Bicycling 101: Tire Talk
by Pete Hawkins
A recent rash of tire blowouts has prompted me to write this article
in hopes of making whoever reads it more aware of the measures they can
take to help ensure against this hazard. With proper care and routine
inspection, we bikers can minimize the chance of an exploding tire ruining
our ride or much more.
As most of you hopefully know, your front tire is the most important of the
two, because of its steering function. A blowout in the back usually doesn't
cause a crash, but it takes a lot of skill and luck to avoid going down when
the front tire goes suddenly. Therefore, your front tire should get special
attention. When putting a new tire on your bike, always rotate the older front
tire to the rear, and put the new tire on the front. Make certain that you
have proper tire and rim compatibility and that the bead is properly seated.
If you don't understand the previous sentence, have a qualified mechanic show
you - it's very important.
Before each ride you should check your tires for serious nicks, cuts, and bulges.
Any damage to the side walls is always more serious than on the tread, because
the side walls are much thinner and rupture more easily. Any nick or cut in
any part of the tire that exposes the tube demands that a boot be installed
inside the tire. I suggest using one of the larger patches from your patch
kit as a boot; the inside of the tire must be thoroughly cleaned with solvent
before gluing for this to work. Any bulge in the tire indicates a cord separation;
the tire is not repairable and must be discarded.
Perhaps the most important pre-ride check is tire inflation pressure. Check
the recommended pressure stated on the side wall of every tire and do not exceed
it. I know that many riders believe that it's okay to exceed the recommended
pressure, but they are unaware of two things. First, tires are normally inflated
with cooler air, and when you are out in the sun and on very hot asphalt, the
tire pressure can increase substantially. I have witnessed many times tires
blowing up after they sat out in the sun for a relatively short period of time.
Second, the damage that occurs from over-inflation is not externally visible.
What happens is that the cords of the tire suffer small tears and become weakened.
You don't know you have a problem until you're cruising down the road and the
damaged cords start to separate and you hear a thump, thump, followed by a
very loud BANG!
This same kind of over-inflation damage can occur by putting your properly
inflated tires into a hot vehicle. Even though it's extra work, it's a very
good practice to let a significant amount of air out of your bike tires before
you put your bike in your vehicle, particularly if you plan on leaving your
vehicle in the hot sun for awhile. By doing this, you may prevent the hidden
cord damage that can cause major problems further down the road.
There are many factors that constitute bike safety; proper tire maintenance
is a significant one that with a little knowledge and diligence can be easily
achieved.
- Pete Hawkins
Copyright © 2000 Pete Hawkins. All rights reserved.
(originally published in the TCBC Activity News: August 2000)