Felt Bicycle - Stems for Threadless Systems, the Aheadset* System

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Stems for threadless systems, the Aheadset* system
(*Aheadset is a registered trade mark of the Dia-Compe company which invented
the threadless fork tube system.)
On bikes with an Aheadset the stem also serves to adjust the initial headset bearing
pressure. If you change the position of the stem, you have to readjust the bearings
(see the chapter “The headset”). The vertical setting range is determined by the
intermediate rings, also referred to as spacers. In the case of flip-flop stem models
it is also possible to mount the stem the other way round to achieve a different
handlebar height.
Release the bolt at the top of the fork tube which serves to adjust the initial bearing
pressure and remove the Ahead cap (a).
Release the bolts on either side of the stem and pull the stem off the fork. Now you
can remove the spacers (b).
You can determine the handlebar height by the arrangement of stem and spacers.
Slip the remaining spacers onto the fork tube above the stem.
If you want to turn the stem around, you also have to release the bolts securing the
handlebars. If the stem is fitted with a cap, you can simply take out the handlebars
at this point. If it is not fitted with a cap, you have to remove the handlebar fittings
(see the instructions in the chapters further below).
If the stem is turned around, it is possible, that the cables are too short. In
this case riding can be unsafe. Ask your FELT dealer for help.
After turning the stem around, centre the handlebars and tighten the bolt again.
Readjust the bearing (c), align the stem and then tighten it (see the chapter “The
headset“) (d).
Check whether the handlebars are firmly seated in the stem by trying to rotate
the handlebars downwards. Also check whether the handlebar/stem unit can be
twisted relative to the fork. Do this by holding the front wheel between your knees
and trying to twist the handlebars. If there is movement, carefully tighten the bolts a
little more and check again. Do not go beyond the maximum permissible torque!
When completely removing the spacers you will have to shorten the fork
tube. This change is irreversible and in any case best left to an expert.
When you are sure of the position you want, ask your dealer to do the
job for you.
ii
a b c d