What is the difference between tracking and four wheel alignment?
Tracking was invented for when cars had very little or no adjustment. Any measurement and adjustment tended to be on the front wheels, for the ‘Toe’ angle only. Tracking on the fronts (sometimes called a ‘two wheel alignment’) does not take into account the direction in which the rear wheels are pointing. So if you have the fronts adjusted and set straight, if the rears are out of alignment, the car may pull and tyres could still wear. Tracking uses gauges (usually the hang-on style) where the operator peers through a ‘scope’ or views a light/laser beam on a scale. This system does not allow for run out compensation (taking account for any errors in the wheel rim), so the reading result can only at the very best be approximate. Four wheel alignment measures a minimum of 12 angles and compares them to the alignment data specified by the vehicle manufacturer. Wheel rim run-out compensation is taken into account, which gives accurate and repeatable readings. With such accurate readings, four wheel alignment allows toe adjustments of individual wheels which ensure the steering wheel is set straight. Further adjustments of camber, caster and other angles (where necessary) can ensure optimum performance and savings.On modern cars, tracking alone is unlikely to deliver complete alignment or complete customer satisfaction.