Page 11 - 2016-v.1-Part 9(EN)

TBIS 4210-9:2016

4.5 Seat-post — Fatigue test and static strength test

4.5.1 General

In the following test, if a suspension seat-post is involved, the test shall be conducted with the suspension
system adjusted to give maximum resistance.

4.5.2 Test method for stage 1 (fatigue test)

A seat-post shall be inserted to the minimum insertion depth (as specified in TBIS 4210-2:2016,
4.16.2) in a suitable fixture with a representative seat collar and clamped to the manufacturer’s
recommended torque. The seat-post shall be fixed at an angle of 73° from horizontal, as shown in
Figure 5.

Secure an extension-bar to the saddle attachment point by the appropriate attachment fitting such
that the bar extends rearwards and downwards at an angle of 10° below the horizontal to permit the
application of a vertical test force at a distance of 70 mm from the centre of the saddle clamp where the
centreline of the clamp intersects the axis of the bar, as shown in Figure 5.

4.5.2.1 Fatigue test stage 1
Apply a repeated, vertically downward, dynamic force of stage 1 F 3 to the point described above
and shown in Figure 5 for 120 000 cycles. The forces are given in Table 2. The maximum test
frequency shall be maintained as specified in TBIS 4210-3:2016, 4.5.

4.5.2.2 Fatigue test stage 2
Apply a repeated, vertically downward, dynamic force of stage 2 F 3 to the point described above
and shown in Figure 5 for 100 000 cycles. The forces are given in Table 2. The maximum test
frequency shall be maintained as specified in TBIS 4210-3:2016, 4.5.

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