Page 11 - 2016-v.1-Part 8(EN)

TBIS 4210-8:2016

4.4.1.2 Single-speed system

With the non-drive side crank in the forward position, apply a force, F 1, increasing gradually to 1 500 N
vertically downwards to the centre of the non-drive side pedal. Maintain this force for 1 min.

Should the system yield or the drive-sprockets tighten, such that the crank rotates while under load to
a position more than 30° below the horizontal, remove the test force, return the crank to the horizontal
position or some appropriate position above the horizontal to take account of yield or movement, and
repeat the test.

On completion of the test on the non-drive side crank, repeat the test with the drive side crank in the
forward position and with the force applied to the drive side pedal.

4.4.1.3 Multi-speed system

a) Conduct the tests described in 4.4.1.2 with the transmission correctly adjusted in its highest gear.

b) Conduct the tests generally as described in 4.4.1.2 with the transmission correctly adjusted in its
lowest gear but, where appropriate, with the maximum force, F 1, adjusted to suit the particular gear
ratio. Thus:

The maximum force, F 1, shall be a function of the lowest gear ratio, N c/N s,

where

F 1 is the force applied to the pedal, expressed in newton (N);
N c is the number of teeth on the smallest chain wheel (front);

N s is the number of teeth on the largest sprocket (rear).

Where the ratio N c/N s has a value equal to or greater than 1, the force, F 1, shall be 1 500 N; but where
the ratio N c/N s has a value less than 1, the force, F 1, shall be reduced in proportion to the lowest gear
ratio. Thus:

F 1 is 1 500 × N c/N s.

4.4.2 Test method for drive system with belt

The sample in its fully finished condition (with teeth, if any) shall be submitted to a water spray
conditioning equivalent to IPX4 specified in IEC 60529:2001, 14.2.4 during 10 min. Application of the
loading shall be done within 20 min after conditioning.

a) If the drive system is a single-speed system, conduct the tests as described in 4.4.1.2.

b) If the drive system is a multi-speed system, conduct the tests as described in 4.4.1.3.

4.5 Drive belt — Tensile strength test

Set up a fixture with two drive pulleys that are similar or identical as shown in Figure 5. At least one
pulley should be free to rotate. Increase the tensile load gradually until the tension load of the belt
reaches 4 000 N.

NOTE 4 000 N is the tension load within the belt and requires a load F of 8 000 N to achieve this tension load.

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