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Table 6 — Forces on loading attachment
Forces in newtons
City and trekking Young adult
Bicycle type bicycles bicycles Mountain bicycles Racing bicycles
Force, F5 1 000 1 000 1 500 1 200
5.4 Front fork — Rearward impact test
5.4.1 Test method 1
5.4.1.1 Stage 1 Rearward impact test
Mount the fork according to Annex B as shown in Figure 7. Assemble a roller of mass less than or equal to
1 kg and with dimensions conforming to those shown in Figure 8 in the fork. The hardness of the roller
shall be not less than 60 HRC at impact surface.
Rest a striker of mass 22,5 kg ± 0,1 kg on the roller in the fork dropouts such that it is exerting a force
against the direction of travel and in the plane of the wheel. Position a deflection measuring device
under the roller and record the position of the roller in a direction perpendicular to the axis of the fork
steerer and in the plane of the wheel and note the vertical position of the fork.
Remove the deflection measuring device, raise the striker through a height of h 4, and release it to strike
the roller against the rake of the fork. The drop heights are given in Ta ble 7. The striker will bounce and
this is normal. When the striker has come to rest on the roller, measure the permanent deformation
under the roller.
If the fork meets the requirement as specified in TBIS 4210-2:2017, 4.9.2, and conduct stage 2 of the
test with the assembly in the same mountings.
NOTE See TBIS 4210-3:2016, Annex B.
5.4.1.2 Stage 2 Static energy absorption
Mount the fork according as in 5.4.1.1, apply a progressively increasing force in the same position and
direction as in 5.4.1.1, until the energy is 1.2 time as 5.4.1.1(Table 7). The displacement rate is 15
mm/min
Table 7 — Drop heights
Dimensions in millimetres
City and trek- Young adult Mountain bicy-
Bicycle type Racing bicycles
king bicycles bicycles cles
Stage 1 Forks made 180 180 360 360
Drop entirely of metal
height, Forks which have 320 320 600 640
h4 composite parts
Stage 2 Forks made
Static entirely of metal 47.6 47.6 95.3 95.3
energy Forks which
absorption, have composite 84.7 84.7 158.8 169.3
J parts
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