At 7:58 PM -0400 6/17/04, Douglas Morris wrote:
>Okay, what's the word on appropriate tire pressures for tire sizes different
>from stock?
>e.g. do 205/70s require different pressures from those required in the
>owners' manual?
The short answer is no, you should use the same pressures. The
explanation is a bit longer. Tire pressure is expressed in pounds per
square inch. Your car weighs 2000 pounds (for the sake of this
exercise). If you use 30 PSI in your tires, you'll have a total
contact patch of 66.7 square inches between the four tires,
regardless of the size or aspect ratio. You can jigger the handling
of the car with tire pressure. More pressure decreases rolling
resistance and steering effort.
There are plenty of other handling effects related to tire pressure,
but I won't go into them. Generally, I use 3-5 PSI over the
recommended pressure to tighten up the handling, regardless of tire
size, on all my cars.
--
Phil Barnes (peb3@cornell.edu)
Cortland, NY (nowhere near New York City)
'71 TR6 CC61193L (27 year owner)
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