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 TiresAdditional links
Instrument Cluster Replacement
Preliminary Procedure
Remove instrument panel lower cluster trim plate. Refer to Instrument
Panel Cluster Lower Trim Plate Replacement.
Remove instrument panel steering column upper trim cover. Refer to
Steering Column Upper Trim Cover Replacement.
...
Installation Procedure
Cut the rocker outer panel in corresponding locations to fit the
remaining original panel. The sectioning joint should be trimmed to
allow a gap of one-and-one-half-times the metal thickness at the sectioning
joint.
Create 50 mm (2 in) backing plates from the unused portion of the
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Vehicle Messages
Messages displayed on the DIC indicate the status of the vehicle or some action
that may be needed to correct a condition. Multiple messages may display one after
the other.
The messages that do not require immediate action can be acknowledged and cleared
by pressing SET/CLR. The messages tha ...