GB/T 4502-2023 in English

《GB/T 4502-2023轿车轮胎性能室内试验方法》由TC19（全国轮胎轮辋标准化技术委员会）归口，TC19SC1（全国轮胎轮辋标准化技术委员会汽车工农业机械轮胎轮辋分会）执行，主管部门为中国石油和化学工业联合会。

Laboratory test methods for passenger car tyres capabilities

1 Scope

This document specifies laboratory test methods for passenger car tyres capabilities, including test equipment and precision, test conditions, test procedures, judgment rules and test report.

This document includes bead unseating resistance test, strength test, high-speed test, endurance test and low-pressure test of tyres. 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.).

The test methods presented in this document are not intended for gradation of tyre performance or quality levels.

This document is applicable to new passenger car pneumatic tyres and refurbished passenger car pneumatic tyres, and other tyres may be tested by reference to this document upon agreement of the relevant parties.

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 6326 Tyre terms and definitions (GB/T 6326-2014, ISO 4223-1:2002, NEQ)
GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values

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
parasitic tread block chunking (PTBC)
breaking away of pieces, or tearing, of rubber within a tread block without exposing reinforcing material (e.g., polyamide overlay or steel belts)
Note: PTBC is an artefact of testing a loaded tire on a roadwheel; it is not indicative of a tire structural problem and does not occur in real-world operation. It generally occurs in the endurance test of tyres with soft tread compounds and/or complex tread geometry, e.g. including many sipes.

4 Test equipment and precision

4.1 Bead unseating resistance tester

4.1.1 Basic structure and main location dimension of the tester are shown in Figure 1.

Dimensions in millimeters

Key:
P — Horizontal distance of bead unseating pressing block

Figure 1 Bead unseating resistance tester of tyres

4.1.2 The tester shall be equipped with standard bead unseating pressing block (Type A and Type C) and the dimension, shape and manufacturing material are shown in Annex C.

4.1.3 For the bead unseating block, the loading device shall permit gradual application of the force. Indicators of displacement and force provided shall have a precision within ±1% of full scale.

4.1.4 For the bead unseating block, the displacement speed shall be controlled with a precision within ±3% of the full scale.

4.1.5 The precision of P-value indicator is ±1 mm.

Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 Test equipment and precision
5 Test sample
6 Test methods
7 Judgment rules
8 Test report
Annex A (Informative) Comparison of structure changes between this document and ISO 10191:2021
Annex B (Informative) Technical deviations between this document and ISO 10191:2021 and their justifications
Annex C (Nominative) Shape and dimensions of bead unseating pressing block
Bibliography