wheel alignment

Tracking was born of a bygone era, 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 in 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.

In its original sense, 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 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.

TOE

Toe is the angle of the wheels in relation to the vehicles centreline (an imaginary line straight down the centre of the vehicle, when viewed from above).

Just as the name suggests, imagine the pair of wheels (front or back wheels) as a pair of feet.

When you turn your toes inwards and your heals out, this is what is know as Toe-in . And yes, you’ve guessed it; when you turn your toes out and heels in, this is Toe-out.

When this happens to wheels, you end up wearing the edges of your tyres excessively:

Toe in or Positive Toe causes your car to wear the outside edges

Toe out or Negative Toe your car will wear the inside edges

INDIVIDUAL TOE

Individual toe is measured from the vehicle centre line. Individual toe can be thought of as a 'per wheel' value.

TOTAL TOE

Total Toe is the sum of two individual toe angle readings added together.

CAMBER

Think of Camber as the amount of ‘tilt’ of the wheel, one way or the other.

Positive Camber is when the top of the wheel leans away from the car

Negative Camber is when the wheel leans in at the top

The amount of tilt doesn’t have to be much and not always noticeable to the eye, but it is enough to cause undue tyre wear and make the car pull

CASTER

The easiest way to understand Caster is to look at a bike (when viewed sideways on). If you draw a line down from the centre point on the handlebars down the forks to the ground (on a car this would be the suspension strut), this indicates the 'pivot point'.

Then draw a second line vertical through the centre of the wheel and where this touches the ground shows the 'tyre contact point'.

The top angle that has been created is what is known as the Caster Angle.

If this top angle is reduced then stability is less, therefore it is important to get the Caster set to its optimum angle for the best possible control.

CENTRE LINE

Is literally just that! An imaginary line running down the centre of the car, from the front to the rear and equidistant from the sides.

THRUST ANGLE

Thrust angle is the direction the rear wheels are pointing in relation to the centre line. If the thrust angle is not zero the vehicle will ‘crab’ – move sideways from the back!

STEER AHEAD

This is simply to ensure the steering wheel is set straight when the vehicle is travelling along a straight and flat road