[Lanny]

Tires, like most everything else, evolve and have improved over the years, so
the recommendations listed in your old car handbook, were for the tires made
at that time. Many of the new radials have a Max pressure of 44 and even 51#'s.

Look at the recommendations that the tire manufacture puts right on the tire,
and I generally run a few pounds less than the Max listed on the tire.
Use some common sense on how much less, generally 4 to 8#'s less, depending
on the weight of your car, and a couple #'s less in the rear than the front.

Here is an article about under inflated tires.

Driving on under-inflated tires is dangerous. According to the National
Highway Traffic Safety Administration, almost 1/3 of passenger cars, light
trucks and SUVs are being driven with at least one under-inflated tire.

Under-inflation is one of the leading causes of tire failure. If tire pressure
is too low, too much of the tire’s surface area touches the road, which
increases friction. Increased friction can cause the tires to overheat,
which can lead to premature wear, tread separation and blowouts.




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