General Alignment Information
The main focus for correct wheel alignment is to ensure that everything is running as straight as possible with regard to the road. This minimises tyre wear, fuel consumption and your operating costs. There are 4 main measurements to consider:
Toe - This is the wheel position when viewed from above. In at the front is toe in and in at the back is toe out.
Camber - This is the wheel position when viewed from behind. In at the top is negative camber and out at the top is positive camber.
Castor - This is the contact position of the tyre on the ground relative to the steering axis. If the steering axis is ahead of the ground contact patch, castor is positive. If behind the steering axis, castor is negative.
Thrust Angle / Out of Square - with regard to solid (drive/lazy/trailer) axles, this is the direction an axle is pointing relative to the chassis centre line. An out of square axle will cause crabbing of a vehicle.