Abstract: An adaptor assembly for securing a wheel alignment device to a wheel, especially a vehicle wheel. The adaptor of the present invention allows such a device to be secured to a vehicle wheel even if the wheel is substantially flangeless in design. The adaptor assembly includes a collar that releasably engages an adaptor pin portion of a wheel alignment device. The collar allows the adaptor assembly to rotate about an axis defined by the adaptor pin. A wheel contacting means is connected to the collar by a plate member. Once installed to a wheel, an outward movement of wheel alignment device extension arms to which the adaptor pins are attached causes the wheel contacting means to be forced against a wall of the wheel, thereby causing a self-centering of the wheel contacting means and a securing of the wheel alignment device to the wheel.