Wheel alignment and wheel balancing are not the same but are often mentioned together because a service provider can check both during a requested service. Wheel alignment involves a procedure that adjusts the angles of the wheels so that they are perpendicular to the ground and parallel to each other, that is - the geometric alignment of each wheel in relation to the vehicle’s centre line. Alignment angles often degrade from factory settings through normal wear and tear and/or damage. Where wheel alignment is poor, vehicle control and stability will be compromised, particularly where a vehicle is fitted with an electronic stability control program.
Wheel balancing enables wheels and tyres to spin without causing vibrations and relates to each wheel and tyre assembly rotating smoothly. This is checked using a wheel balancing machine to balance a wheel whenever a new tyre is fitted or during routine vehicle servicing. This balancing procedure involves checking and compensating for any heavy spots on the wheels and tyres.
Different symptoms may arise when a car requires wheel alignment, and when the wheel is unbalanced. Where wheel alignment is required, the tyres will often show uneven wear, the car will pull or drift away from a straight course when driving on an even surface, or it will wander on a straight level road, and the angle of the steering wheel may veer to one side while driving on a straight and level road. Symptoms that indicate that wheel balancing is required include vibration of the steering wheel, seats or floor while travelling at certain speeds, and a scalloped or cupped pattern of wear on the tyres. As poor alignment or unbalanced wheels have a detrimental effect upon the steering, suspension, tyres and safety, it is recommended that both are checked at least yearly.