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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 1702-2008 Cycle tyres, and the following main technical changes have been made with respect to GB/T 1702-2008:
——Diagrams of different tyre types are modified to show more detailed sections of tyre components (see Clause 4 of this standard and Clause 4 of Edition 2008);
——Item 3 in "Table 1 Tyre performance" is modified: "ozone aging resistance of sidewall rubber of non-black tyres" is modified into "ozone aging resistance of sidewall rubber"; and the performance indicator "within chap C-2 specified in Annex D" is modified to "the chap degree shall not exceed C-2 specified in Annex B" (see 5.3 of this standard and 5.3 of Edition 2008);
——Item 5 in "Table 1 Tyre performance" is modified: the "Tensile strength of bead ring/KN" is modified into "Tensile strength of bead/KN"; and the performance indicator "straight side, hooked bead, and crotchet type tyres" is modified into "tyres with steel wire or fiber material as bead” (see 5.3 of this standard and 5.3 of Edition 2008);
——Items 6 and 7 in "Table 1 Tyre performance" are modified, and the test result unit of cord fabric’s tensile strength and adhesion strength is changed from kN/m to N/mm (see 5.3 of this standard and 5.3 of Edition 2008);
——Footnote "a" in Table 1 is modified: the mileage of tread rubber wear test is changed from 1.6 km to 1.61 km (see 5.3 of this standard and 5.3 of Edition 2008);
——In the preparation of specimens for the tread rubber wear test, "polish the specimens cut on the grinding wheel to a thickness of 2.0 mm ± 0.2 mm" is modified into "the specimens cut shall have a thickness of 2.0 mm ± 0.2 mm" [see 6.3.2b) of this standard and 6.3.2.2 of Edition 2008];
——In the cord tensile strength test, "use a cord tensile tester, canvas tensile tester or rubber tensile tester" is modified into "use a tensile tester" (see 6.7 of this standard and 6.7 of Edition 2008);
——In the test of adhesion strength between tread rubber and ply, "clamp the specimen with a fixture of the rubber tensile tester" is modified into "clamp the specimen with a fixture of the tensile tester" (see 6.8.1 of this standard and 6.8.1 of Edition 2008);
——Two marks, namely, tubeless tyre and tyre driving direction, are added (see 7.1 of this standard and 7.1 of Edition 2008);
——In “Table A.1 Tyre appearance quality”, appearance defects related to unclear tyre marks and their permissible ranges are added and footnote "b" of "Nonconformity category" is added (see Annex A of this standard and Annex C of Edition 2008);
——The requirement that "The storage period shall not exceed 1 year from the date of manufacture under this storage conditions" is deleted (see E.2.5 of Edition 2008).
This standard was proposed by China Petroleum and Chemical Industry Federation.
This standard is under the jurisdiction of the National Technical Committee 19 on Tyres and Rims of Standardization Administration of China (SAC/TC19).
The previous editions of the standard replaced by this standard are as follows:
——GB 1702-1979, GB 1702-1986, GB/T 1702-1992, GB/T 1702-1997 and GB/T 1702-2008.
Cycle tyres
1 Scope
This standard specifies the terms and definitions, types, requirements, test methods, and marking, packaging, transportation and storage of cycle tyres.
This standard is applicable to pneumatic tyres specified in GB/T 7377.
This standard is not applicable to tubular tyres for racing cycle and non-pneumatic 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 528 Rubber, vulcanized or thermoplastic - Determination of tensile stress-strain properties
GB/T 1689 Rubber vulcanized - Determination of abrasion resistance (Akron machine)
GB/T 2941 Rubber - General procedures for preparing and conditioning test pieces for physical test methods
GB/T 6326 Tyre terms and definitions
GB/T 7377 Series of cycle tyres
GB/T 9749 Performance testing method for cycle tyres
HG/T 2906 Static loaded performance testing method for cycle 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
non-weighted type
tyres with a load < 120 kg
3.2
weighted type
tyres with a load ≥ 120 kg
4 Diagrams of different tyre types
4.1 Straight side (SS) tyre is shown in Figure 1a).
4.2 Hook bead (HB) tyreis shown in Figure 1b).
4.3 Beaded edge (BE) tyreis shown in Figure 1c).
4.4 Croctchet type (CT) tyre is shown in Figure 1d).
a) Section of straight side tyre b) Section of hook bead tyre
c) Section of beaded edge tyre d) Section of croctchet type tyre
Key:
1——tread; 8——specified rim diameter (D);
2——section width (S); 9——bead seat;
3——maximum overall width (W); 10——rim;
4——crown thickness; 11——measuring rim width (Rm);
5——section height (H); 12——bead;
6——sidewall; 13——sidewall inscription or decorative pattern;
7——maximum overall diameter (D0); 14——beaded edge bead rubber.
