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G. Tires and Tubes
1. Tires
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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. 15). 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.
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.
Fig.15
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