246 Vehicle careTyres age, even if they are not used.We recommend tyre replacementevery 6 years.Changing tyre and wheelsizeIf tyres of a different size than thosefitted at the factory are used, it may benecessary to reprogramme thespeedometer as well as the nominaltyre pressure and make other vehiclemodifications.After converting to a different tyresize, have the label with tyrepressures replaced.9 WarningUse of unsuitable tyres or wheelsmay lead to accidents and willinvalidate the vehicle typeapproval.Wheel coversWheel covers and tyres that arefactory approved for the respectivevehicle and comply with all of therelevant wheel and tyre combinationrequirements must be used.If the wheel covers and tyres used arenot factory approved, the tyres mustnot have a rim protection ridge.Wheel covers must not impair brakecooling.9 WarningUse of unsuitable tyres or wheelcovers could lead to suddenpressure loss and therebyaccidents.Tyre chainsTyre chains are only permitted on thefront wheels.Always use fine mesh chains that addno more than 10 mm to the tyre treadand the inboard sides (including chainlock).9 WarningDamage may lead to tyre blowout.Tyre chains are only permitted ontyres of size 215/60 R 16 and225/50 R 17.