When should you check the pressure in tires of a passenger car?

You check the tyre pressure directly before the start of a journey, when the tyres are cold - answer A. After driving (B) the rubber is warm and the air inside has expanded, so the pressure gauge will show a value that is more than ten percent higher, and you may wrongly let air out. A measurement a day earlier (C) does not guarantee that the pressure will be correct on the day you leave - a tyre loses air slowly, and a change in temperature also changes the pressure.

The manufacturer gives the pressure values for cold tyres, usually on a sticker in the driver's door or on the fuel filler flap. Pressure that is too low increases the braking distance, makes handling on bends worse, increases fuel consumption and may cause the tyre to overheat on a motorway. Before a longer trip, especially with luggage, you check the pressure and, if necessary, raise it to the value for a full load.