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 TiresRear Bumper Impact Bar Replacement
Preliminary Procedure
Remove the rear bumper fascia. Refer to Rear Bumper Fascia Replacement.
Rear Bumper Energy Absorber Nut (Qty: 6)
Caution: Refer to Fastener Caution in the Preface section.
Tighten
40 N·m (30 lb ft)
Rear Bumper Impact Bar
Special Tools and Equipment
...
Door Locks
WARNING
Unlocked doors can be dangerous.
• Passengers, especially children, can easily open the doors and fall out of
a moving vehicle. The chance of being thrown out of the vehicle in a crash is increased
if the doors are not locked. So, all passengers should wear safety belts properly
and ...
Shock Absorber Disposal
Warning: Gas charged shock absorbers contain high pressure gas. Do
not remove the snap ring from inside the top of the tube. If the snap
ring is removed, the contents of the shock absorber will come out with extreme
force which may result in personal injury.
Warning: To prevent personal inju ...