65
e
f
g
h
Valves
There are two valve types in general use on mountain
and cross bikes:
1.
Sclaverand
or
Presta valve
(d)
: This valve is nowa-
days used on almost all types of bikes. It is designed
to withstand extremely high pressures.
2.
Schrader
or
American valve
(e)
: This is an adapted
car tire valve.
All valve types come with a plastic cap to protect them
from dirt.
The
Schrader valve
can be inflated with a suitable pump
directly after removing the protective cap.
With
Presta valves
you first have to undo the small
knurled nut a little and depress it carefully until air starts
to escape. Check the valve core is tightened and seated
in its stem, otherwise air may slowly leak out. Do not
forget to tighten by hand the valve nut after inflating.
Tires with
Schrader valves
can conveniently be inflated
at car filling stations with a compressed air dispenser.
The same applies to Presta valves fitted with a special
adapter. A compressed air dispenser must be used very
carefully in short bursts as you may otherwise overin-
flate the tire and make it burst. To let out air, press the
needle in the center of the Schrader valve or the knurled
nut of the Presta valve
(f)
.
It can be hard to inflate tires to the necessary pressure by
using hand pumps. It is much easier with a track pump
equipped with a pressure gauge
(g)
.
Rim trueness and spoke tension
For the true running of the wheel it is imperative that
the tension exerted by the spokes is distributed evenly
around the rim. If the tension of a single spoke changes,
e.g. as a result of riding fast over a kerb or of a loose
nipple, the tensile forces acting on the rim become un-
balanced and the wheel will no longer run true. The
functioning of your MERIDA bike may even be impaired
before you notice the wobbling appearance of a wheel
that has gone out of true.
With rim brakes the sides of the rims also serve as brak-
ing surfaces. An untrue wheel can impair your braking
effect. It is therefore advisable to check the wheels for
trueness from time to time. For this purpose lift the
wheel off the ground and spin it with your hand. Watch
the gap between the rim and the brake pads. If the gap
varies by one millimeter or more, you should ask your
MERIDA dealer to true up the wheel
(h)
.
G
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 normally instantly jams the wheel
and throws you off your bike.
A
Loose spokes must be tightened at once. Oth-
erwise the load on the other spokes and the
rim will increase.
A
Truing (retruing) wheels is a difficult job
which you should definitely leave to your
MERIDA dealer.
Summary of Contents for BIG.NINE E-LITE 600
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