It might be a bit of a dumb question, but when you're checking tire pressure, is the proper way to check it when the car is resting on the tire, or when the wheel is off the car, or the car is lifted in the air?

It would seem that if the car is resting on the tire, its compressing it, and the pressure inside the tire increases? So in fact if you were to pump your tires to 32psi when the car is on the lift, and then lower the car, the tire pressure will increase?

 

it will read the same

 

It will be the same no matter what.