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Wheel Alignment

Common Suspension Terminology - and what to look for...


CAMBER ANGLE

Camber is the measurement of the inclination of the wheel from the vertical, viewed from the front of the vehicle. Camber’s main purpose is to reduce uneven tyre wear on the edges of the tyres by maintaining even contact across the entire tread surface. The vehicle has “+” positive camber when the top of the tyre leans outwards away from the vehicle and has “-” negative camber when the top of the tyre leans inwards towards the vehicle. Under normal driving conditions original rubber bushings or worn components distort and squirm causing the suspension arm to move altering camber setting, resulting in unwanted angle changes. Nolathane suspension products are far superior in maintaining proper camber settings because they do not distort as much as the original rubber components.

What to look for: Smooth edging on the inside of the tyre is caused by excessive “-” camber, smooth edging on the outside of the tyre is caused by excessive “+” camber causing the vehicle to pull to the side with the most “+” camber. Always wheel align camber settings within manufacturer’s specifications.


CASTER ANGLE

Caster is the measurement of the angle of forward and backward tilt of the upper and lower steering pivots (i.e. top and bottom ball joints) relative to an imaginary vertical line intersecting the road surface, also measured in “+” positive and “-” negative degrees. Caster is the angle that most effects directional stability. “+” caster occurs when the contact patch of the tyres is behind this imaginary line, “-” caster being in front of the line. Ideally the contact patch of the tyres would be “+” providing steering ‘feel’, stability and helping to self centre the wheels, so they point in the direction the vehicle is travelling. Too much caster causes heavy steering and when extreme, can cause wheel shimmy. Too little caster reduces steering feel and the vehicle’s ability to track straight and has a tendency to wander. Under heavy braking and steering conditions, original rubber or worn components can cause caster angle change effecting the vehicle’s self-centring ability and reducing turn-in ability when cornering. Nolathane suspension products provide better control under all conditions, especially braking, controlling and preventing movement. Negative effects caused by the camber of the road can be counteracted by increasing the caster of the vehicle on the passenger side by approximately 1/2o. This spread is provided by Nolathane’s range of offset caster bushings reducing LH tyre wear, rectifying a slight pull to the LHS, common in many front wheel drive vehicles.

What to look for: Unless there is excessive “+” caster on cars not designed to have such settings, caster will not normally cause tyre wear. Always wheel align caster settings within manufacturer’s specifications.


TOE IN / TOE OUT

Toe is the measurement of the difference between the front centre line of each tyre and the rear centre line of each tyre on the same axle. Incorrect toe settings are one of the main causes of excessive tyre wear, notably feathered edging across the tyres, is due to incorrect toe settings due to the tyres trying to run in different directions. Vague, unresponsive steering is indicative of excessive toe in, whereas excessive toe out causes the vehicle to dart or wander across the road. Toe angle is measured in “degrees” or “mm” by subtracting the distance between the front of the tyres from the distance between the back of the same tyre. A”+” result means the vehicle is toeing in, a “-” result means the vehicle is toeing out. Typically production vehicles are normally aligned with a “Toe In” setting as steering alignment takes place while the vehicle is stationary. When the vehicle is in motion steering linkage tolerances allow the wheels to move out under normal driving conditions. This is referred to as “Running Toe” which should be zero to maximise tyre life and achieve the least rolling resistance.

Toe settings can be altered because of soft original rubber bushings or worn components allow the control arms to move during performance driving, heavy braking and cornering causing toe out. Nolathane suspension products are far superior in maintaining proper toe settings under performance situations, when weight transfer is high, such as acceleration, braking and cornering as they do not distort like the original rubber components.

What to look for: Feathered edges on the tyres indicates incorrect toe setting. Feathering pointing to the inside of the tyre indicates excessive toe in, whereas feathering to the outside of the tyre indicates excessive toe out. Always wheel align toe settings within manufacturer’s specifications.


SWAY BAR CONTROL

The function of the sway bar is to improve the tyre contact with the road, thus reducing body roll and stabilising the vehicle under lateral (cornering) loads. Soft original rubber bushings will often deflect excessively before the sway bar begins to operate, therefore permitting initial body roll.

Nolathane suspension products allow the sway bar to work with much higher efficiency as the bushings do not distort, resulting in improved performance, control, less tyre wear and better traction.

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