﻋﺘﻤﺪت  آـوﻗﺪ  ) ﻗﻴﺎﺳﻴﺔ  ﻣﻮاﺻﻔﺔ/  ﻓﻨﻴﺔ ﻻﺋﺤﺔ(  ﺧﻠﻴﺠﻴﺔ     رﻗ اﻟﻬﻴﺌ إدارة ﻣﺠﻠ  اﺟﺘﻤﺎع  ﻓﻲ)           
        ( ﺑﺘ  ﻋﻘ اﻟﺬي ،      /      /       اﻟﻤﻮاﻓ  ، ه/    /      م   . اﻟﻤﻮاﺻ  ﺗُﻠﻐِ أن ﻋﻠ   رﻗ ﺔ)    /    (  
ﻣﺤﻠﻬﺎ وﺗَﺤﻞ  . 
Foreword 
 
GCC Standardization Organization (GSO ) is a regional Organization which 
consists of the National Standards Bodi es of GCC member States. One of GSO 
main functions is to issue Gulf St andards /Technical regulations through 
specialized technical  committees (TCs). 
 GSO through the technical pr ogram of committee TC No  . 2-1 " The Gulf 
technical Subcommittee for vehicles and tyres standards " has updated the GSO 
Standard No. : 645/2005 " Mu lti-Purpose Vehicles, Trucks, Buses and Trailers- 
Tyres Part 1: Nomenclature, Designa tion, Marking, Dimensions, Load 
Capacities and Inflation Pressures" . Th e Draft Standard has been prepared by 
Sultanate of Oman . 
  This standard has been approved as a Gu lf (Standard / Technical Regulation) by 
GSO Board of Directors in its meeting No.(       ),held on      /    /            H ,     /     
/              G. The approved standard will replace and supersede the GSO standard 
No. (       /      ).    
 GSO STANDARD GSO   / 
 
  
 
MULTI-PURPOSE VEHICLES, TRUCKS, 
BUSES AND TRAILERS 
TYRES PART 1: NOMENC LATURE, DESIGNATION, 
MARKING, DIMENSIONS, LOAD CAPACITIES AND 
INFLATION PRESSURES 
 
1. SCOPE AND FIELD OF APPLICATION 
 This standard is concerned with nomenclature, designation, marking, dimensions, 
load capacities and inflation pressures of new tyres for multi-purpose vehicles, 
Light Trucks, Heavy Trucks, Buses and traile rs. This standard is not applicable for 
tyre types identified by speed category less than 80km/h. 
 
2. COMPLEMENTARY REFERENCES  
2.1 GS 51/2007 "Passenger Car Tyres - Part  1: Nomenclature, Designation, Marking, 
Dimensions, Load Capacity and Inflation Pressures". 
2.2 GS 646/2009 "Multi-purpose Vehicles, Truc ks, Buses and Trailers, Part 2: Testing 
Methods". 
2.3 GS 647/2009 "Multi-purpose Vehicles, Trucks, Buses and Trailers Tyres - Part 3: 
General Requirements". 
 
3. NOMENCLATURE 
 In addition to the following definitions, the definitions mentions in GSO standards 
mention in item 2.1 are applicable. 
3.1 Pneumatic tyre 
 Circular shaped tyre made of an elastic material and enforced with steel strand 
and/or fabric and reinforced with suitab le fibres or cords and designed to be 
mounted on the rim. 
3.2 Type of pneumatic tyre  
 A category of pneumatic tyres which do not differ in such essential respects as: 
3.2.1 Manufacturer's name or trade mark. 3.2.2 Tyre size designation. 
3.2.3 Field of use as: 
3.2.3.1 Normal road-use tyres. 
3.2.3.2 Mud and snow tyres (M + S ). 
3.2.3.3 Special-use tyres (off - the - road, ...). GSO STANDARD GSO   / 
 
