Factors such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions affect the wear rate of the tires.

Treadwear indicators are one way to tell when it is time for new tires.
Treadwear indicators appear when the tires have only 1.6mm (1/16 in) or less of tread remaining.
The rubber in tires ages over time.
This also applies to the spare tire, if the vehicle has one, even if it is never used. Multiple factors including temperatures, loading conditions, and inflation pressure maintenance affect how fast aging takes place. GM recommends that tires, including the spare if equipped, be replaced after six years, regardless of tread wear. The tire manufacturer date is the last four digits of the DOT Tire Identification Number (TIN) which is molded into one side of the tire sidewall. The first two digits represent the week (01–52) and the last two digits, the year. For example, the third week of the year 2010 would have a four-digit DOT date of 0310.
Vehicle Storage
Tires age when stored normally mounted on a parked vehicle. Park a vehicle that will be stored for at least a month in a cool, dry, clean area away from direct sunlight to slow aging. This area should be free of grease, gasoline, or other substances that can deteriorate rubber.
Parking for an extended period can cause flat spots on the tires that may result in vibrations while driving. When storing a vehicle for at least a month, remove the tires or raise the vehicle to reduce the weight from the tires.
Tire Rotation
Buying New TiresAir Conditioning Compressor Replacement (1.6L LDE, LXV, and 1.8L 2H0)
Preliminary Procedures
Recover the refrigerant. Refer to Refrigerant Rec . overy and
Recharging.
Remove drive belt. Refer to Drive Belt Replacement.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
Disconnect the A/C compressor electrical connector
Re ...
Overlap/Backing Plate Sectioning (Welding)
Warning: Refer to Approved Equipment for Collision Repair Warning in
the Preface section.
Fit the service panel to the vehicle to ensure a proper fit.
Measure and mark a line at the sail panel 120 mm (4 3/4 in) from the
back glass opening and 70 mm (2 3/4 in) rearward from the ...
Floor Air Outlet Duct Replacement - Right Side (Right Hand Drive)
Removal Procedure
Remove instrument outer trim cover -- right side. Refer to Instrument
Panel Outer Trim Cover Replacement - Right Side.
Remove instrument panel lower trim pad cover -- left side. Refer to
Instrument Panel Lower Trim Pad Cover Replacement.
Remove flo ...