GM Service Manual Online
For 1990-2009 cars only

Lead is the deviation of the vehicle from a straight path on a level road, without hand pressure on the steering wheel. Lead is usually the result of one of the following conditions:

  1. Tire construction. Refer to Diagnostic Information and Procedures in General Information
  2. Uneven parking brake adjustment. Check parking brake adjustment
  3. Wheel Alignment

The way in which a tire is built may produce lead. Rear tires do not cause lead.