To Celsius: The pressure given by the car manufacturers is the MIN. pressure. Not the optimum. No harm to put 0.5 bar extra into. Check the info's provided by the car manufacturers, there are also different pressures given for "empty" cars and fully loaded cars. The AA says as well that putting an extra 0.5 bar into the tires is no harm, it benefits the tires because they last longer. The softer they are the more they are kneaded, making the rubber soft/weak and hot due to incresaed movement and therefore increase abrasion. Think logically.Try a hard eraser versus a soft erasor (blue/red).
You aren't selling tires ,are you? (smiley)