Tires And Tubes - MARIN Bicycle Owner's Manual

Suspension can increase control and comfort by allowing the wheels to
better follow the terrain. This enhanced capability may allow you to ride
faster; but you must not confuse the enhanced capabilities of the bicycle
with your own capabilities as a rider. Increasing your skill will take time
and practice. Proceed carefully until you have learned to handle the full
capabilities of your bike.
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 specifications, ranging
from general-purpose designs to tires designed to perform best under very
specific 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 specific recommended use,
are marked on the sidewall of
the tire (see fig. 17). The part of
this information which is most
important to you is Tire Pressure.
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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 inflate 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. Inflating 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 sufficiently to pinch
the inner tube between the rim and the riding surface.
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 inflate your tires to that
pressure. Then, check inflation as described in Section 1.C so you'll know
how correctly inflated 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 fitting
appropriate to the valve stems on your bicycle.
The Schraeder valve (fig. 18a) is like the valve on a car tire. To inflate a
Schraeder valve tube, remove the valve cap and clamp the pump fitting
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 (fig. 18b) has a narrower diameter and is only
found on bicycle tires. To inflate 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 inflate. To inflate a Presta valve with a Schraeder
pump fitting, 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 fits into the Schraeder pump fitting. Close the valve after
inflation. 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.
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