An out of balance wheel or wheels will cause a vehicle to vibrate either trough the steering wheel or the seats of the vehicle. This vibration generally occurs at higher speeds of between 80 -110km/hour. This vibration is due to a heavy spot in the wheel.
Each wheel is removed from the vehicle and mounted, one at a time, onto a balancing machine where it is measured and spun to locate the heavy spot. A counter weight is then attached to the wheel opposite to this spot and as a result the wheel will spin true resulting in a smooth comfortable drive.
As a general rule a high quality tyre will require less weight when being balanced, as it is made to a higher quality and standard, as well holding their balance for a longer period of time.