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When tested by the method described in TBIS 4210-8:2016, 4.4.1, there shall be no fracture of
any component of the drive system and drive capability shall not be lost.

b) Drive system with belt

When tested by the method described in TBIS 4210-8:2016, 4.4.2, there shall be no fracture of
any component of the drive system and the belt shall not slip/skip, fracture, or cause any loss in
drive capability.

Smooth sliding between pulleys and belt is allowed at a rate not exceeding 1°/s at the drive axis.

4.13.7 Crank assembly — Fatigue test

4.13.7.1 Requirement

When tested by the method described in TBIS 4210-8:2016, 4.6.2, there shall be no fractures or
visible cracks in the cranks, the bottom-bracket spindle, or any of the attachment features, or
loosening or detachment of the chain wheel from the crank.

For composite cranks, the running displacements (peak-to-peak values) of either crank at the point where
the test forces are applied shall not increase by more than 20 % of the initial value (see TBIS 4210-
3:2016, 4.6).

4.13.7.2 Special requirements for mountain bicycles

For mountain bicycles, two types of fatigue test are specified, one with the cranks positioned at 45° to
the horizontal to simulate the forces due to pedalling, and the second test with the cranks positioned at
30° to the horizontal, which has been found to simulate the forces due to the rider standing on the pedals
during the descent of hills. The two tests shall be conducted on separate assemblies.

When tested by the method described in TBIS 4210-8:2016, 4.6.3, there shall be no fractures or
visible cracks in the cranks, the bottom-bracket spindle or any of the attachment features, or
loosening or detachment of the chain wheel from the crank.

For composite cranks, the running displacements (peak-to-peak values) of either crank at the point where
the test forces are applied shall not increase by more than 20 % of the initial value (see TBIS 4210-
3:2016, 4.6).

4.14 Drive-chain and drive belt

4.14.1 Drive-chain

Where a chain-drive is used as a means of transmitting the motive force, the chain shall operate over the
front and rear sprockets without binding.

The chain shall conform to the tensile strength and push-out force requirements of ISO 9633. But the
tension strength of racing bike should higher than 9000 N, and record the yield point and Max. strength
value and push-out force during the test,.

4.14.2 Drive belt

Where a belt-drive is used as a means of transmitting the motive force, the drive belt shall operate over
the front and rear pulleys without binding. When tested by the methods described in TBIS 4210-
8:2016, 4.5, there shall be no evidence of cracking, fracture, or delamination of the belt drive.

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