 3.2.3.4 Use at restricted speed. 
3.2.4 Structure 
3.2.4.1 Diagonal (bias-ply). 
3.2.4.2 Radial. 
3.2.5 Speed symbol or symbols. 
3.2.6 Load capacity index. 3.2.7 Cross section. 
3.3 Measuring rim  
 The rim on which a tyre shall be fitted for dimensional measurements. 
3.4 Test rim  
 The rim on which a tyre shall be fitted for strength, speed and endurance tests. 
3.5 Chunking  
 The breaking away of pieces of rubber from tread. 
3.6       Ply 
 A layer of rubber - coated parallel cords. 
3.7 Rim 
 A metallic support for a tyre, or a tyre and tube assembly upon which the tyre 
bead is seated. 
3.8 Ply Rating (PR)  
 Index of tyre strength, does not necessarily represent the actual number of plies in 
the tyre.  It is used to relate a given size tyre with its load and inflation pressure. 
3.9 Maximum load for a tyre 
 Load for each individual tyre from maximum load applied to the tyres installed on 
a vehicle loaded with the maximum load specified by the manufacturer. 
3.10 Load index  
 One or two numerical codes 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 tyre manufacturer. 
3.11 Speed symbol  
 A symbol indicating the speed at which the tyre can carry a load corresponding to 
its load index under the service conditions specified by the tyre manufacturer. 
 4. DESIGNATION  
 It shall be as specified in the GSO standard mentioned in 2.1, or in the 
publications of at least one of the organizat ions specified in 6.4, in addition to the 
following items: GSO STANDARD GSO   / 
 
 4.1 Tyres shall be designated according to the maximum speed using the letters 
mentioned in Table (1). 
 
 
Table (1) 
Maximum Speed and Corresponding Symbol 
for Tyre Designation 
Speed symbol F G J K L M N P Q R S T U H V 
 
Corresponding 
speed km/h   
80  
90  
100  
110  
120 
130 
140  
150 
160 
170 
180  
190  
200  
210 More 
than 
210 
 
 
4.2 Nominal rim diameter  
 In addition to the nominal diameters indicated in the GSO standard mentioned in 
2.1, the following values shall be added to this standard: 
 
Nominal rim diameter 
(mm) Figure to be used as tyre 
designation (inch) 
508 20 
533 21 
559 22 
610 24 
635 25 
318 12.5 
343 13.5 
368 14.5 
394 15.5 
419 16.5 
445 17.5 
495 19.5 
521 20.5 
572 22.5 
622 24.5 
660 26 GSO STANDARD GSO   / 
 
 711 28 
762 30 
 
 
4.3 Load index 
 In addition to the load indices mentioned in the GSO standard mentioned in 2.1 
the following values shall be added to this standard: 
 
Tyre 
load 
(Kg) Load 
index Tyre 
load 
(Kg) Load 
index Tyre 
load 
(Kg) Load 
index Tyre load 
(Kg) Load  
index 
1450 121 2575 141 4625 161 8250 181 
1500 122 2650 142 4750 162 8500 182 
1550 123 2725 143 4875 163 8750 183 
1600 124 2800 144 5000 164 9000 184 
1650 125 2900 145 5150 165 9250 185 
1700 126 3000 146 5300 166 9500 186 
1750 127 3075 147 5450 167 9750 187 
1800 128 3150 148 5600 168 10000 188 
1850 129 3250 149 5800 169 10300 189 
1900 130 3350 150 6000 170 10600 190 
1950 131 3450 151 6150 171 10900 191 
2000 132 3550 152 6300 172 11200 192 
2060 133 3650 153 6500 173 11500 193 
2120 134 3750 154 6700 174 11800 194 
2180 135 3850 155 6900 175 12150 195 
2240 136 4000 156 7100 176 12500 196 
2300 137 4125 157 7300 177 12850 197 
2360 138 4250 158 7500 178 13200 198 
2430 139 4375 159 7750 179 13600 199 
2500 140 4500 160 8000 180 14000 200 
 
