In this paper, a novel flux weakening method is reported for in-wheel motor drives of electric vehicles. The tested in-wheel motors have the features which are interior permanent magnetic synchronous motors (IPMSM), direct drives and outer rotors. Flux weakening methods have been proposed for preventing the saturation voltage of an inverter. First, the differences between the proposed method and the conventional method are explained. Secondly, the accuracy and the robustness of the method are studied. The simulation and experimental results which include test runs by a demonstration electric vehicle show that the proposed system drives the motor precisely.