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This standard is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization –– Part 1: Rules for the structure and drafting of standardizing documents.
This standard replaces GB/T 518-2007 motorcycle tyres. The following main technical changes have been made with respect to GB/T 518-2007:
——The terms and definitions of motorcycle radial tyre are added (see Clause 3);
——”Load index (the corresponding ply ratings or their indications are added for the code-designated series)” is added (see 4.1);
——”The minimum breaking energy of tyres shall not be lower than that specified in Table 1” in the strength performance requirements is revised to “The breaking energy of strength test at each test point shall not be lower than that specified in Table 1” (see 4.5.1 herein and 4.2.1 of 2007 edition);
——The application of maximum travel speeds is revised to speed symbol J and above for tyres subjected to high-speed performance test (see 4.5.3 herein and 4.2.3 of 2007 edition);
——The requirement “the tread abrasion mark shall be provided in the groove within 1/2 tread width from the center of the crown” is added (see 4.6.1);
——The “Place name” in the marking is revised to “Place of origin” [see 6.1b) herein and 6.1b) of 2007 edition];
——The “ply rating or load index” in the marking is revised to “load index (the corresponding ply ratings or their indications are added for the code-designated series)” [see 6.1c) herein and 6.1c) of 2007 edition];
——The marking requirement of “Tyres of metric series and code indicating series shall be marked with speed symbols” is deleted (see 6.2 of 2007 edition); It is modified to the requirement that all motorcycle tyres shall have speed symbols [see 6.1d)];
——The “Framework material” in the marking is revised to “Name of framework material for crown and sidewall of radial tyre and its layer number, name of framework material for bias-ply tyre” [see 6.1e) herein and 6.1d) of 2007 edition];
——The marking requirements for the position marking of tread abrasion marks are added [see 6.1f)];
——Some distinctive marks for tread types C and D are added (see 6.7, 6.8 and 6.9);
——The marks of moped motorcycle tyres are added (see 6.10);
——The overall dimension requirements of new tyre are added (see Annex A);
——The correlation table between tyre speed symbol and maximum travel speed is added in Annex B.
——The correlation table between tyre load index and tyre load capability is added in Annex C.
This standard was proposed by and is under the jurisdiction of the Ministry of Industry and Information Technology of the People's Republic of China.
The previous editions of this standard are as follows:
——GB 518-1965, GB 518-1974, GB 518-1991, GB 518-1997, GB 518-2007.
Motorcycle tyres
1 Scope
This standard specifies requirements, test methods and markings of the motorcycle tyres.
This standard is applicable to new pneumatic motorcycle tyres.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 521 Test method of measuring peripheral dimensions for tyres
GB/T 2983 Series of motorcycle tyres
GB/T 6326 Tyre terms and definitions
GB/T 7036.2 Inner tube of pneumatic tyres — Part 2: Inner tube of motorcycle tyres
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 13203 Test methods for verifying capabilities of motorcycle tyres
HG/T 2177 Appearance quality of 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
motorcycle radial tyre
pneumatic motorcycle tyres in which the cords of carcass ply are arranged at 65°~90°to the centerline of the tread and the carcass is banded by a belt
4 Requirements
4.1 Specification of tyres, load index (the corresponding ply ratings or their indications are added for the code-designated series), load capacity, measuring rim, permitted rim and inflation pressure
They shall be in accordance with those specified in GB/T 2983 or in the related technical documents of the industry.
Note: Related technical documents of the industry are only applicable to motorcycle tyres that are beyond the scope of GB/T 2983.
4.2 Overall dimension of new tyres
They shall be in accordance with those specified in Annex A.
4.3 Correlation between tyre speed symbol and maximum travel speed
It shall be in accordance with those specified in Annex B.
4.4 Correlation between tyre load index and tyre load capability
It shall be in accordance with those specified in Annex C.
4.5 Safety performance
4.5.1 Strength performance
Tyres shall be subjected to strength performance test, and the breaking energy of the test at each test point shall not be lower than that specified in Table 1.
Table 1 Minimum breaking energy of various types of tyres
Tyre load type Corresponding ply rating Design section width
≤62 mm >62 mm
Light-load 2PR 15 J 17 J
Standard 4PR 29 J 34 J
Reinforced 6PR 39 J 45 J
Heavy-load 8PR 48 J 56 J
Note 1: The breaking energy of moped motorcycle tyres is assessed according to the light-load type.
Note 2: The load index specified in GB/T 2983 or related technical documents may be consulted for the corresponding tyre load type.
4.5.2 Durability
Tyres shall be subjected to durability test. After the durability test, the tyre shall not have defects such as separation, chunking, cracking, joint crack, cord crack or fracture. The test tyre pressure shall not be lower than the initial pressure.
4.5 High-speed performance
Tyres with speed symbol J or above shall be subjected to high-speed performance test. After high-speed performance test, the tyre shall not have defects such as separation, chunking, cracking, joint crack, cord crack or fracture. Test tyre pressure shall not be lower than the initial pressure.
4.6 Tread abrasion mark
4.6.1 Each tyre shall be provided with at least three clearly observed tread abrasion indicators equidistantly along the circumferential direction, and the tread abrasion mark shall be provided in the groove within 1/2 tread width from the center of the crown, with a height not be less than 0.8 mm.
4.6.2 The shoulders on both sides of the tyre shall be engraved to indicating the position of tread abrasion marks.
4.7 Appearance quality
4.7.1 The tyre shall be free from appearance defects that seriously affect its service life, such as separation between various parts, sponginess, drawing up and fracture of the bead ring, breaking of multiple cords, wrinkled cords in tyre cavity and crown cord flashing, etc. The shape of the cushion belt shall be complete and the belt body shall not be cracked.
4.7.2 Other appearance quality of tyre and cushion belt shall comply with the provisions of HG/T 2177.
4.8 Inner tube
The inner tube, if any, shall be in accordance with those specified in GB 7036.2.
5 Test methods
5.1 See GB/T 2983 or related technical documents of the industry for the test parameters involved in the test method, such as tyre specification, load index, load capacity, measuring rim, permitted rim and inflation pressure. See Annex B for the correlation between speed symbol and maximum speed. See Annex C for correlation between load index and tyre load capability.
5.2 The outer diameter, section width and tread abrasion mark height of the new tyre after inflation shall be measured in accordance with GB/T 521.
5.3 The strength, durability and high-speed performance of tyre shall be tested in accordance with GB/T 13203.
5.4 The tyre appearance quality shall be inspected in accordance with HG/T 2177.
5.5 The inner tube may be inspected in accordance with GB/T 7036.2 if necessary.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
5 Test methods
6 Markings
Annex A (Nominative) Overall dimension requirements of new tyres
Annex B (Nominative) Correlation between speed symbol and maximum travel speed of tyre
Annex C (Nominative) Correlation between load index and tyre load capability