هيئة التقييس لدول مجلس التعاون لدول الخليج العربية  
GCC STANDARDIZATION ORGANIZATION (GSO)  
 
 
مشروع مواصفة نهائي 
Final Draft of  Standard FDS  
  
 
 
 
إعداد اللجنةالفنية الفرعية  الخليجية رقم TC 02/SC 01 
 
Prepared by GSO Technical Sub -Committee No. TC 02/SC 01  
 
  
 
GSO 02  /01/FDS/  645:2017  
 
 
 
 
إطارات المركبات التجارية  الجزء الثاني: طرق الاختبار  
Tyres for Commercial Vehicles  Part 2: Methods of Test  
 
 
 
 
   ICS:  43.020  
هذه الوثيقة مشروعلمواصفة قياسية  خليجية تم توزيعها 
لإبداء الرأي والملحوظات بشأنها ، لذلك فإنها عرضة 
للتغيير والتبديل ، ولا يجوز الرجوع إليها كمواصفة 
قياسية  خليجية إلا بعد اعتمادها من الهيئة. This document is  a draft Gulf Standard  
circulated for comments. It is, therefore, 
subject to alteration and modification 
and may not be referred to as a Gulf 
Standard  until approved by GSO.  GSO 646:2017            GSO STANDARD 
 
 
 new paragraphs  
  modified paragraphs  
  deleted paragraphs  2 تقديم 
 
هيئةةة التقيةةي  لةةدو  مجلةة  التعةةاو   لةةدو  الخلةةي  العربيةةة هيئةةة إقليميةةة تضةةم فةة  عضةةويتها أجهةة   التقيةةي  
الوطنيةةة فةة  الةةدو  الأعضةةاء ، ومةةن مهةةا  الهيئةةة إعةةداد المواصةةفات القياسةةية واللةةوا ا الفنيةةة الخليجيةةة 
بواسطة لجا  فنية متخصصة . 
قةةةةر  المجلةةةة  الفنةةةة  لهيئةةةةة التقيةةةةي  لةةةةدو  مجلةةةة  التعةةةةاو  لةةةةدو  الخلةةةةي  العربيةةةةة فةةةة  اجتماعةةةة   قةةةةةةم ( ) 
الةةةةةةةةةةذي عقةةةةةةةةةةد بتةةةةةةةةةةا ي ......./......./....... هةةةةةةةةةةة ،الموافةةةةةةةةةة. ......./...../.......    اعتمةةةةةةةةةةاد تحةةةةةةةةةةدي  
المواصةةةةفة القياسةةةةية الخليجيةةةةة  قةةةةم  GSO 646:2017  "إطةةةةا ات المركبةةةةات التجا يةةةةة الجةةةة ء ال ةةةةان 
طةةةةةرت الاختبةةةةةا  " التةةةةة  تةةةةةم د اسةةةةةتها و إعةةةةةدادها ضةةةةةمن برنةةةةةام  عمةةةةةل اللجنةةةةةة الفنيةةةةةة الفرعيةةةةةة الخليجيةةةةةة 
 قةةةةةم TC 02/SC01   " اللجنةةةةةة الفنيةةةةةة الفرعيةةةةةة الخليجيةةةةةة لمواصةةةةةفات المركبةةةةةات والإطةةةةةا ات " 
المد جة ف  خطة دولة الكويت . 
على أ  تلغ  المواصفة القياسية الخليجية  قم GSO 646:1996  و تحل محلها 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
    
 
 
 GSO 646:2017            GSO STANDARD 
 
 
 new paragraphs  
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Tyres for Commercial Vehicles  Part 2: Methods of Test 
 
 
 
1- SCOPE AND FIELD OF APPLICATION  
 
 This standard is concerned with methods of testing new tyres for commercial 
vehicles ( Light Trucks, Heavy Trucks, Buses and trailers ).This standard is not 
applicable for tyre types identified by speed category less than 80  km/h. It is 
also not applicable to motor cycle, road equipment or agricultural 
equipment tyres.  
 
2- COMPLEMENTARY REFERENCES  
 
2.1 GSO 645/2017 “Multi -purpose Vehicles, Trucks, Buses and Trailers, Part    
       1: “Nomenclature, Designation, Marking, Dimensions, Load  
       Capacities and Inflation Pressures”  
 
2.2        GSO 647/2017 “ Tyres for Commercial Vehicles , Part   
       3: General Requirements".  
 
3- VISUAL INSPECTION  
 
3.1            Tyres shall be visually inspected to check for the absence of any cracks or  
cuts in the tread or on either sidewall.  Check the tyre for any uneven shape 
between the sidewalls, by rotating the tyre on a flat surface  
 
3.2 The tyre shall be visually inspected for all the required marking specified in 
GSO 645/2017 Regulation (see item 2.1).  
 
