Page 30 - 2017-v.2-Part 4(EN)

of 200 N ± 10 %. Maintain this operating force for at least 2,5 s, and note the value of the applied
operating force.

Repeat the procedure (applying the operating force determined in the paragraph above accurate
to within ±5 %) 10 times, or with more repetitions if necessary, until the mean braking force from
anyone of the three latest tests does not deviate by more than ±10 % from the mean braking force
from these same three tests.

c) The performance tests

1) Testing under dry conditions

For hand-operated brakes, with a vertical force applied to the bicycle sufficient to prevent
skidding of the tyre on the wheel under test, accelerate the driving mechanism to the specified
velocity, then apply the operating force in a series of 20 N increments from 40 N to either 180 N
(in case of young adult bicycles, apply to 120 N) or to the force necessary to achieve a braking
force of at least 700 N, whichever is the lesser. However, if the wheel locks, if any possible brake-
overload device is actuated, or if the hand lever comes into contact with the handlebar, do not
increase the force further. For each increment of applied operating force, perform three tests
within 1 min. Before applying the next level of operating force, allow the brake to cool for 1 min.

For back-pedal brakes, with a vertical force applied to the bicycle sufficient to prevent skidding
of the tyre on the wheel under test, accelerate the driving mechanism to the specified velocity,
then apply the operating force in a series of 50 N increments from 100 N to either 350 N or to
the force necessary to achieve a braking force of at least 400 N, whichever is the lesser. However,
if the wheel locks, if any possible brake-overload device is actuated, do not increase the force
further. For each increment of applied operating force, perform three tests within 1 min. Before
applying the next level of operating force, allow the brake to cool for 1 min.

The applied operating forces shall lie within ±10 % of the intended operating forces, shall be
applied as specified in Figures 5 and 6 and 4.6.5.4 item c), shall be recorded with an accuracy of
±1 %, and shall be fully applied within 1,0 s of the commencement of braking.

For each increment of operating force, record the braking force value, F Br rec, for a period of
between 2,0 s and 2,5 s, with measurement starting 0,5 s to 1,0 s after the commencement of
braking. Record F Br rec as the average braking force during this measurement period.

The time at which the measurement of the braking force is started shall be related to the
speed at which the operating force is applied. If the operating force is fully applied in less than
0,5 s after the commencement of braking, start the measurement after 0,5 s. However, if the
operating force is fully applied between 0,5 s and 1,0 s after the commencement of braking,
start the measurement when the operating force is fully applied.

2) Testing under wet conditions

The method shall be as given in 4.6.5.7 item c) 1) with the addition that wetting of the brake
system shall commence not less than 5,0 s before the commencement of braking and shall
continue until the measurement period has ended.

Water nozzles shall be arranged according to Figure 16.

d) Correction of braking force

Each recorded braking force, F Br rec, shall be corrected for any difference between the recorded
operating force and the intended operating force. The corrected braking force shall be calculated by
multiplying the recorded braking force, F Br rec, with a correction factor which is the ratio between
the intended operating force, F Op intend, and the recorded operating force, F Op rec.

EXAMPLE Recorded braking force F Br rec = 225 N

Intended operating force F Op intend = 180 N

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