Premature Front Tire Wear (Set Front Z Height, Toe and Rotate or Replace Front Tires)

This bulletin is being revised to add a build date to the Models. Please discard Corporate Bulletin Number 04-03-07-004A (Section 03 -- Suspension).

Some customers may comment on excessive front tire wear on the inside edge of the tire.

On four wheel drive (4WD) models, an incorrect Z height trim setting, resulting in an excessive front sum toe-out of specification, may be the cause.

On two wheel drive (2WD) models, an incorrect front sum toe setting may be the cause.

Follow the procedure below for diagnosis and repair of this condition.

Important: Prior to performing any tire repairs, permanently record the current tire inflation on the repair order.

1. Permanently record the tire pressure settings on the repair order.
2. Inspect the inside edge of the front tires for excessive wear. Refer to Tire Diagnosis - Irregular or Premature Wear (SI Document ID #408063).

•	If the inner front edge of the tires are worn to the wear indicators, replace the front tires and continue with the next step.

-	For repair information, refer to Tire Mounting and Dismounting (Document ID #290800).

-	For tire warranty information in the U.S., refer to Warranty Administration - GM New Vehicle Tire Warranty Program Bulletin Number 00-03-10-003I, dated June 2005 (SI Document ID #1674498).

-	For tire warranty information in Canada, refer to Warranty Administration - GM of Canada New Vehicle Limited Warranty Tire Program Bulletin Number 01-03-10-003B, dated April 2004 (SI Document ID #1500943).

•	If the inner front edge of the tires are not worn to the wear indicators, rotate the tires and continue with the next step. Refer to Tire Rotation (SI Document ID #291584).

Important: Prior to performing any additional repairs, permanently record the following information on the repair order.

•

Z Height

•	Alignment Measurements

•	Fuel Level

3. Set the inflation per the vehicle tire placard located on the driver's door.

Important: On 2WD models, DO NOT replace the front coil spring(s) or add insulators to compensate for a low trim Z height. A lower trim Z height reading is acceptable as long as it is within specification. Refer to Trim Height Inspection Procedure (SI Document ID #1235409).

4. Check and adjust the vehicle Z height. Refer to Trim Height Inspection Procedure (SI Document ID #1235409).

Important: ON 2WD models, ONLY replace the front coil spring(s) if the trim Z height is too low and out of specification.

5. ON 2WD models, ONLY replace the front coil spring(s) if the trim Z height is too low and out of specification. Refer to Front Coil Springs Replacement (SI Document ID #1217839).
6. Check and adjust the vehicle front toe to 0.00° ± 0.20°. Refer to Front Toe Adjustment (SI Document ID #1208234).
7. Road test the vehicle in order to verify that the steering wheel is straight.

For vehicles repaired under warranty, use: