it should say somewhere in your door. they give you optimal inflation for the tire size for gas mileage. it will say in your manual too.
__________________
Driving the S4 is like having a big d*ck; it's not immediately obvious to everyone, but you have to just rest assured that when it comes time to put it to use, you won't need to explain a whole lot afterwards... haha
Door? Over here it's on the gasflap. You know the little flap you open to fill the gastank. Usually it's between 2.5 and 3 bar but it also changes per tire brand. You can ask your tire supplier or your dealer what the optimum pressure is with a certain brand of tire and your car.
__________________ One is not superior merely because one sees the world as odious.
Tire Pressure 
Linear Mode
