Wheel Alignment Basics and Benefits
Even if you have a million horsepower coming from the engine, but you cannot properly transfer it to the road, it’s not of much help. To do this, you will need proper wheels and they must be connected to the car properly. Wheel alignment tries to ensure that all four wheels, or any other number where applicable, are parallel to each other, the road and their respective axles. Properly aligned cars produce the most amount of traction, the least tyre wear and least rolling resistance. But to do this, however, three alignment angles must be adjusted.
This refers to how parallel the wheels are as viewed from above. Ideally, both front wheels should be aimed straight ahead with the distance between the leading edges exactly the same as the distance between the trailing edges. However, the rubber bushings, steering linkages and joints in the suspension all have a little natural play. To compensate a fraction of an inch of toe-in or toe-out may be added while aligning the wheels. Toe-in means the leading edges of the tyres are closer together than the rear edges. Toe-out is when the front edges are further apart than the rear edges, and is a sign of worn tie rod ends. This causes the tires to scrub and wear away easily.
Camber is when the tyres are perfectly perpendicular to the road when viewed from the front or rear. If the tyres tend to tilt inward, the car is said to have negative camber, and if they tilt outward, it’s said to have positive camber. Zero camber would be the ideal setting, but as with toe, the suspension bits and load affect camber to some degree. Depending on the design of the suspension, one may allow a degree or more of negative or positive camber to balance out when driving. If camber is misaligned, a tie wears unevenly on one shoulder and usually affects only one wheel.
This refers to the forward to rearward tilt of the steering axis, as viewed from the side. It only applies to the front wheel, as they are the ones used for steering. Although it doesn’t affect Tyre wear directly, a car with caster-off has a noticeable effect on steering stability, effort and steering return. Most vehicles have a bit of positive caster, which improves steering and high-speed stability. This helps to keep the wheels aimed straight and to return to the straight-ahead position after turning.