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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 17394-1998 Laboratory Test Methods for Passenger Car Tyres Capabilities. The following main technical changes have been made with respect to GB/T 4502-2009:
——The definitions of test drum speed and test speed are modified and increased (see 3.1 and 3.2, and 3.1 of 2009 edition);
——The accuracy requirement of filling pressure gauge is modified into “±5 kPa” (see 4.4, and 4.4 of 2009 edition);
——The setting requirements on the horizontal distance P value of bead unseating pressing block are modified, P value shall be determined according to the requirements of Table 2 (see Table 2, and Table 2 of 2009 edition);
——Relevant contents about Type C bead unseating pressing blocks can be used for other tubeless tyre for passenger cars with nominal rim diameter of 10~19 and height-width ratio less than or equal to 30 are modified and added (see 5.1.1.6, and 5.1.1.6 of 2009 edition);
——"Apply acting force increasingly on the external surface tyre side at the speed of 50 mm/min±2.5 mm/min until the tyre is separated from the rim or the minimum bead unseating resistance value specified in Table 7 is reached." is changed to “Bead unseating pressing blocks shall increasingly apply force gradually to the external surface on tyre side at the moving speed of 50 mm/min±2.5 mm/min, until reaching the minimum bead unseating resistance specified in Table 8, the force may be applied to the final test point until bead unseating or contacting the rim. Correct the pressure before moving to the next point for test” (see 5.1.2.4, and 5.1.2.4 of 2009 edition).
——The requirement that "It shall be noted if pressing block slips or press the rim." (see 5.1.2.5);
——As for high speed test, the test conditions and test procedure for passenger car tyres with speed larger than 300 km/h are added (see 5.3.1.7, 5.3.1.8, 5.3.2.4 and Table 6);
——Special requirement that the test speed for endurance test and low pressure performance test of snow tyres are added (see 5.4.1.6 and 5.5.1.3);
——The inspection requirements after completion of endurance test are modified, i.e. "dismantle after complete cooling and inspect tyre appearance" is changed into "inspect tyre appearance after complete cooling without dismantling" (see 5.4.2.4, and 5.4.2.4 of 2009 edition);
——The judgment criteria that "it is deemed to have passed the test if it is free from bead unseating but reaches the rim" is added (see 6.2);
——The high-speed performance judgment criteria description is modified, " no visual evidence of tread, sidewall, ply, belt, breaker, bead, inner liner separation, chunking, open splices, cracking or ply cracking, cords separation, cords break, etc." is changed into "no visual evidence of tread, sidewall, ply, inner liner, belt or breaker, bead separation, ply cracking, cords separation, cords break, chunking, open splice, cracking and body shape distortion, etc." (see 6.4, and 6.4 of 2009 edition);
——The endurance performance judgment criteria description is modified, "no visual evidence of tread, sidewall, ply, belt, breaker, bead, inner liner separation, chunking, open splices, cracking or ply cracking, cords separation, cords break, etc." is changed into "there shall be no tread, sidewall, ply, belt or breaker, bead separation, ply cracking, cords separation, cords break, chunking, open splice, cracking and body shape distortion, etc." (see 6.5, and 6.5 of 2009 edition);
——The low pressure performance judgment criteria description is modified, "no visual evidence of tread, sidewall, ply, belt, breaker, bead, inner liner separation, chunking, open splices, cracking or ply cracking, cords separation, cords break, etc." is changed into "there shall be no tread, sidewall, ply, inner liner, belt or breaker, bead separation, ply cracking, cords separation, cords break, chunking, open splice, cracking and body shape distortion, etc." (see 6.6, and 6.6 of 2009 edition);
This standard has been redrafted and modified in relation to ISO 10191: 2010 Passenger Car Tyres - Verifying Tyre Capabilities - Laboratory Test Methods.
There are many structural changes in this standard compared with compared with ISO 10191:2010; see Annex A for the comparison between clause numbers of this standard and those of ISO 10191: 2010.
There are some technical differences between this standard and ISO 10191:2010, and these differences are marked with perpendicular single line (｜) on the margin of relevant clauses. The technical differences, together with their justifications, are given below:
For the convenience of application, the following editorial changes are also made in this standard:
——Bibliography of the international standard is deleted.
This standard was proposed by China Petroleum and Chemical Industry Federation.
This standard is under the jurisdiction of SAC/TC 19 National Technical Committee 19 on Tyres and Rims of Standardization Administration of China.
The previous editions of the standards superseded by this standard are as follows:
——GB/T 4502-1984, GB/T 4502-1998, GB/T 4502-2009;
——GB/T 4503-1984, GB/T 4503-1996, GB/T 4503-2006;
——GB/T 4504-1984, GB/T 4504-1998;
——GB/T 7034-1986, GB/T 7034-1998.
Laboratory Test Methods for Passenger Car Tyres Capabilities
1 Scope
This standard specifies test methods for verifying the capabilities of tyres for passenger cars, including terms and definitions for test, test equipment and accuracy, test conditions, test procedure, judgment criterion and test report, etc. Of the test methods presented, only some may be required depending on the type of tyre to be tested (with inner tube or tubeless, diagonal tyre or radial tyre, etc.).
