Abstract: A wheel balancer having a threaded shaft with a free end for receiving a wheel to be balanced and a drive for rotating the shaft to a wheel secured thereon so as to enable the obtaining of data relative to imbalance of the wheel as the wheel rotates. A locating device is provided for engaging a wheel on the shaft to locate the wheel properly thereon and a nut is utilized in connection with the shaft for holding the wheel against the locating device. The nut includes apparatus for selectively moving the nut threads radially inwardly into engagement with the shaft threads and radially outwardly out of engagement with the shaft threads so that the nut may be rapidly advanced on or removed from the shaft without rotation when the nut threads are out of engagement with the shaft threads.