A wheel mounting assembly for a tire balancing machine of a type for rotating a wheel with a tire mounted thereon includes an annular support plate arranged to be mounted for rotation by the machine. The support plate carries means for simultaneously moving a plurality of studs uniformly between first and second radial positions defined about the axis of rotation of the support plate. The foregoing means includes a central gear disposed on the axis of rotation of the support plate. A plurality of satellite gears corresponding in number to the number of the studs needed for support of a given wheel are disposed about the axis of rotation of the plate in engagement with the central gear. The studs are carried on means supported from each satellite gear so as to revolve about the axis of rotation of the satellite gears whereby rotation of one of the satellite gears serves to rotate the others to the same degree via the central gear so as to move all studs simultaneously from the first to the second position.