Air pressure in tires, including the spare, should be checked at least monthly and always before extended driving. Tires should be checked when they are cold (at least three hours after the vehicle has been stopped and before it is driven more than one mile or two kilometers). Do not reduce pressure when tires are hot; use an accurate air pressure gauge to check pressure and maintain it at the level recommended on the vehicle tire vehicle placard or in the vehicle owner’s manual. Under-inflation produces extreme flexing of the tire and builds up heat to the point that tire failure may occur. Over- or under-inflation may adversely affect vehicle handling. Cold tire pressures should never be higher than the limit molded on the sidewall.