60
. The wheels
. Rim trueness, spoke tension
The tension exerted by the spokes has to be
distributed evenly around the rim in order for
the wheel to run true. If the tension of single
spokes changes, e.g. as a result of riding fast
over a curb or because of spoke breakage, the
tensile forces acting on the rim become unbal-
anced and the wheel will no longer run true.
The functioning of your bike may even be
impaired before you notice the untrue wheel
by its wobbling.
With rim brakes the sides of the rims also
serve as braking surfaces. An untrue wheel
can impair your braking power.
It is therefore advisable to check the wheels
for trueness from time to time. For this pur-
pose lift the wheel from the ground and spin
it with your hand. Watch the gap between the
rim and the brake pads or in the case of disc
brakes between frame or fork. If the gap var-
ies by more than a millimetre, you should ask
your dealer to true up the wheel.
Do not ride with untrue wheels. In the
case of extreme side-to-side wobbles,
the brake pads of rim brakes can miss the
rim and get caught in the spokes! This nor-
mally instantly jams the wheel. Danger of
crash!
Truing wheels is a difficult job which
you should definitely leave to your
MERIDA dealer.
Check regularly the condition of the
rims. Keep in mind that the friction
generated by braking causes wear to the
rims. Once the abrasion of the rim has
reached a certain critical point, the rim can
rupture under the tire pressure. If in doubt,
ask your MERIDA dealer for advice.
