Tires: Aftermarket tire pressure, scion xa, tyre pressure

Question
Hi,
I have sedan similar like scion xa, with original tire is 175/65/R14 82H. The original tire pressure is 33 psi for front and 30 psi rear. I have changed the tire with 195/55/R15 85W. So please advise what is the correct pressure for the new tyre ? Must the tyre pressure not increase more than 4 psi after driving still valid for this tyre ?


Regards,
George

Answer
George,

You could use 3 psi lower, but since you'll want to protect the rims, why not leave the pressure the same?

I think your second question concerns pressure build up.  That is a good way to tell if the specified pressure is too low, but it isn't a good way to tell if it is correct.

Pressure build is due to heat and you want to limit the amount of heat the tire is generating.  But heat isn't the only thing important in deciding what pressure to use.  Normally you don't want to see  more than to 3 to 5 psi buildup.  If you experience more than that, you need more pressure.