GB/T 4502-2023Laboratory test methods for passenger car tyres capabilities (English PDF)

Foreword

This document was issued on 23 May 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 December 2023.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

This document was drafted in accordance with the provisions of GB/T 1.1-2020

Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents.

This document replaces GB/T 4502-2016 Laboratory test methods for passenger car

tyres capabilities. Compared with GB/T 4502-2016, except for the structural

adjustment and editorial revisions, the main technical changes are as follows.

-- The scope of application is changed (see Chapter 1; see Chapter 1 of the 2016

edition);

-- The term and definition of "test drum speed" is deleted (see 3.1 of the 2016

edition);

-- The term and definition of "parasitic tread block chunking" is added (see 3.1);

-- The type of standard pressing block for bead unseating that the testing machine

shall be equipped with is changed (see 4.1.2; see 4.1.2 of the 2016 edition);

-- The requirement that the accuracy of the P value indicator is +/-1 mm is added

(see 4.1.5);

-- The regulation that the maximum range of the inflation pressure gauge shall be

at least 500 kPa is deleted (see 4.4 of the 2016 edition);

-- The instructions and requirements for the test samples are changed, and they

constitute a separate chapter (see Chapter 5; see 6.1 of the 2016 edition);

-- The content that appearance quality shall comply with the provisions of GB 9743

is deleted (see 5.1.1.1, 5.2.1.1, 5.3.1.1, and 5.4.1.1 of the 2016 edition);

-- The regulations on test rims are changed (see 6.1.1.2, 6.2.1.1, 6.3.1.1, and 6.4.1.1;

see 5.1.1.2, 5.2.1.2, 5.3.1.2, and 5.4.1.2 of the 2016 edition);

-- The scope of use of different types of pressing blocks for bead unseating is

changed (see 6.1.1.6; see 5.1.1.6 of the 2016 edition);

-- The rounding rule of the H value related to the calculation of P value is changed

(see Table 2; see Table 2 of the 2016 edition);

-- The description of "If the same set of tyre and rim assembly used for the bead

unseating resistance test is used, the test can be continued." is added (see 6.2.1.3);

-- The provision of "If the device for automatically calculating the breaking energy

is used, when the specified minimum breaking energy is reached, the indenter

shall be immediately stopped pressing into the tyre." is added (see 6.2.2.8);

-- The requirement that necessary means used to maintain the specified test

pressure during the test shall be noted in the test report is added (see 6.2.2.9);

-- The regulation that when the same sample is used for the second test of the

passenger car tyre with a speed exceeding 300 km/h, it needs to be stood and

the tyre pressure shall be readjusted is added (see 6.3.1.7);

-- The requirement that "no bead unseating but slippage" is considered to pass the

test is added to the judgment rule of the bead unseating resistance test (see 7.1);

-- The provision of "If the rim is touched and the tyre isn't punctured, the tyre is

judged to pass the test." is added to the judgment rule of the strength

performance (see 7.2);

-- The description of "Tyres with a maximum speed of 300 km/h and above may

have bulges on the tread surface or chunking caused by bulging." is added to the

judgment rule of the high-speed performance (see 7.3);

-- The provision of "chunking (except PTBC of snow tyres)" is added to the

judgment rules of the endurance test and low-pressure performance (see 7.4,

7.5);

-- The provision of "slippage or the rim is touched" is added to the condition of

each test point of the tyre in the test report of bead unseating resistance [see j)

in Chapter 8].

This document is modified in relation to ISO 10191.2021 Passenger car tyres -

Verifying tyre capabilities - Laboratory test methods.

Compared with ISO 10191.2021, this document has more structural adjustments; the

comparison list of structure numbers between the two documents is shown in Appendix

A.

Compared with ISO 10191.2021, this document has many technical differences, and

the outer margin of the terms involved is marked with a vertical single line (|). See

1 Scope

GB/T 4502-2023 covers the bench tests that decide whether a passenger car tyre is fit to sell - the test equipment and the precision it has to hold, the samples drawn for each test, the test methods themselves, the judgment rules, and the report. The methods run through bead unseating resistance, tyre strength, high speed, endurance and low-pressure behaviour, which between them stand in for the ways a tyre fails on the road: a bead that walks off the rim under a hard cornering load, a casing that gives way against a kerb or a pothole, a carcass that overheats at sustained speed, and a tyre run soft that destroys itself from the inside. Because the verdict is a plain pass or fail against tabulated limits, the standard has to fix everything that would otherwise let two laboratories disagree - the shape, dimensions and material of the pressing blocks used to unseat the bead, the test rim, the condition and preparation of the sample tyres, and what the report must carry so a result can be traced back to a particular production run. The terms clause names defect modes such as parasitic tread block chunking. Written for tyre manufacturers, vehicle makers and testing laboratories; an informative annex maps the clause numbering onto ISO 10191:2021.

