Recalculate Tire Pressure?

[aknapp]

I found this in a tire review on Discount Tires' site:

"If your OEM tire max pressure was 44 psi max and you replace it with 51 psi max (with the same load rating), you need to scale the operating pressure as well. Say your car OEM sticker says 33 psi. The new pressure for the 51 psi max rated tire is 33*51/44 = 38.25 psi. If your new tire load rating is different then the old one you need to factor it in. Say, if your old tire was 94H (1477 lbs max) and the new one is 95H (1521 lbs max) , the calculation is 33*51/44*1477/1521 = 37.14 psi. You will get better mileage and longer tread life."

Anyone care to comment on the validity of this?

[Quicksilver]

It may be valid for some aspects of a tire but it doesn't have much to do with how we want to use our tires. Tire design is insanely complex and thinking that you can use the rated "max pressure" as a fixed point on some sort of scale is kind of silly. Doing something to get people to raise tire pressures in a safe manner isn't going to do anything bad except possibly make the ride slightly harsher.

Raising pressures will increase fuel economy and reduce the tire 's tendency to aquaplane. For the average driving public all of these things are good but we have slightly different needs. Our needs will even vary based on the alignment and what suspension pieces are in the car.

We are better off finding a chunk of asphalt where we can drive in a circle (e.g. a skid pad) and adjusting the pressures on one end to maximize grip. Then do the other end. When you are complete adjust for the push/loose balance that you prefer and you should have a setup that is good for you in your car.

Or if that is a bit more then what you want to do you could just use the numbers on the door!