 
5. MARKING GSO STANDARD GSO   / 
 
  Each tyre shall be legibly and indelibly marked, with characters of a minimum height 
of 2 mm (for words) and 4 mm (for numbers), with the following information in either 
Arabic and/or English arranged as follows: 
5.1 The manufacturer's name or trade mark; 5.2 The tyre-size designation 
5.3 The speed-category symbol (or symbols); 
5.4 The load indices; 
5.5 The word "TUBELESS" if the tyre is designed for use without an inner tube; 
5.6 The date of manufacture in the form of a group of four digits, the first two showing the 
week and the last two the year of manufacture. 
5.7 In the case of tyres which can be regrooved, the symbol "  " at least 20 mm in 
diameter, or the word "REGROOVABLE", moulded into or on to each sidewall; 
5.8 The suffix "C" or "LT" after the rim diameter marking, if applicable. 
5.9 Country of Production 
5.10 Tread Wear Indicator 
 
6. DIMENSIONS, LOAD CAPACITIES AND INFLATION PRESSURES  
6.1 Section width  
6.1.1 The section width shall be obtained by means of the following formula, (which 
applies to tyres with a metric size designation.  For tyres with a code size 
designation, item 6.3 applies). 
 
S = S 1 + K (A – A 1) 
 
Where: 
S = is the section width expressed in millimetres and measured on the measuring 
rim. 
S1 =  is the nominal section width in millimetres, as shown on the sidewall of the 
tyre in the tyre designation as prescribed. 
A = is the width of the measuring rim in millimetres, as specified by the 
manufacturer. 
A1=  is the width of the theoretical rim in millimetres. 
A1  shall be taken equal to S 1 multiplied by the factor x as prescribed by the tyre 
manufacturer and K shall be taken equal to 0.4. 
6.1.2 The overall width of a tyre may be less than the section width determined in 
accordance with item 6.1.1 
6.1.3 The section width may exceed by 4% in case of radial ply tyres and by 8% in case 
of diagonal (bias-ply) tyres.  However, for tyres of a section width exceeding 305 GSO STANDARD GSO   / 
 
 mm intended for dual mounting (twinning), the nominal value shall not be 
exceeded by more than 2% for radial ply tyres with nominal aspect ratio higher 
than 60 or 4% for diagonal (bias-ply) tyres. 
6.2 Outer diameter 
6.2.1  The outer diameter of a tyre shall be obtained by means of the following formula, 
(which appliels to tyres with a metric size designation, for tyres with a code size 
designation, item 6.3 applies).  
                                      D = d 1 + 0.02 × (S 1× R a) 
                                                                                            
Where: 
D  is the outer diameter expressed in millimetres. 
d1  is the conventioal number denoting the nominal diameter of the rim (in mm). 
S1  is the nominal section width in millimetres. 
Ra  is the nominal aspect ratio,  
6.2.2 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 H = 0.5 (D-d) 
 
  Coefficients "a" and "b" are respectively: 
 
  Coefficient "a" = 0.97 
 
Coefficient "b"  Radial Diagonal  
normal use tyres 1.04 1.07 
for special use tyres 1.06 1.09 
 
     
          
 
6.3 For the existing types of tyres whose designation is given in publications 
mentioned in 6.4, the section width and the outer diameter shall be as mentioned in 
those publications. 
6.4 Dimensions load, capacities and inflation pressures shall be in accordance with 
what is mentioned in current publications, at the date of manufacture of the tyre or 
any later date, of at least one of the following organizations: 
6.4.1 "The Tyre and Rim Association TRA in USA". 
6.4.2 "The European Tyre and Rim Technical Organization ETRTO". 
6.4.3 "Japan Automobile Tyre Manufacturers Association JATMA". 6.4.4 "Deutsches Institut Fur Normung (DIN)". 
6.4.5 "British Standards Institution". GSO STANDARD GSO   / 
 
 6.4.6 "Scandinavian Tyre and Rim Organization STRO". 
6.4.7 "The Tyre and Rim Organization of Australia". 
6.4.8     "Association Francaise de Normalisation AFNOR"-