Tracking & Wheel Alignment
Wheel Alignment or Tracking as it is also known as, effects the way the vehicle handles, corners and importantly the wear on the tyres.
In more modern vehicles, it can also cause a fault with the steering angle sensor ( a sensor sat behind the steering wheel that measures the angle of the front wheels through the angle of the steering wheel).
All production cars are factory-specified with a little bit of front wheel toe-in - that means that the forward faces of the tyres are slightly (about 1/8th of an inch in most cases) closer together than the rear faces.
Similarly, most production car rear wheels are designed with some amount of toe-in. The practical effect of this setting is that your wheels are always driving a little bit towards the centre of the car.
This gives your car a nice stable feeling on the road, but it also means you have increased the rolling resistance of your tyres. Toe-in also means you have to turn the steering wheel farther to get both front tyres pointed into a turn, and the inside tyre won't ever be pointed as far into the turn as the outside tyre.
2 Wheel Alignment
2 Wheel Alignment (tracking) is essentially aligning the front wheels of the car to point straight, so that the car will drive in a proper straight line.
Most vehicle do not have adjustable rear suspension, so this is the only type of adjustment that can be done
4 Wheel Alignment
4 Wheel Alignment applies to vehicles with adjustable rear suspension. First the rear suspension is adjusted to run straight with the front of the car, then the front adjusted to match the rears.
To find out more on how poor alignment damages tyres and handling click below.