Page 21 - TBIS_79010-2019_(EN)_1nd

TBIS 79010:2019

4.2.2.9.3.2 Symbols
F 0p
Operating force (i.e. force applied on brake-lever or pedal)
F 0p intend
Intended operating force (e.g. 40 N, 60 N, 80 N etc.)
F 0p rec Recorded operating force (e.g. 38 N, 61 N, 79 N etc.)
F Br
Braking force
F Br rec
Recorded braking force
F Br corr
Corrected braking force (Corrected for difference between F Op intend
and F Op rec)
F Br average
The arithmetic mean of the three F Br corr at one level of F Op intend
F Br max
The maximum F Br average
D
F Br
Dry braking-force
W
F Br
Wet braking-force

4.2.2.9.3.3 Test machine
The test machine shall incorporate a system that drives the wheel under test by tyre
contact and a means of measuring the braking-force, and typical examples of two

types of machine are illustrated in Figure 6.
Figure 6 shows a machine in which a roller drives the individual wheels, Other types
of machine are permitted, provided they meet the specific requirements listed
below.
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 4 — shall be provided, with the width of the contact on the lever not greater
than 5 mm. In the case of back-pedal brake, a means of applying forces to a pedal
is also required.

4.2.2.9.3.4 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 6, for example), accurate to
within ± 5 %;

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