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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces HG/T 2906-2009 Static loaded performance testing method for cycle tyres. In addition to editorial changes, the following main technical changes have been made with respect to HG/T 2906-2009:
——normative reference GB/T 8170 is added (see Clause 2);
——the requirement for the maximum measuring range of the pressure gauge is deleted, and the precision tolerance of the pressure gauge is modified and unified to ±10kPa (see 4.2; 4.2 of Edition 2009);
——the value of π in the calculation equation of outer diameter is modified to two decimal places (see 5.2.2; 5.2.2 of Edition 2009);
——the description that "or other equivalent modes” may be used to obtain pattern prints (see 5.2.6);
——the requirements of "the calculation results of A.2 and A.4 are accurate to one decimal place, the calculation results of A.3 and A.5 are accurate to two decimal places, and the measurement and calculation results are rounded off according to the requirements of GB/T 8170" are added (see 5.2.12);
——the error in the calculation equation of hardness coefficient is corrected (see A.3; A.3 of Edition 2009);
——the "average pressure of print area" is modified to "average grounding pressure" and the unit conversion coefficient 103 of the calculation equation is added (see A.4; A.4 of Edition 2009).
This standard was proposed by China Petroleum and Chemical Industry Association.
This standard is under the jurisdiction of the National Technical Committee on Tyres and Rims of Standardization Administration of China (SAC/TC19).
The previous editions of this standard are as follows:
——GB/T 9748-1988; HG/T 2906-2009.
Static loaded performance testing method for cycle tyres
1 Scope
This standard specifies the terms and definitions, test equipment and precision, test methods and test report for performance testing for cycle tyres. This standard includes the overall dimension determination method and the static loaded performance testing method for cycle tyres.
This standard is applicable to pneumatic cycle tyres.
This standard is not applicable to tubular racing-car tyres 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 (including any amendments) applies.
GB/T 1702 Cycle tyres
GB/T 6326 Tyre terms and definitions
GB/T 7377 Series of cycle tyres
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
3 Terms and definitions
For the purpose of this document, the terms and definitions specified in GB/T 6326 apply.
4 Test equipment and precision
4.1 Supporting platform
4.1.1 The surface of the supporting platform shall be of smooth steel, with the width exceeding the overall width of the inflatable section of tested tyre.
4.1.2 The loading capacity of tester loading device shall not exceed 2000kg.
4.1.3 The displacement and pressure display precision of tester shall be ±1% of the full measuring range.
4.2 Inflation pressure gauge
The maximum measuring range of pressure gauge shall meet the test requirements with a precision of ±10kPa.
4.3 Measuring appliance
4.3.1 Steel tape, of which the maximum length shall be at least 3000mm with a precision of ±1mm.
4.3.2 Caliper, of which the maximum length shall be at least 200mm with a precision of ±0.05mm.
5 Test methods
5.1 Test conditions
5.1.1 The appearance quality of tested tyres shall meet the requirements of GB/T 1702.
5.1.2 Install the tested tyre on the measuring rim specified in GB/T 7377, and inflate with the air pressure specified in GB/T 7377.
5.1.3 Put the assembly of tested tyre and rim at the laboratory temperature of 25±10℃, and keep for 3h at least.
5.2 Test procedures
5.2.1 Adjust the tyre kept to the recommended air pressure specified in GB/T 7377 again.
5.2.2 Measure the maximum outer circumference of the tyre with a steel tape, and calculate the outer diameter using Equation (1).
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Test equipment and precision
5 Test methods
6 Test report
Annex A (Normative) Calculation of static loaded performance
