Page 32 - 2017-v.2-Part 4(EN)

4.7 Brakes — Heat-resistance test

Drive the wheel and tyre assembly with the brake applied on a machine such as those described in
4.6.5.5 at a velocity of 12,5 km/h ± 5 % with a rearward, cooling air-velocity of 12,5 km/h ± 10 %, so
that a total braking energy of E Wh ± 5 % specified in Ta ble 1 is developed. The duration of the test shall
be 15 min ± 2 min.

Allow the brake to cool to ambient temperature and then repeat the test cycle.

A maximum of 10 interruptions per test cycle is permitted, each with a maximum duration of 10 s.

When the test has been carried out, subject the brakes to the applicable parts of the tests described in
4.6.5.7 item c) 1) and 2).

Calculate the braking energy from Formula (5):

E = F Br × V Br × T (Wh)
(5)

where

F Br is the braking force (N);

V Br is the linear velocity of the periphery of the tyre (i.e. 12,5 km/h = 3,472 m/s) (m/s);

T is the duration of each test cycle (excluding interruptions) (i.e. 15 min = 0,25 h) (h).

Table 1 — Total braking energy

City and trekking Young adult bicy-
Bicycle type Mountain bicycles Racing bicycles
bicycles cles
Total braking
energy, E 55 55 75 75
Wh

When the test has been carried out, the brakes shall be subjected to the applicable parts of the test
described in 4.6.5, in order to check that the requirement in TBIS 4210-2:2017, 4.6.9.2 is fulfilled.

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