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Appendix C
Wheel and Seat Post Quick Release Mechanisms
A. Quick Release Wheels
1. How a Wheel Quick Release Works
!
WARNING: Riding with an improperly adjusted wheel quick
release can allow the wheel to wobble or disengage from the
bicycle, causing serious injury or death to the rider. Therefore,
it is essential that you:
1. Ask your dealer to help you make sure you know how
to install and remove your wheels safely.
2. Understand and apply the correct technique for
clamping your wheel in place with a quick release.
3. Each time, before you ride the bike, check that the
wheel is securely clamped.
The wheel quick release uses a cam action to clamp the
bike’s wheel in place (see g. 19). Because of its adjustable
nature, it is critical that you understand how it works, how to use
it properly, and how much force you need to apply to secure
the wheel.
!
WARNING: The full force of the cam action is needed to
clamp the wheel securely. Holding the nut with one hand
and turning the lever like a wing nut with the other hand until
everything is as tight as you can get it will not clamp the wheel
safely in the dropouts.
a. Adjusting the quick release mechanism
The wheel hub is clamped in place by the force of the
quick release cam pushing against one dropout and pulling
the tension adjusting nut, by way of the skewer, against the
other dropout. The amount of clamping force is controlled
by the tension adjusting nut. Turning the tension adjusting nut
clockwise while keeping the cam lever from rotating increases
clampingforce;turningitcounterclockwisewhilekeepingthe
cam lever from rotating reduces clamping force. Less than half
a turn of the tension adjusting nut can make the difference
between safe clamping force and unsafe clamping force.
b. Front Wheel Secondary Retention Devices
Most bicycles have front forks which utilize a secondary
wheel retention device to keep the wheel from disengaging if its
clamping mechanism is incorrectly adjusted. Secondary retention
devices are not a substitute for correct wheel clamping.
Secondary retention devices fall into three basic categories
(seeSection4.Bgs.12a,b&c):
(1) The clip-on type is a part which the manufacturer adds
tothefrontwheelhuborfrontfork(g.12a).
(2) The integral type is molded, cast or machined into the
outerfacesofthefrontforkdropouts(g.12b).
(3) Thewashertypeisahat-shapedwasherwhichtsinto