4-          DIMENSIONS MEASUREMENT  
 
4.1        Tyre W idth 
 
4.1.1  The tyre shall be mounted on the measuring rim and inflated to the pressure 
specified by the manufacturer.   
 
4.1.2  Prior to measuring, it shall be allowed to stand for 24 h. at room temperature.   
 
4.1.3  The pressure shall be adjusted to the specified value  mentioned in item 4.1.1 . 
 
4.1.4  The tyre width at its maximum point, excluding elevations due to labelling or 
decoration and other edges band by a caliper, shall then be calipered at six 
different points equally spaced around the circumference.   
 
4.1.5  The highest measurements shall be taken as the tyre's width.  
 GSO 646:2017            GSO STANDARD 
 
 
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  deleted paragraphs  4 4.2       Overall D iameter  
The maximum outer circumfe rence shall be measured with a steel tape and 
then divided by 3.1416 in order to  calculate the overall diameter.  
 
5-       STRENGTH TEST  
 
5.1             Preparation of Tyre 
 
5.1.1 The tyre shall be mounted on the testing rim and inflated to the pressure 
corresponding to the maximum load, or maximum dual load where there is 
both a single and dual load marked on the tyre .  If the ty re is tubeless, a tube 
may be inserted to prevent loss of air during the test in the event of puncture.  
 
5.1.2   The tyre shall  be conditioned at room temperature of 21°C for 3 hours before 
the test is conducted.  
 
5.1.3  The tyre pressure shall be readjusted to the value specified in 5.1.1. 
 
5.1.4  The tread shall be cleaned and dried before the test.  
 
5.2 Apparatus  
A plunger with a compressor of a hemispheric steel end, moving vertically at 
a rate of 50 ± 2.5 mm/min., its diameter is chosen according to what is 
specified in Table (1).                 
 
5.2           Test Procedure  
 
5.2.1  Use the cylindrical steel plunger, with a hemispherical end and of specified 
diameter as shown in Table 1(see below).  
 
5.2.2          The plunger  should be forced  perpendicularly into a raised tread element as 
near as possible to the centerline of the tread, at a rate of 50 mm/minute, 
until the tyre breaks or the plunger is stopped by the rim.  
 
5.2.3  Record the force and the distance of penetration just before the  tyre breaks, 
or if it fails to break, just before the plunger is stopped by the rim.  
 
5.2.4 Repeat the plunger application at 72° intervals around the circumference of 
the tyre, until five measurements are made. However, in the case of tyres of 
12 inch rim diameter code or smaller, repeat the plunger application at 120° 
intervals around the circumference of the tyre, until three measurements are 
made . 
 
5.3             Calculations  
 
5.3.1  The breaking energy shall be calculated at each point by means of the   
following formula:  
 
 GSO 646:2017            GSO STANDARD 
 
 
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  deleted paragraphs  5 F x P  
W =    ————————   x  10–3 
  2 
Where:  
W = Energy absorbed at break, N.m  
F = Force just before breaking, N  
P = Penetration just before breaking, mm.  
 
5.3.2 Compute the average breaking energy value for the tyre by calculating the 
average of the values obtaine d in accordance with paragraph 5 .3.1. 
 
5.3.3 The breaking energy of the tyre shall be as the mean value of readings except 
in case the plunger bottoms the rim and the reading is below the minimum 
specified value at any of the measurement points.  
 
5.3.4 If, at all of the measuring points, the plunger bottoms on the rim without 
breaking the tyre, the tyre shall be deemed to have passed the test.  
 
TABLE 1 A 
Strength Test P lunger Diameter  
 
Tyre type and its l oading range*  Plunger diameter (mm)  
Light truck  19.05  
≤12 rim diameter code (except motorcycle)  19.05  
Tubeless:   ≤ 17.5 rim diameter code  19.05  
                   >17.5 rim diameter code, load range  F or less  31.75  
                   > 17.5 rim diameter code, load range over F  38.1 
Tube -type: Load range F or less  31.75  
                    Load range over F  38.1 
 
* TABLE 1B  
Load Range and the Equivalent Rating  
Load range  Ply rating  
A 2 
B 4 
C 6 
D 8 
E 10 
F 12 
G 14 
H 16 
J 18 
L 20 
M 22 
N 24 
 GSO 646:2017            GSO STANDARD 
 
 
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  deleted paragraphs  6 6-  ENDURANCE TEST  
 
6.1 Preparation of T yre 
 
6.1.1 Mount a new tyre on a model rim assembly and inflate it to the inflation 
pressure corresponding to the maximum load rating marked on the tyre. Use 
a single maximum load value when the tyre is marked with both single and 
dual maximum load.   
 
