Originally posted by Matt R:
The pressure printed on the side of the tire is the maximum safe tire pressure, not what you should be running. The pressure inside the tire should never match or exceed the pressure printed on the side.
This is basically correct. Running 41 lbs on a tire that has a maximum of 41 lbs listed on the sidewall is insane. It will ride rougher than a truck and the center portion of the tread will wear out way too fast while leaving reasonable tread on the outside edges.
The sidewall maximum is a cold reading. It can go above that when hot. It would only be appropriate when the car has a heavy load or when the tire is undersized for the car.
Often, the tire maker will have a recommended tire pressure. It may be found in their catalog. Usually I pay attention to the tire makers suggestions and the automakers suggestions and come up with my own, which I alter as the tire wears as well as from experience as I drive. Most of the time I start with about 2 lbs above the automaker's recommendations.
As the tire wears you can see if it is wearing evenly across the face of the tire. If it is wearing more toward the center of the tread, lower the pressure a little. If the outside edges are wearing more, raise the pressure a little.
Usually you will use a little more pressure on the street than you will on the track autoX.
Jim Johnson
98 SVT
03 Escape Limited
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