Type of wheel balancing.

Tyre and wheel assemblies can be balanced in 2 ways:
statically and dynamically.

Static balance is also called single plane balance. Tyres are statically balanced when they are done on a bubble balancer. When an out-of-balance tyre and wheel are mounted on a freely moving spindle, any heavy spot rotates to the bottom. Weights are added to counter balance the heavy spot. Once the heacy spot has beenbalanced out, the tyre stays at any position it is placed on the spindle.

Dynamic balancing (2 plane balance) reveals whether a tyre/wheel assembly is unbalanced from side to side as well as about its center. Dynamic imbalance can result in vibration and, sometimes, a steering wheel sensation called shimmy.

Most modern tyre service location use off-the-car (off wheel balancing) computer balancing which correct for both static and dynamic imbalance.

NOTES:
1.)Radials tyres should always be dynamically balanced.
2.)Correct dynamic balance are more better result in wheel vibration and steering wheel sensation than static balance.