Page 27 - 2017-v.2-Part 4(EN)

The specific requirements are as follows:

a) the linear surface velocity of the tyre shall be 12,5 km/h and shall be controlled within ±5 %;

b) a means of laterally restraining the wheel under test shall be provided which does not influence the
measurement of braking force;

c) a means of laterally applying forces to the brake levers at the point specified in Figure 5 shall be
provided, with the width of the contact on the lever not greater than 5 mm. In the case of back-pedal
brakes, a means of applying forces to a pedal is also required.

4.6.5.5 Instrumentation

The test machine shall be instrumented to include the following:

a) a device to record the surface velocity of the tyre, accurate to within ±2 %;

b) a device to record the braking force (see Figures 14 and 15, for example), accurate to within ±5 %;

c) a device to record the operating force applied to the hand lever or pedal, accurate to within ±1 %;

d) a water spray system, to provide wetting of the brakes of the bicycle, consisting of a water reservoir
connected by tubing to a pair of nozzles arranged as shown in Figure 16. Each nozzle shall provide a
flow of water at ambient temperature of not less than 4 ml/s. The wheel shall be suitably enclosed to
ensure that, in addition to the rim, any hub- or disc-brake is thoroughly wetted before a test begins;

e) a system for loading the wheels of the bicycle against the driving mechanism (see 4.6.5.6).

Dimensions in millimetres

a) Testing the front brake b) Testing the rear brake

Key
1 braking force transducer
2 applied force
3 additional mass
4 direction of drum rotation

Figure 14 — Braking performance test machine — Single drum type

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