Page 11 - 2016-v.1-Part 5(EN)

TBIS 4210-5:2016

Dimensions in millimetres

a) Orientation of adjustable handlebars b) Position of applied forces

Key
1 clamping fixture

Figure 4 — Handlebar and stem assembly — Lateral bending test for racing bicycles

4.4 Handlebar stem — Forward bending test

4.4.1 Test method for stage 1

For stems which have a quill for insertion into a fork steerer, clamp the quill securely in a fixture to the
minimum insertion depth, or for stem extensions which clamp directly on to an extended fork steerer,
clamp the handlebar stem extension securely on to a suitable, solid-steel bar and clamp the bar in
securely in a fixture, the projecting length of the bar not being critical.

Apply a force of F 3 through the handlebar attachment point in a forward and downward direction and
at 45° to the axis of the quill or steel bar as shown in Figure 5 and maintain this force for 1 min. The
forces are given in Ta ble 3. Release the test force and measure any permanent deformation as specified
in TBIS 4210-2:2016, 4.7.6.3.2.

If the handlebar stem meets the requirement of TBIS 4210-2:2016, 4.7.6.3.2, conduct stage 2 of the
test.

Table 3 — Forces on stems

Forces in newtons

City and trekking Young adult
Bicycle type bicycles bicycles Mountain bicycles Racing bicycles
Stage 1 Force, F 3 1 600 1 600 1 600 1 600
Stage 2 Force, F 4 2 000 2 000 2 600 2 300

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