هيئت التقييس لذول مجلس التعبون لذول الخليج العربيت 
GCC STANDARDIZATION ORGANIZATION (GSO)  
 
 
 
 
 
هشزوع:  ًهبئً 
 
 
 
GSO2/1/FDS/GSO  645:2013 
 
 
إطبراث السيبراث متعذدة الأغراض والشبحنبث والحبفلاث والمقطوراث
الجزء الأول : المسميبث والتمييز والبيبنبث الإيضبحيت والأبعبد والأحمبل 
وضغوط النفخ 
Multi -Purpose Vehicles,  Trucks, Buses and  
Trailers - Tyres  Part 1: Nomenclature,  
Designation,  Marking, Dimensions, Load  
Capacities and Inflation Pressures 
 
 
 
 
 
إعذاد 
اللجٌت الفٌٍت الفزعٍت الخلٍجٍت لقطبع هىاصفبث الوزكببث والإطبراث 
 
هذٍ الىثٍقت هشزوع لوىاصفت قٍبسٍت خلٍجٍت حن حىسٌعهب لإبذاء الزأي والولاحظبث بشأًهب، 
لذلك فإًهب عزضت للخغٍٍز والخبذٌل، ولا ٌجىس الزجىع إلٍهب كوىاصفت قٍبسٍت خلٍجٍت إلا بعذ 
اعخوبدهب هي هجلس إدارة الهٍئت.    
 
تقذيم
هٍئت الخقٍٍس لذول هجلس الخعبوى لذول الخلٍج العزبٍت هٍئت إقلٍوٍت حضن فً عضىٌخهب الأجهشة الىطٌٍت 
للوىاصفبث والوقبٌٍس فً دول الخلٍج العزبٍت ، وهي ههبم الهٍئت إعذاد الوىاصفبث القٍبسٍت الخلٍجٍت 
بىاسطت لجبى فٌٍت هخخصصت .  
 
وقذ قبهج هٍئت الخقٍٍس لذول هجلس الخعبوى لذول الخلٍج العزبٍت ضوي بزًبهج عول اللجٌت الفٌٍت رقن 2-
1 "  للجٌت الفٌٍت الخلٍجٍت لقطبع هىاصفبث الوزكببث والإطبراث"  بخحذٌث الوىاصفت القٍبسٍت الخلٍجٍت  
رقن 645 / 2005م،      " إطبراث السٍبراث هخعذدة الأغزاض والشبحٌبث والحبفلاث والوقطىراث 
الجشء الأول : الوسوٍبث والخوٍٍش والبٍبًبث الإٌضبحٍتوالأبعبد والأحوبل وضغىط الٌفخ " .وقبهج سلطٌت  
عوبى بإعذاد هشزوع هذٍ الوىاصفت.   
 
وقذ اعخوذث هذٍ الوىاصفت كـ(هىاصفت قٍبسٍت  / لائحت فٌٍت) خلٍجٍت فً اجخوبع هجلس إدارة الهٍئت رقن  (           
) ، الذي عقذ بخبرٌخ      /      /      هـ ، الوىافق    /    /     م. على أى حُلغًِ الوىاصفت رقن (    /     ) 
وحَحل هحلهب.  
Foreword 
 
GCC Standardization Organization (GSO) is a regional Organization which 
consists of the National Standards Bodies of GCC member States. One of GSO 
main functions is to issue Gulf Standards /Technical regulatio ns through 
specialized technical committees (TCs).  
 
GSO through the technical program of committee TC No . 2-1 " The Gulf 
technical Subcommittee for vehicles and tyres standards " has updated the GSO 
Standard No. : 645/2005 " Multi -Purpose Vehicles, Trucks,  Buses and Trailers - 
Tyres Part 1: Nomenclature, Designation, Marking, Dimensions, Load 
Capacities and Inflation Pressures" . The Draft Standard has been prepared by 
Sultanate of Oman . 
  
This standard has been approved as a Gulf (Standard / Technical Regul ation)  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  /   
 
1 
  
 
MULTI -PURPOSE VEHICLES, TRUCKS,  
BUSES  AND TRAILERS  
TYRES PART 1: NOMENCLATURE, 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 infl ation pressures of new tyres for multi -purpose vehicles, 
Light Trucks, Heavy Trucks , Buses  and trailers. 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 Ca r Tyres - Part 1: Nomenclature, Designation, Marking, 
Dimensions, Load Capacity and Inflation Pressures".  
2.2 GS 646 /2009  "Multi -purpose Vehicles, Trucks, 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 materi al and enforced with steel strand 
and/or fabric and reinforced with suitable 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  Manufactu rer'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, snow ... ). GSO STANDARD  GSO  /   
 
2 
 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 t yre 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 dua l operation at the speed corresponding to the associated speed 
category and when operated in conformity with the requi rements governing 
utilization specified by the tyre manufacturer.  
3.11 Speed symbol  
 A symbol indicating the speed at which the tyre can c arry 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 organizations specifi ed in 6.4, in addition to the 
following items:  GSO STANDARD  GSO  /   
 
3 
 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 sha ll 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 GSO STANDARD  GSO  /   
 
4 
 660 26 
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 
 
 GSO STANDARD  GSO  /   
 
5 
 5. MARKING  
 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, th e 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 " É" at least 20 mm in  
diameter, or the word "REGROOVABLE", moulded into or on to each sidewall;  
5.8 The suffix "C" and the pr efix or suffix  "LT"  in the tyre size designation  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 o btained 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 – A1) 
 
Where:  
S = is the section width expressed in millimetres and measured on th e 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 
accordan ce with item 6.1.1  GSO STANDARD  GSO  /   
 
6 
 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 
mm intended for dual mounting (twinning), the nominal value shall n ot 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 = d1 + 0.02 (S1 – Ra) 
                                                                                            
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 no minal section width in millimetres.  
Ra  is the nominal aspect ratio,  
6.2.2  The outer diameter of a tyre shall no t differ from the value " D" by more than ± 
1.5% in the case of tyres used on the road, nor by more than +5% and not less than 
-2% in the case of tyres for special use such as off -road use.  
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 T yre Manufacturers Associ ation JATMA".  
6.4.4  "Deutsches Institut Fur Normung (DIN)".  
6.4.5  "British Standards Institution".  
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 AF NOR" -