This document describes the laboratory test methods for performance testing of

passenger car tyres, including test equipment and its precision, test conditions, test

procedures, judgment rules and test reports.

2 Normative references

The following documents contain the provisions which, through normative reference in

this document, constitute the essential provisions of this document. For the dated

referenced documents, only the versions with the indicated dates are applicable to this

document; for the undated referenced documents, only the latest version (including all

the amendments) is applicable to this document.

GB/T6326 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 judgment of limiting values

3 Terms and definitions

Terms and definitions defined in GB/T 6326 and the following apply to this document.

3.1 parasitic tread block chunking; PTBC

A defect characterized by rubber pieces separated from the tyre tread or tearing without

exposing the tyre reinforcing material (such as carcass ply, belt, etc.).

4 Test equipment and its precision

The testing machine shall be equipped with standard pressing blocks for bead

unseating (A-type and C-type), and the size, shape and manufacturing materials shall

comply with the provisions of Appendix C.

The testing machine shall be equipped with a sufficiently long cylindrical metal

indenter, and the end of the indenter is hemispherical with a diameter of 19 mm+/-0.5 mm.

5 Test samples

According to the needs of the test, the test samples are 3 to 5 identical tyres, which are

used for bead unseating resistance test and strength test, high-speed test, endurance test

and low-pressure performance test respectively.

6 Test methods

The test tyres shall be tubeless passenger car tyres, and the bead parts shall be

clean and dry before installation.

The test rim should comply with the provisions of GB/T 2978 or relevant

industry technical documents on measuring rims.

7 Judgment rules

After the test is completed according to the requirements of 6.1, if the bead unseating

resistance of each test point is not less than the specified value in Table 8, the sample is

judged as "pass the test"; otherwise, it is judged as "fail the test"; the situation that the

bead has not been unseated but the pressing block slips or touches the rim is deemed as "pass the test".

8 Test report

The test report shall include the following content.

a) the manufacturer name, trademark, specification, and production number of

the test tyre;

b) the load index or ply rating, maximum load capacity, speed symbol, material,

and structure of the test tyre, etc.;

c) test rim specifications.

......

Appendix B for a list of these technical differences and their reasons.

The following editorial changes have been made to this document.

-- In order to coordinate with the existing standard, the name of the standard is

changed to "Laboratory test methods for passenger car tyres capabilities";

-- The informative reference GB/T 2978 is added;

-- Appendix A (informative) the comparison list of structure numbers between this

document and ISO 10191.2021 is added;

-- Appendix B (informative) the list of technical differences between this document

and ISO 10191.2021 and their reasons is added;

-- Appendix A (informative) of ISO 10191.2021 High-speed test - Test conditions

for tyres without service description marking is deleted.

Please note that some of the content of this document may involve patents. The issuing

agency of this document is not responsible for identifying patents.

This document was proposed by China Petroleum and Chemical Industry Federation.

This document shall be under the jurisdiction of the National Technical Committee on

Tyres and Rims of Standardization Administration of China (SAC/TC19).

The previous versions of the documents replaced by this document are as follows.

-- GB/T 4502 was first published in 1984 and first revised in 1998;

-- When it was revised for the second time in 2009, GB/T 4503-2006 Test method

of strength for passenger car tyres (the previous versions of GB/T 4503-2006

are as follows. it was first published in 1984, first revised in 1996 and secondly

revised in 2006), GB/T 4504-1998 Bead unseating resistance test for tubeless

passenger car tyres (the previous versions of GB/T 4504-1998 are as follows. it

was first published in 1984 and first revised in 1998), and GB/T 7034-1998 High

speed test for passenger car tyres - Drum method (the previous versions of

GB/T7034-1998 are as follows. it was first published in 1986 and first revised

in 1998) were incorporated;

-- The third revision was in 2016;

-- This is the fourth revision.

Laboratory test methods for passenger car tyres capabilities