Page 24 - 2018-v.3-Part 2(EN)

4.9 Front fork

4.9.1 General

4.9.2, 4.9.4, 4.9.5, and 4.9.6 apply to all types of fork.

In the strength tests in 4.9.4, 4.9.5, 4.9.6, and 4.9.7, a suspension fork shall be tested in its free,
uncompressed length condition.

4.9.2 Means of location of the axle and wheel retention

The slots or other means of location for the wheel axle within the front fork shall be such that when the
axle or cones are firmly abutting the top face of the slots, the front wheel remains central within the
fork.

The front fork and wheel shall also fulfil the requirements of 4.10.4 and 4.10.5.

4.9.3 Suspension forks — Special requirements

4.9.3.1 Tyre clearance test

When tested by the method described in TBIS 4210-6:2017, 5.1, the tyre shall not contact the crown of
the fork, nor shall the components separate.

4.9.3.2 Tensile test

When tested by the method described in TBIS 4210-6:2017, 5.2, there shall be no detachment or
loosening of any parts of the assembly and the tubular, telescopic components of any fork-leg shall
not separate under the test force.

4.9.4 Front fork — Static bending test

When tested by the method described in TBIS 4210-6:2017, 5.3, there shall be no fractures or
visible cracks in any part of the fork, and the permanent deformation, measured as the displacement of
the axis of the wheel axle, or simulated axle in relation to the axis of the fork steerer, shall not exceed
10 mm and record the ratio between weight and rigidity in the test result.

4.9.5 Front fork — Rearward impact test

4.9.5.1 Forks made entirely of metal

When tested by the method described in TBIS 4210-6:2017, 5.4.1, if there are any fractures or
visible cracks in any part of the fork, and the permanent deformation, measured as the displacement of
the axis of the wheel axle or simulated axle in relation to the axis of the fork steerer, exceeds 45 mm,
the fork shall be considered to have failed.

If the fork meets the first test criteria, then it shall be subjected to a second test as described in
TBIS 4210-6:2017, 5.4.2, after which it shall exhibit no fractures. If the fork meets the first and
second test criteria, then it shall be subjected to a third test as described in TBIS 4210-6:2017, 5.4.3,
irrespective of the amount of permanent deformation, there shall be no relative movement between
the steerer and the crown.

4.9.5.2 Forks which have composite parts

When tested by the method described in TBIS 4210-6:2017, 5.4.1, there shall be no fractures in any
part of a fork, and the permanent deformation, measured as the displacement of the axis of the wheel
axle or simulated axle in relation to the axis of the fork steerer, shall not exceed 45 mm. If the fork meets
the first test criteria, then it shall be subjected to a second test as described in TBIS 4210-6:2017, 5.4.3.
Torque on
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