GB/T 41876-2022Technical specification of cured-on solid tyres (English PDF)

A.1 Measurement items

The outer circumference and section width of the tyre.

A.2 Measurement conditions

A.2.1 After the tyre is vulcanized, it shall be parked at room temperature for more than

48 h. Before testing, the tyre and rim assembly shall be parked at a temperature of

18 °C~36 °C for at least 24 h.

A.2.2 Measurement tools and their accuracy requirements are as follows:

a) Steel ruler and metal tape measure (without arc): 1 mm;

b) Vernier caliper: 0.1 mm;

c) Calipers.

A.3 Measurement methods

A.3.1 Outer circumference of tyre

Use a metal tape measure to wrap around the tyre along the centerline of the crown or near the highest point of the centerline, to measure the outer circumference. The unit of the measured values is millimeter and round up to an integer. And according to formula (A.1), obtain the outer diameter.

A.3.2 Section width of tyre

Select the widest part of the sidewall without a mark; use a vernier caliper or calipers and a steel ruler to measure the section width at four points at approximately quarters of the tyre circumference. Take the arithmetic mean. The unit of the measured values is millimeter and round up to an integer.

A.4 Calculation method

The outer diameter of the tyre is calculated according to formula (A.1).

Appendix B (Normative)

Test methods for physical-mechanical properties of tyres

B.1 General requirements

B.1.1 After the tyre is vulcanized, it shall be parked at room temperature for more than

48 h. Before testing, it shall be conditioned for at least 24 h in the standard laboratory environment specified in GB/T 2941.

B.1.2 When the surface of the sample or test piece taken from the tyre is uneven OR the thickness is greater than the corresponding standard, it shall be cut and polished according to GB/T 2941. When the thickness of the sample is less than the corresponding standard, according to the actual thickness of the sample, it can be cut into test pieces for testing.

B.2 Tests for physical-mechanical properties of tread rubber

B.2.1 Tensile properties before and after ageing

B.2.1.1 When sampling, for the tread part, take the centerline of the crown as the reference. Take samples along the longitudinal direction. If the thickness of the tread rubber is 6 mm~10 mm, cut a layer of middle-layer test piece. If the thickness of the tread rubber is more than 10 mm, cut the middle and lower two layers of test pieces.

(Special cuts for crown patterns are not limited to this).

B.2.1.2 Cut and polish the sample into a type 2 test piece conforming to GB/T 528.

Mark the position and layer of the test piece.

B.2.1.3 When the tread pattern is special AND it is impossible to cut the standard-size test piece, according to the actual situation, the clamping part of the test piece can be cut.

B.2.1.4 Carry out the tensile properties test according to GB/T 528. Carry out the tensile properties test after ageing according to GB/T 3512.

B.2.2 Hardness

B.2.2.1 Cut a sample - with a length of not less than 40 mm, a width of not less than 15 mm, and a thickness of not less than 6 mm - from the tread. Or stack up to 3 samples of the same layer to form a test piece.

B.2.2.2 According to GB/T 531.1, measure the hardness of each layer of samples. The

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