Focus Bikes bicycle - Tires and Tubes

44 Focus Bicycles - Bicycle Owner’s Manual
Tech 45
CAUTION: Pencil type automotive tire gauges can be inaccurate and
should not be relied upon for consistent, accurate pressure readings.
Instead, use a high quality dial gauge.
Ask your dealer to recommend the best tire pressure for the kind of riding you
will most often do, and have the dealer inate your tires to that pressure. Then,
check ination as described in Section 1.C so you’ll know how correctly inated
tires should look and feel when you don’t have access to a gauge. Some tires
may need to be brought up to pressure every week or two, so it is important to
check your tire pressures before every ride.
Some special high-performance tires have unidirectional treads: their tread
pattern is designed to work better in one direction than in the other. The sidewall
marking of a unidirectional tire will have an arrow showing the correct rotation
direction. If your bike has unidirectional tires, be sure that they are mounted to
rotate in the correct direction.
2. Tire Valves
Thereareprimarilytwokindsofbicycletubevalves:TheSchraederValveand
thePrestaValve.Thebicyclepumpyouusemusthavethettingappropriateto
the valve stems on your bicycle.
The Schraeder valve (g. 18a) is like the valve on a car tire. To inate
a Schraeder valve tube, remove the valve cap and clamp the pump
tting onto the end of the valve stem. To let air out of a Schraeder
valve, depress the pin in the end of the valve stem with the end of a
key or other appropriate object.
The Presta valve (g. 18b) has a narrower diameter and is only found
on bicycle tires. To inate a Presta valve tube using a Presta headed
bicycle pump, remove the valve cap; unscrew (counterclockwise) the
valve stem lock nut; and push down on the valve stem to free it up.
Then push the pump head on to the valve head, and inate. To inate a
Presta valve with a Schraeder pump tting, you’ll need a Presta adapter
(available at your bike shop) which screws on to the valve stem once you’ve
freed up the valve. The adapter ts into the Schraeder pump tting. Close the
valve after ination. To let air out of a Presta valve, open up the valve stem lock
nut and depress the valve stem.
WARNING: We highly recommend that you carry a spare inner tube
when you ride your bike. Patching a tube is an emergency repair. If
you do not apply the patch correctly or apply several patches, the
tube can fail, resulting in possible tube failure, which could cause you
to loose control and fall. Replace a patched tube as soon as possible.
WARNING: Not all bicycles can be safely retrofitted with some types
of suspension systems. Before retrofitting a bicycle with any
suspension, check with the bicycle’s manufacturer to make sure that
what you want to do is compatible with the bicycle’s design. Failing to
do so can result in catastrophic frame failure.
G. Tires and Tubes
1. Tires
Bicycle tires are available in many designs and specications, ranging from
general-purpose designs to tires designed to perform best under very specic
weather or terrain conditions. If, once you’ve gained experience with your new
bike, you feel that a different tire might better suit your riding needs, your dealer
can help you select the most appropriate design.
The size, pressure rating, and on some high-performance tires the specic
recommended use, are marked on the sidewall of the tire (see g. 17). The part
of this information which is most important to you is Tire Pressure.
WARNING: Never inflate a tire
beyond the maximum
pressure marked on the tire’s
sidewall. Exceeding the
recommended maximum
pressure may blow the tire off
the rim, which could cause
damage to the bike and injury
to the rider and bystanders.
The best and safest way to inate a
bicycle tire to the correct pressure
is with a bicycle pump which has a
built-in pressure gauge.
WARNING: There is a safety risk in using gas station air hoses or
other air compressors. They are not made for bicycle tires. They
move a large volume of air very rapidly, and will raise the pressure in
your tire very rapidly, which could cause the tube to explode.
Tire pressure is given either as maximum pressure or as a pressure range. How
a tire performs under different terrain or weather conditions depends largely
on tire pressure. Inating the tire to near its maximum recommended pressure
gives the lowest rolling resistance; but also produces the harshest ride. High
pressures work best on smooth, dry pavement.
Verylowpressures,atthebottomoftherecommendedpressurerange,givethe
best performance on smooth, slick terrain such as hard-packed clay, and on
deep, loose surfaces such as deep, dry sand.
Tire pressure that is too low for your weight and the riding conditions can cause
a puncture of the tube by allowing the tire to deform sufciently to pinch the
inner tube between the rim and the riding surface.