6.1.2 The tyre shall be con ditioned at a temperature of (35 )oC for a period not less 
than 3 hours  before  the test is conducted .  
 
6.1.3  The inflation pressure shall be readjusted to the value at which the tyre has 
been previously adjusted as in 6.1.1 immediately before mounting the tyre rim 
assembly.  
 
6.2 Apparatus  
The apparatus shall consist of the following:  
 
6.2.1 A steel drum (1700 ± 1%)  mm in diameter and of at least the same width as 
the tread of the tyre to be tested.  
 
6.2.2 A spindle on which rim and tyre shall be mounted, provided with a means for 
loading the tyre against the test drum.  
 
6.2.3  A means for rotating the spindle of the  drum within the specified testing 
speeds.  
 
6.2.4 A means for measuring the radial forces at the spindle of the rim and the tyre 
at different speeds during the test.  
 
6.2 Test Procedure  
 
6.2.1 Mount the tyre-rim assembly on the test axle and press it against a flat -faced 
steel test wheel that is 1.7 m ± (1%) in diameter and at least as wide as the 
tread of the tyre.  
 
6.2.2      Apply to the test axle a series of test loads expressed in percent of the load 
indicated, in GSO Regulation No. 645/2017, opposite the load index engraved 
on the sidewall of the tyre, in accordance with the  test programme shown in 
Table 2.   
 
6.2.3 If 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.  
 
  6.2.4  During the test the temperature in the test -room must be maintained between 
(38-44)°C during all phases of testing . 
 GSO 646:2017            GSO STANDARD 
 
 
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  deleted paragraphs  7   6.2.5  The tyre pressure must not be corrected throughout the test and the test load 
must be kept constant throughout each of the three test stages.  
 
  6.2.6  The endurance -test programme shall be carried out without interruption.  
 
  6.2.7 Immediately after running the tyre the required time, measure the tyre 
inflation pressure. Remove the tyre from the model rim assembly, and inspect 
the tyre. 
 
6.2.8      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.  
 
6.2.9  In the case of tyres with a speed category symbol above P, test procedure is 
specified in Appendix A. 
 
 
TABLE 2  
           Loads and Speeds for Endurance Test  
 
Load index  Tyre 
speed  
category  Test-drum speed  Load placed on the wheel as a 
percentage of the load 
corresponding to the load index  
Radial -ply 
km. h-1 Diagonal 
(bias -ply) 
km. h-1 7 h. 16 h.  24 h.  
122 or more  F 
G 
J 
K 
L 
M 32 
40 
48 
56 
64 
72 32 
32 
40 
48 
- 
-  
66 %   
84 %   
101 %  
121 or less  F 
G 
J 
K 32 
40 
48 
56 32 
40 
48 
56 
L 64 56 70 %  88 %  106 %  
   4 h. 6 h. 24 h.  
M 
N 
P 80 
88 
96 64 
- 
- 75 %  
75 %  
75 %  97 %  
97 %  
97 %  114 %  
114 %  
114 %  
Notes:  
(1) "Special -use" tyres (see paragraph 3.6.3 of GSO 645/2017 Regulation) should be tested 
at a speed equal to 85 % of the speed prescribed for equivalent normal tyres.  
 
(2) Tyres with load index 122 or more, speed categories N or P and the  
additional marking "LT", or "C", referred to in 5.12 GSO 645/2017 Regulation, shall be 
tested with the same programme as specified in the above table for tyres with load index 
121 or less.  GSO 646:2017            GSO STANDARD 
 
 
 new paragraphs  
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  deleted paragraphs  8 7-  HIGH SPEED PERFORMANCE TEST  
 
7.1 Preparation of Tyre  
 
7.1.1  Mount a new tyre on a model rim assembly and inflate it to the inflation 
pressure corresponding to the maximum load rating marked on the tyre. Use 
a single maximum load value when the tyre is marked with both single and 
dual maximum load.  
 
7.1.2  The tyre shall be conditioned at a te mperature of (35)oC for a period not less 
than 3 hours before the test is conducted.  
 
7.1.3  The inflation pressure shall be readjusted to the value at which the tyre has 
been previously adjusted as in 7.1.1 immediately before mounting the tyre rim 
assembl y.  
 
