Tire pressure when +2

[BYprodriver]

Originally Posted by Auf los!

I read an article recently that suggested that when you increase your wheel size, but keep the same rolling diameter, e.g., going from stock 17" wheels to aftermarket 19", known as "+2," you should increase your tire pressure to make up for the smaller volume of air in the 19" tires. But how much? Is there a formula for this?

My 17" tire pressures were 29psi front and 36psi rear. What pressure should my 19" tires be?

You should use tires as close as possible to the 986 oe height.

I would see what psi is recommended for late model boxsters with similar size tires.

Compare weight of your car to the boxster you are copying 19" tire sizes from & start with that psi setting. You will want to lower the psi since your car should be lighter than the 981's but it will take time to get it right, better too much psi than too low.