CONSISTENCY
Without a tube, you cannot maintain consistent
air pressure. Even the slightest leakage will
cause a difference in the performance of the
tire. Therefore, if consistency is the primary
goal, as in bracket racing, a tube should always
be used.
STRENGTH
The wrinkling of the sidewall that is visible
at launch causes the carcass material in the
tire to break down over time. The more violent
the launch, the quicker this breakdown occurs.
Inconsistent 60-foot times or a drop off of
60-foot times usually indicate that this is
happening. When this happens, the tires should
be replaced, regardless of the amount of tread
rubber remaining. The use of tubes strengthens
the sidewall of the tire and keeps this breakdown
from happening prematurely, thus extending the
life of the tire. This will save you money in
the long run.
WEIGHT & PERFORMANCE
In some cases, it is acceptable to run a racing
tire without a tube. When a car competes in
a heads-up class, unsprung weight is an important
factor. Tires and tubes are all unsprung weight.
One pound of "unsprung" weight is equal to 8
pounds of "sprung" weight. The average tube
weighs about 6 pounds. Therefore, if you eliminate
the tubes, you have eliminated the equivalent
of 96 pounds from the car. For every 10 pounds
of unsprung weight removed, you may pick up
as much as .01 seconds in quarter-mile ET.
COST
All natural rubber tubes are expensive. All
M/T tubes are made of natural rubber and feature
a clamp-down valve stem. There are some inexpensive
butyl rubber tubes on the market, and even some
with clamp-down valve sterns. But natural rubber
is by far the better choice. It conforms to
the wrinkles better, dissipates heat better,
and it doesn't get brittle like butyl does.
Therefore, M/T natural rubber tubes offer superior
performance and will last far longer.
SAFETY
At a racetrack, you must check air pressure
regularly. This is important to maintain performance
and to ensure pressures are not too low. Low
pressure can be dangerous.
Never run tube-type tires on the street without
a tube. Leakage and the prolonged heat buildup
can lead to tire failure and serious injury
or death.
The bottom line is this: the decision to run
with or without tubes, Mickey Thompson folks
say, should always be based on safety and performance,
not cost.
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