7.2 Test Procedure  
 
7.2.1  Mount the tyre -rim assembly on the test axle and press it against a flat -faced 
steel test wheel that is 1.7 m ± (1%) in diameter and at least as wide as the 
tread of the tyre.  
 
7.2.2  Apply a force of 88 % of the maximum load rating marked on the tyre (use 
single maximum load value when the tyre is marked with both single and dual 
maximum loads), and rotate the test wheel at 250 rpm for 2  hours.  
 
7.2.3  Remove the load, allow the tyre to cool to 35 °C, and then adjust the pressure 
to that marked on the tyre for single tyre use. 
 
7.2.4  Reapply the same load, and without interruption or readjustment of inflation 
pressure, rotate the test wheel at 375 rpm for 30 minutes, then at 400 rpm f or 
30 minutes, and then at 425 rpm for 30 minutes.  
 
7.2.5  During the test the temperature in the test -room must be maintained at 35 °C 
during all phases of testing.  
 
7.2.6 Immediately after running the tyre the required time, measure the tyre inflation 
pressure. Remove the tyre from the model rim assembly, and inspect the tyre. 
 
 
  GSO 646:2017            GSO STANDARD 
 
 
 new paragraphs  
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  deleted paragraphs  9 REFERENCES : 
 
1. ECE No. 54 “Uniform provisions concerning the approval of pneumatic tyres for   
             commercial vehicles and their trailers, Revision 3; 26th March 2013 .  
 
2. ECE No. 54 “Uniform provisions concerning the approval of pneumatic tyres for  
commercial vehicles and their trailers, Revision 3/ Amendment 1: 3rd February 
2015 .  
 
3. ECE No. 54 “Uniform provisions concerning the approval of pneumatic tyres for  
commercial v ehicles and their trailers, Revision 3/ Amendment 2; 5th February 
2016 .  
 
4. ECE No. 54 “Uniform provisions concerning the approval of pneumatic tyres for  
commercial vehicles and their trailers, Revision 3/ Amendment 3; 26th March 
2013 . 
  
5. ECE No. 54 “Uniform  provisions concerning the approval of pneumatic tyres for  
commercial vehicles and their trailers, Revision 3/ Corrigendum 1; 18th December 
2014 .  
 
6. ECE No. 54 “Uniform provisions concerning the approval of pneumatic tyres for  
commercial vehicles and their  trailers, Revision 3/ Corrigendum 2; 25th August 
2014 .  
 
7.       FMVSS No. 119 “New pneumatic tires for motor ve hicles with a GVWR of more  
      than 4,536 kilograms (10,000 pounds) and motorcycle”; 2008  
 
8. GS 645 “ Multi -Purpose Vehicles, Trucks, Buses and Trailers Ty res Part 1 ”; 2005 &  
            2009  
 
9. GS 646 “ Multi -Purpose Vehicles, Trucks, Buses and Trailers Ty res Part 2 ”; 1996 &  
            2009  
 
10. GS 647 “ Multi -Purpose Vehicles, Trucks, Buses and Trailers Ty res Part 3 ”; 1996 &  
            2009  
 
 
 
 
 
  GSO 646:2017            GSO STANDARD 
 
 
 new paragraphs  
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  deleted paragraphs  10 APPENDIX A: 
 
1. Load/speed endurance test programme for tyre with speed 
category symbol Q and above  
1.1 This programme applies to:  
1.1.1  All tyres marked with load capacity index in single 121 or less.  
1.1.2 Tyres marked with load capacity index in single 122 and above and 
with the additional marking "C", or "LT", referred to in paragraph 5.12 
GSO 645/2017 Regulation . 
1.2 Load placed on the wheel as a percentage of the load 
corresponding to the load index  Table 3 of GSO 645/12017 
Regulation : 
1.2.1 90% when tested on a test drum 1.70  m ± 1%  in diameter.  
1.2.2 92% when tested on a test drum 2.0  m ± 1%  in diameter.  
1.3 Initial test speed: speed corresponding to the speed category symbol 
less 20  km/h : 
▪ Time to reach  the initial test speed 10 min.  
▪ Duration of the first step = 10 min.  
1.4 Second test speed: speed corresponding to the speed category 
symbol less 10 km/h : 
▪ Duration of the second step = 10 min.  
1.5 Final test speed: speed corresponding to the speed category  symbol:  
▪ Duration of the final step = 30 min.  
1.6. Total test duration: 1 h.  
2. Equivalent test methods  
If a method other than that described in paragraph 5 above is used, 
its equivalence must be demonstrated.