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 TiresTest Probe Caution
Caution: Do not insert test equipment probes (DMM etc.) into any
connector or fuse block terminal. The diameter of the test probes will
deform most terminals. A deformed terminal will cause a poor connection, which
will result in a system failure. Always use the EL-35616
GM-Approved Terminal T ...
Danger, Warnings, and Cautions
Warning messages found on vehicle labels and in this manual describe hazards
and what to do to avoid or reduce them.
Danger indicates a hazard with a high level of risk which will result in serious
injury or death.
Warning or Caution indicates a hazard that could result in injury or death.
WA ...
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 ...