This standard includes:
(1) The bead unseating test, assesses the resistance of the tyre to bead unseating. It applies to tubeless tyres only.
(2) The strength test - test the capability of the tyre structure with respect to braking energy of tread cap.
(3) The high speed test, assesses the capability of the tyre according to its speed symbol.
(4) The endurance test, assesses the resistance of the tyre with respect to service at specified load and speed.
(5) The low pressure test, assesses the reliability of radial tyre at low voltage state with respect to service at specified load, speed and low pressure.
The test methods presented in this standard are not intended for gradation of tyre performance or quality levels.
This standard applies to all passenger car tyres.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2978 Size Designation, Dimensions, Inflation Pressure and Load Capacity for Passenger Car Tyres
GB/T 6326 Tyre Terms and Definitions (GB/T 6326-2014, ISO 4223-1:2002, NEQ)
GB 9743 Passenger Car Tyres
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 6326 and the following apply.
3.1
test drum speed
test speed
peripheral speed of the steel test drum
4 Test Equipment and its Accuracy
4.1 Bead unseating resistance tester
4.1.1 Basic structure and main location dimension of the tester are shown in Figure 1.
4.1.2 The tester shall be equipped with standard bead unseating block (Type A, Type B and Type C) and the dimension, shape and manufacturing material are shown in Figure 2.
4.1.3 The bead unseating block loading device shall permit progressive application of the force. Indicators of displacement and force provided shall be accurate to within ± 1 % of full scale.
4.1.4 For the bead unseating block, the displacement speed accuracy shall be controlled within ±3% of the full scale.
4.2 Strength tester
4.2.1 The tester shall be equipped with a long cylindrical metal pressure head with its end shaped like a hemisphere of 19 mm±0.5 mm diameter.
4.2.2 The pressure head equipment shall be able to gradually apply force. Force and displacement indicator shall have an accuracy within ±1% of full scale.
4.2.3 The displacement speed accuracy of pressure head shall be within ±3% of the full scale.
4.3 High-speed endurance tester
4.3.1 The diameter of test drum is 1700mm ± 17mm.
4.3.2 Test drumhead of the tester drum shall be smooth steel surface whose width shall be greater than or equal to overall section width of the test tyre.
4.3.3 The loading capacity of the test loading device shall be able to meet the requirements of test methods, with accuracy of ±1% of the full scale.
4.3.4 The speed capability of the equipment shall be adequate for the requirements of the test methods. The accuracy of the test drum speed shall be within km/h.
4.3.5 Radial runout of tester drum shall be less than or equal to 0.25mm.
4.3.6 Ambient temperature measurement unite shall be arranged within 150mm~1m from the test tyre.
4.4 Inflation pressure gauges
With a maximum scale value of at least 500 kPa and an accuracy within ±5 kPa.
Dimensions in millimetres
Figure 1 Bead Unseating Resistance of Tyre
Dimensions in millimetres
Type A
Type B
Type C
Key:
Material: AL-Si2 Mg Ti or AL-Si7Mg0.3 (see ISO 2107);
Condition: TF (see ISO 3522);
Surface roughness: Ra 1.25 μm.
Figure 2 Shape and Dimension of Bead Unseating Pressing Block
5 Test Method
5.1 Bead unseating resistance test
5.1.1 Test conditions and test preparation
5.1.1.1 Test tyre shall be tubeless tyre for passenger cars, and appearance quality shall meet the requirements of GB 9743. Bead shall be clean and dry before installation.
5.1.1.2 Test rim should meet the requirements of GB/T 2978 about measuring rim. Before installation, fitting surface between bead seat and tyre shall be guaranteed clean and dry.
5.1.1.3 Test tyre shall be installed on the test rim without any auxiliary materials for lubrication or adhesion, and then filled into pressure specified in Table 1.
Table 1 Inflation Pressure for Test of Bead Unseating Resistance/Strength/Endurance Test of Tubeless Tyre for Passenger Cars
T type temporary use spare tyre Other radial tyres Other diagonal tyres
Standard Reinforced 4PR, 6PR 8PR
360 180 220 180 220
5.1.1.4 At least 4 test points distributed with equal interval along circumferential direction are determined on the side of tyres, marked and numbered one by one.
5.1.1.5 Assembly of test tyre and rim after inflation shall be placed at the ambient temperature of 18℃~36℃ for 3h.
5.1.1.6 P values of horizontal distance of bead unseating pressing block are shown in Table 2; for T type temporary use spare tyre, Type A bead unseating pressing block shown in Figure 2 shall be adopted; for other tubeless passenger car tyres with nominal rim diameter of 10~19 and nominal height-width ratio larger than or equal to 35, Type A or Type B bead unseating pressing blocks shown in Figure 2 shall be adopted; for other tubeless passenger car tyres with nominal rim diameter of 10~19 and nominal height-width ratio less than or equal to 30, Type A, Type B or Type C pressing block shown in Figure 2 shall be adopted; for other tubeless passenger car tyres with nominal rim diameter of 20~28, Type C shown in Figure 2 shall be adopted.
