"Wheel Weight also referred to as tire balance, describes the distribution of mass within an automobile tire or the entire wheel (including the rim) to which it is attached.
When the 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. 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."