VEHICLE CARE 293Warning (Continued)can be used; however, use a scraperor wire brush later to remove allrust or dirt.Lightly coat the center of thewheel hub with wheel bearinggrease after a wheel change or tirerotation 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 NewTiresFactors such as maintenance,temperatures, driving speeds, vehicleloading, and road conditions affect thewear rate of the tires.Treadwear indicators are one way totell when it is time for new tires.Treadwear indicators appear when thetires have only 1.6 mm (1/16 in) orless of tread remaining.See Tire Inspection 0 291 and TireRotation 0 291.The rubber in tires ages over time.This also applies to the spare tire,if the vehicle has one, even if it isnever used. Multiple factors includingtemperatures, loading conditions, andinflation pressure maintenance affecthow fast aging takes place. GMrecommends that tires, including thespare if equipped, be replaced after sixyears, regardless of tread wear. Toidentify the age of a tire, use the tiremanufacture date which is the lastfour digits of the DOT TireIdentification Number (TIN) which ismolded into one side of the tiresidewall. The first two digits representthe week (01–52) and the last twodigits, the year. For example, the thirdweek of the year 2010 would have afour-digit DOT date of 0310.Vehicle StorageTires 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 slowaging. This area should be free ofgrease, gasoline, or other substancesthat can deteriorate rubber.Parking for an extended period cancause flat spots on the tires that mayresult in vibrations while driving.When storing a vehicle for at least amonth, remove the tires or raise thevehicle to reduce the weight from thetires.
