Abstract: A device for balancing a wheel mounted on a vehicle wherein the device is put in contact with the wheel by means of an adaptor cap which replaces the dust cap on the end of the wheel spindle. The wheel is driven at a high rate of speed with a probe centered relative to the end of said wheel spindle. When the heavy portion of the out-of-balance wheel moves up past true center, the probe actuates an electric switch by means of a rotor shaft, axially aligned with said probe, to complete an electric circuit to at least one indicator light of a first set of lights by means of a brush contact, fixed to the rotor shaft, for sequential engagement with a plurality of annularly disposed rotor plates. The last light to be illuminated of said first set indicates the exact location of the heavy portion.