Components in both the steering and suspension systems determine the alignment of a vehicle’s wheels. Many of these parts, like track rods and control arms are adjustable to compensate for changes in the suspension and steering systems over time.
The main alignment angles are toe, camber and caster.
Why does wheel alignment matter?
The toe alignment angle determines where the tyres are pointed in relation to each other. It is usually adjusted by the track rods. Vehicles with excessive toe in or toe out can experience rapid tyre wear and may also experience feathering of the tyre tread.
The camber angle is the angle that the tyre makes relative to vertical. Excessive camber in either direction can cause tyre wear on just one edge of the tyre and can create a pulling force that will cause the vehicle to drift as it moves down the road. Camber angles are especially affected by the suspension components. Worn suspension springs and shock absorbers allow the vehicle to sit lower, causing negative camber.
The caster angle is the angle between vertical and the steering pivot axis. Caster can be adjusted by moving the top of the struts forward or rearward. Caster angles that are out of adjustment usually won’t cause tyres to wear, but may cause the vehicle to pull if caster angles differ greatly between the two front wheels. Caster can also affect the steering effort.
An example of toe-in, which can cause extreme tyre wear.
An example of negative camber, which can cause wear and feathering of tyre tread.