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In the 80's, the Society of Automotive Engineers
published a paper authored by BF Goodrich tire
engineers.
A brief summary of the key points follows.
ROLLING RESISTANCE/FUEL ECONOMY:
The lower the air pressure in a tire, the
higher the rolling resistance.
Having the right air pressure in a tire
lowers the rolling resistance.
The point here is that running a tire with
low air pressure makes it harder to push down the
road and increases fuel consumption.
TREAD WEAR:
Proper inflation decreases wear on a tire.
Too little air wears both edges off a tire.
Too much air wears the middle out of it.
Today’s radial tires are much more sensitive
to under-inflation than they are to over-inflation.
Considering all factors, a little too much air is
better than too little.
ALL TIRES LOSE AIR:
There isn’t a tire made that doesn’t lose a
little air pressure throughout its life, some faster
than others.
Sometimes it’s the valve stem or the rim or
the sealing bead area that actually causes the loss
but the important thing is to check your tires
periodically to make sure they haven’t lost
pressure.
BRUISE RESISTANCE:
Here is one area that runs counter to all
others.
The higher the air pressure the greater the chance
of damaging a tire due to impact with sharp objects.
If you know you will be driving in “off road”
conditions, reduce the air pressure by a few psi to
protect them.
Two cautions though: this increases the
exposure of the more delicate sidewall of the tire
to obstacles and don’t forget to re-inflate your
tires when returning to smooth pavement.
VEHICLE HANDLING:
Increasing air pressure generally increases
handling performance for two reasons.
The firmer tire responds more quickly to
steering input and also keeps the tread more firmly
planted on the pavement instead of rolling under the
wheel on turns.
Air pressure also affects “aligning torque”
or the force that causes a car to track in a
straight line.
Too much pressure reduces that force and
tends to “lighten” the steering feel.
If you change your pressure much, carefully
check the handling change.
HEAT BUILDUP:
Very important...a tire with too little
pressure, especially at high speeds will get very
hot and may disintegrate. This could be extremely
dangerous at freeway speeds.
PROPER AIR PRESSURE IS SAFER AND SAVES YOU MONEY!
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