Figure 1 Diagrams of tyre types
5 Requirements
5.1 Sizes, basic parameters and main dimensions of tyres
The sizes, basic parameters and main dimensions of tyres shall meet the requirements of GB/T 7377.
5.2 Appearance
Tyres shall be mounted on rims manufactured in accordance with GB/T 7377 or agreed upon by the supplier and the purchaser, and shall be free from obvious swing upon visual inspection. See Annex A for appearance quality requirements of tyres.
5.3 Performance
Tyre performance shall meet those specified in Table 1.
Table 1 Tyre performance
S.N. Item Test Performance indicator Test clause
1 Tensile strength/MPa Tread rubber tensile test Non-weighted type >8.0 6.2
Weighted type >11.7
Elongation at break/% Non-weighted type >350
Weighted type >400
2 Wear loss of black tyre/cm3 Tread rubber wear test a ≤1.2 6.3
3 Ozone aging resistance of sidewall rubber Ozone aging test of sidewall rubber The chap degree shall not exceed C-2 specified in Annex B 6.4
4 Bending resistance of beaded edge bead rubber Bending resistance test of beaded edge bead rubber Beaded edge tyre No fracture 6.5
5 Tensile strength of bead/kN Bead tensile strength test Tyres with steel wire or fiber material as bead >3.2 6.6
6 Cord fabric tensile strength/(N/mm) Cord tensile strength test Non-weighted type >40 6.7
Code of nominal section width of weighted tyres <2½ (or 67) 2PR >50
4PR >32
≥2½ (or 67) 2PR >50
4PR >40
6PR >32
7 Adhesion strength/(N/mm) Adhesion strength test Between tread rubber and ply >2.5 6.8
Between plies >3.0
8 Breaking energy/J Strength test Non-weighted type >7.0 6.9
Code of nominal section width of weighted tyres <2½ (or 67) 2PR >10.0
4PR >12.0
≥2½ (or 67) 2PR >10.0
4PR >16.0
6PR >20.0
9 Bead unseating resistance of tyre/kPa Bead unseating hydrostatic test Code of nominal section width of non-weighted tyres <37 (or 1.375) >800 6.10
≥37 (or 1.375)
<47 (or 1.75) >600
≥47 (or 1.75) >500
10 Machine test mileage/km Endurance test Nominal overall diameter (or nominal rim diameter) of non-weighted tyres Nominal overall diameter ≤ 18 (or nominal rim diameter ≤ 355) 2,000 6.11
Nominal overall diameter between 20 and 25 (or nominal rim diameter between 406 and 547) 3,000
Nominal overall diameter ≥ 26 (or nominal rim diameter ≥ 559), suitable for nominal section width code < 37 (or 1.375)
Nominal overall diameter ≥ 26 (or nominal rim diameter ≥ 559), suitable for nominal section width code ≥ 37 (or 1.375) 5,000
a Tread wear test mileage is 1.61 km.
6 Test methods
6.1 Determination of tyres' basic parameters and main dimensions
The tests for determining basic parameters and main dimensions of tyres shall be carried out in accordance with HG/T 2906.
6.2 Tread rubber tensile test
6.2.1 The test shall be carried out in accordance with those specified in GB/T 528 and Type 2 cutter shall be used.
6.2.2 Specimen preparation steps:
a) Cut not less than 5 specimens from the middle of the crown or sidewall along the longitudinal direction;
b) If it is impossible to take standard specimens in special circumstances, the part of the specimen to be clamped may be determined based on the actual situation.
6.2.3 If it is difficult to take specimens, the test may be carried out using standard specimens made of tread rubber in accordance with GB/T 2941.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Diagrams of different tyre types
5 Requirements
6 Test methods
7 Marking, packaging, transportation and storage
8 Miscellaneous
Annex A (Normative) Appearance quality requirements
Annex B (Normative) Chap evaluation method
Annex C (Normative) Transportation and storage
