Tire Lead

"Lead" is the movement or wander of the vehicle from a straight path on a level road with no pressure on the steering wheel.
Lead is usually caused by:
- Incorrect wheel alignment.
- Uneven or incorrect tire inflation pressures.
- Damaged or worn tire construction.

The way in which a tire is constructed can produce lead. An example of this is placement of the radial belts. Off-center belts on a radial tire can cause the tire to develop a side force while rolling straight down the road. If one side of the tire is a little larger in diameter than the other, the tire will tend to roll to one side. This will develop a side force which can produce lead.

Switching directional tires front to rear or side to side may be done when attempting to diagnose a tire lead, pull or drift condition. After the test procedure, the tires must be returned to their original position.