Toe-in is the adjustment of the front wheels that angles the tires toward each other. The actual amount of toe-in is normally a fraction of a degree. The toe-in is measured from the center (2) of the tire treads or from the inboard side of the tires. The purpose of the toe-in is to ensure parallel rolling of the front wheels and in order to offset any small deflections of the wheel support system which occurs when the vehicle is rolling forward. The incorrect toe-in results in excessive tire wear and unstable steering. The toe-in is the last alignment to be set in the front wheel alignment procedure.

The caster, the camber, and the toe-in are the dimensions determined for the vehicle at the design load with the frame level. The normal frame angle must be considered when using the alignment equipment. This is most important when making a caster angle check in order to obtain a true setting.