Slight Pull Left or Right Tire Wander - keywords air alignment brake pressure ride steering suspension

This PI was superseded to update model years. Please discard PIC3144.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers may comment of the vehicle having a tendency to pull left or right depending on road conditions.

On Pontiac Firebird WS6 package, Chevrolet Camaro SS package or Corvette specialty or "upfit" vehicles with oversized (wider) tires, the concern may be even more pronounced. Any vehicle with low aspect ratio tires (ratio between tire height and width as measured from wheel rim to tread and from sidewall to sidewall) is susceptible to this troughing (wide tire wander) condition. The tread foot print tracks in the center of the tire path in the road (especially on black top). Turning the steering wheel left or right slightly may give a "scuffing" feel like rubbing up against a curb (only not as pronounced). The tires have a tendency to follow the trough in the road which provides steering wheel feedback to the driver.

It is possible that this is a NORMAL CONDITION. Ride with the customer in a comparably equipped vehicle over the same roads to diagnose if a problem exists. If a problem is found, check the following areas:

TIRE PRESSURE

Tire pressure has a definite effect on handling, in addition to wear & fuel economy. Over inflation reduces the contact area & worsens the "wander" condition. An over inflated tire rides more on the "ball" of the tire while the edges are curved and provide more input from the road.

Under inflation gives a smoother ride, but handling & tread life are sacrificed. The sidewalls & tread will buckle, reducing the area of the road contact patch and causing a loss of traction, especially on curves. A similar concern can be felt but may have more of a "squirming" or "wiggling" feel.

It is also important that all tires are at the same psi, especially the front. A 1-2 psi difference can be felt. The proper inflation is listed on the tire inflation label attached to the driver's door. TSB 00-00-90-002 contains tire inflation information for all 2001 vehicles.

ALIGNMENT:

Suspension alignment, especially toe settings, should be verified.

WEAR:

Excessively worn tires (out of alignment, age, etc) can also exaggerate the "wander" concern. Swapping tires from a known good vehicle can be an effective diagnostic step to perform.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.