Most passenger cars will recommend 32 psi to 35 psi in the tires when they're cold. ... For the most accurate reading (not to mention the most consistent one), make sure the car has been sitting overnight or at least has been parked for a few hours. Do not inflate your tires to the pressure listed on the tire itself.

Does tire pressure have to be exact?

Perhaps the most important point in all of this is to find and use the correct tire pressure for your vehicle and that is not the number on the side of the tire! Most vehicles have an optimum tire pressure of 33-36 psi, but the specific pressure for your vehicle can be found in the car's owner's manual.

Should all 4 tires be the same PSI?

Often, the vehicle manufacturers specify more air pressure in the back for this very reason. (Sometimes, not often, they specify a couple of pounds lower in the rear, but rarely more than 2 psi.) ... A good rule of thumb would be to keep the same variance front to rear that the vehicle manufacturer recommends.