The toe is a measurement of how much the front or the rear of the wheels are turned in or out from a straight-ahead position. When the wheels are turned in, toe is positive, and when they are turned out, it is negative. The actual amount of toe is normally only a fraction of a degree.

The toe functions in order to ensure that the wheels roll parallel. It also serves to offset the small deflections of the wheel support system that occur when the vehicle is rolling forward. Even though the wheels are set to toe-in slightly when the vehicle is standing still, with the proper toe the wheels will tend to roll parallel on the road when the vehicle is moving.

An incorrect toe condition will cause an abnormal tire wear and a decreased fuel economy.