GM Service Manual Online
For 1990-2009 cars only

Caution: Do not mix different types of tires on the same vehicle such as radial, bias, and bias-belted tires except in emergencies because vehicle handling may be seriously affected and may result in loss of control and possible serious injury.

This vehicle is equipped with speed rated tires. Listed below are the common speed rating symbols and the corresponding maximum speeds:

Speed Symbol

Maximum Speed (km/h)

Maximum Speed (mp/h)

S

180

112

T

190

118

U

200

124

H

210

130

V

240

149

Z

Over 240

Over 149

A Tire Performance Criteria (TPC) specification number is molded in the sidewall near the tire size of all original equipment tires. Usually, a specific TPC number is assigned to each tire size. The TPC specification number assures that the tire meets the following GM's performance standards.

    • Meets the standards for traction.
    • Meets the standards for endurance.
    • Meets the standards for dimension.
    • Meets the standards for noise.
    • Meets the standards for handling.
    • Meets the standards for rolling resistance, and others.

The following is required of replacement tires:

    • Replacement tires must be of the same size as the original tires.
    • Replacement tires must be of the same speed rating as the original tires.
    • Replacement tires must be of the same load index as the original tires.
    • Replacement tires must be of the same construction as the original tires.
    • Replacement tires must have the same TPC specification number as the original tires.

The following may seriously be affected by the use of any other tire size, tire speed rating or tire type:

    • May seriously affect the ride.
    • May seriously affect the handling.
    • May seriously affect the speedometer/odometer calibration.
    • May seriously affect the antilock brake system.
    • May seriously affect the vehicle ground clearance.
    • May seriously affect the trailering capacity.
    • May seriously affect the tire clearance to the body.
    • May seriously affect the tire clearance to the chassis.

Conditions for Tire Replacement

Replace the tires when one and/or all of the following conditions are evident:

    • When the tire(s) is worn to a point where 1.6 mm (2/32 in) or less of tread remains. The tires have built in tread wear indicators that appear between the tread grooves when the tread is worn to 1.6 mm (2/32 in) or less to help in the detection of this condition. Replace the tire when the indicators appear in two or more adjacent grooves at three spots around the tire.
    • When the following conditions are evident on the tread:
       - When the tread is cracked.
       - When the tread is cut.
       - When the tread is snagged deeply enough to expose the cord.
       - When the tread is snagged deeply enough to expose the fabric.
       - When the sidewall is snagged deeply enough to expose the cord.
       - When the sidewall is snagged deeply enough to expose the fabric.
    • When the following conditions are evident on the tire:
       - When the tire has a bump.
       - When the tire has a bulge (protrusion).
       - When the tire is split.
       - Please note that slight sidewall indentations are normal in radial tires.
    • When the following damage is evident on the tire and the damage cannot be correctly repaired because of the size or the location of the damage:
       - When the tire has a puncture.
       - When the tire is cut, or other damage.

Always install new tires in pairs on the same axle. In the event that only one tire is replaced, then pair with the tire having the most tread.