A tool for mounting a motor-vehicle wheel on a wheel hub includes a tubular body having a coupling portion arranged for coupling to the wheel hub, and a carrier portion for supporting the motor-vehicle wheel during a centering phase of the wheel on the hub. The tool has an inner tubular member and an outer tubular member rigidly connected to each other so as to be coaxial. At the coupling portion, the inner and outer tubular members are spaced apart so as to define a space arranged to receive an end portion of the wheel hub, in such a way that, in an operating condition, the end portion of the hub is interposed between the inner tubular member and the outer tubular member.