Tires and wheels alike, inevitably have "heavy spots". In a circumstance where theses heavy spots are more pronounced, the machine will identify the spots that are heaviest. The tire can then be rotated on the rim so that the heavy spots on the rim and on the tire are oriented opposite one another, and the tire can then be more accurately balanced.
If a tire has excessive runout, or is out of round, it can be identified immediately without several attempts to balance a tire before condemning the tire.
Most people that will opt for a roadforce balance will do so for diagnostic purposes because no matter how many balance attempts are made, there is still a shake, vibration or tire pull.
A roadforce machine also will print detailed diagrams relating to balance and location of the tire that can be useful in obtaining compensation for defective tires.