Tire balance refers to the distribution of mass within an automobile tire or the entire wheel to which it is attached.
When an improperly balanced or unbalanced wheel rotates, asymmetries of mass may cause it to hop or wobble, which can cause ride disturbances (usually vertical and lateral vibrations). It can also result in a wobbling of the steering wheel or of the entire vehicle. Ride disturbance, caused by unbalance, usually increases with speed. Vehicle suspensions can become excited by unbalance forces when the speed of the wheel reaches a point that its rotating frequency equals the suspension's resonant frequency.
When tires are fitted to wheels at the point-of-sale, they are generally placed on a balancing machine, and correction weights are applied to counteract the combined effect of the tire and wheel unbalance.