[Suby Fan]

Originally Posted by NikFu S.

I use the numbers on the tire itself, which are around 40psi, but if I had stock diameter tires I would still use the tire's numbers.

You can always eyeball the sidewalls to see if your pressure is good.

Ohh ok ohh boy i deal with this every day at my tire shop...

1. NEVER inflate your tire to the pressure it says on the tire! that is a very bad idea... early seporation will occor that number is the MAX the tire it self can handle

2. you can NOT tell by eyeballing the side wall that is a bad idea that leads people to fill their tires with 60+ pounds of air (no joke i see it once a week)

3. dont even think of going over 35 psi unless you own a 3/4 ton truck when your tires get hot the pressure can increase to over 40 psi (the max psi the tire can handle.. at this point a blow out may occur)

IF you really think the stock tire pressure is inacurate then there is a test that can be done

put a puddle of water down on a level surface like a drive way or parking lot start with the stock recomendations and drive over the water.. messure the tred width it should match up with the width of the tire (225 mm) if its too wide add air and repeat if its too narrow drop the pressure and repeat.. do the same thing with the back tires.. this test is a little pointless because you should get the same numbers as the factory did because they ran simalir tests when figuring out proper air pressure