VEHICLE CARE 291Warning (Continued)can be used; however, use a scraperor wire brush later to remove allrust or dirt.Lightly coat the centre of thewheel hub with wheel bearinggrease after a wheel change or tyrerotation to prevent corrosion orrust build-up. Do not get greaseon the flat wheel mountingsurface or on the wheel nuts orbolts.When It Is Time for NewTyresFactors such as maintenance,temperatures, driving speeds, vehicleloading, and road conditions affect thewear rate of the tyres.Tread wear indicators are one way totell when it is time for new tyres.Tread wear indicators appear whenthe tyres have only 1.6 mm (1/16 in)or less of tread remaining. See TyreInspection 0 289and Tyre Rotation 0 289.The rubber in tyres ages over time.This also applies to the spare tyre,if the vehicle has one, even if it isnever used. Multiple factors includingtemperatures, loading conditions, andinflation pressure maintenance affecthow fast ageing takes place. GMrecommends that tyres, including thespare if equipped, be replaced after sixyears, regardless of tread wear. Thetyre manufacture date is the last fourdigits of the DOT Tyre IdentificationNumber (TIN) which is moulded intoone side of the tyre sidewall. The firsttwo digits represent the week (01–52)and the last two digits, the year. Forexample, the third week of the year2010 would have a four-digit DOTdate of 0310.Vehicle StorageTyres age when stored normallymounted on a parked vehicle. Park avehicle that will be stored for at leasta month in a cool, dry, clean areaaway from direct sunlight to slowageing. This area should be free ofgrease, petrol, or other substancesthat can deteriorate rubber.Parking for an extended period cancause flat spots on the tyres that mayresult in vibrations while driving.When storing a vehicle for at least amonth, remove the tyres or raise thevehicle to reduce the weight from thetyres.
