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TIRE MAINTENANCE Proper air pressure is critical to maintain
vintage road bicycle wheels!
Clincher tires use air pressure, coupled with
tire and rim design features, to secure a tire in place. When air is used
to pressurize the tire, the tire's "bead", or special edge, is forced into/under
the special "curled" edge of the wheel rim. Under pressure, these two
features work together to "clinch", or hold, the tire/tube in place. Now,
this "clinching action" works best when tire air pressure is optimal.
And optimal air pressure is usually defined as a range between high and low,
with that information embossed on the tire itself.
Inadequate air
pressure, the Ten Speed's most common malady, will allow the tire to creep around the rim, as the bicycle accelerates
and decelerates. When you see a valve stem that is sitting an an awkward
angle, it usually means that the wheel was ridden, quite often, with inadequate
air pressure. If you see the crooked valve, look immediately for flat
spots on the rim. Inadequate air pressure can, and WILL lead to inner tube
failure (pinched inner tube) and rim damage (flat spots and/or dents)!
The following is the BIG secret to avoiding road bicycle flat tires and rim
damage. Keep the tires properly pressurized when in use. Always
ensure that the pressure is close to, or right on, maximum. As mentioned,
the max air pressure will be indicated on the tire.
When I mount tires, I always place the tire pressure information right beside
the inner tube valve stem. This helps me find what pressure to use, with
which bicycle, something that can cause confusion, when one owns several.
BABY POWDER: In addition to proper tire pressure, baby powder (talc)
can be used to help prevent tire and inner tube creep. Before installing
the inner tube, place it in a plastic bag, containing some baby powder.
Close the top and shake the bag up, ensuring that he inner tube is completely coated with a light patina of
powder. Now, the inner tube can be installed. I should add that this
baby powder will actually facilitate the tire installation, allowing the
tire to slide into place, on the rim, with much greater ease.
Next time a flat tire comes your way, and if the inner tube is beyond repair,
take the time to cut the inner tube in half. Guess what you will find
inside? Some white powdery stuff that looks and feels just like baby powder.
The baby powder does a couple of other good things, both of which prevent
creep and inner tube wear. The powder acts as a lubricant, preventing the
inner tube from sticking to the tire which can, and likely will, happen over
time. Once the inner tube/tire bond is formed, creep becomes inevitable.
Additionally, the tire and tube actually rub against one another during use.
Sooner or later, this rubbing together will cause wear and it will most
likely be the inner tube that wears out first. By reducing the harshness
of this rubbing action (adding lubricant), wear will be reduced, fewer flat
tires will result and the inner tube will have an extended life. Not bad
for that powder that makes babies smell so good.
HAPPENS TO THE BEST OF US: When pressurizing a tire, do so slowly and
keep an eye on what you are doing. Try to determine if the tire is fitting properly into the rim curl. This
can usually be seen by taking a look at tire markings, one of which will be a
line of sorts all the way around both sides of the tire. If this looks to
be uneven when compared to its relationship to the rim, trouble will follow. It usually means that the inner tube is
trapped between the "bead" of the tire and the curl of the rim.
Sooner or
later this will result in a puncture or, worse yet, slipping out of the
"bead/rim fit". When this "fit" or "clinch" slips, there will be a big bang. The
bead will slip past the curl, allowing the highly pressurized inner tube to
extrude rapidly and KAPOW! The
inner tube will burst!
The sudden and violent movement might even destroy the bead on the tire,
rendering it useless.
Of course, your riding habits will
have much to do with your tire's performance, when reliability and
durability are the issues. If you are not prone to watching the
road, as you ride, then chances are you will hit more debris that
someone who does look at the road. I do not mean look just ahead
for traffic concerns. Look down at the road you are about to roll
over. And do not roll over things that will flat your tire or
damage your rims.
NEXT - RIM MAINTENANCE |
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