Bicycle Tubes: Presta Valves
Bike Tire Tube Stems
A bike tire tube stem is the small metal valve on typical bicycle
tubes that allows you to attach a pump and fill up your tire
with air. The tube stem typically comes in two different designs,
each with its own set of advantages.
Presta Bicycle Tube Valves:
is the slimmer newer redesign of the tube stem. A Presta Valve
requires a smaller hole in the bike rim causing less impact on
the overall strength of the rim. The older Schreader valves with
their larger stem diameters required manufacturer to stay with
wider rims to maintain stiffness and strength around the port
hole. A presta bicycle tube valve solves that problem offering
greater flexibility in design.
For this reason presta valves are typically used on higher end
mountain bike rims and on all slim line road bikes. For competitive
bikers looking for every edge, these valves are also much more
aerodynamic and are less likely to unbalance the wheel.
Some presta bike tube valves do have a removable valve core,
which is necessary if you would like to use tire sealant product
and fill it on your own. The word on the street though is that
these double screw-in valves have a bad habit of coming loose
and require a set of pliers for onroad repairs. Thus I'd avoid
the whole story by buying prefilled self sealing tubes or stay
with the regular ones and use tire liners for puncture protection.
fill a tube via a presta valve, you must use an adapter in order
to use a common gas bar pump. This adapter can be left on the
rim if you are likely to forget it at home and don't usually bring
a pump with you on your rides. But this may kind of counteract
some of the advantages of using a presta valve by adding more
weight to the outer circumference of the wheel and increase the
power needed to initial accerleration.
Presta valves do require less effort during inflation because
there is no spring holding the valve closed as with Schraeder
valves. They are better at holding the higher pressures found
in road tires, and less prone to leaking.
It is important to remember that the types of bike tire tube
stem can affect robustness. A presta valve is much more fragile
than a Schraeder valve and therefore extreme care must be taken
during filling so that it does not get snapped off. Carrying a
replacement tube is essential. It is impossible to fix a tube
stem, and no fun if you have to push your bike five miles out
of the bush.
More Articles of Interest:
Bicycle Tubes and Their