To improve the cornering performance of a yaw moment control system that assists the self-spinning motion of a competition vehicle, in this paper, we propose a vehicle subjected to electric motor drive torque and brake torque using an actuator. This system is expected to improve the vehicle’s dynamic performance by allowing a rear brake system installed in the right and left tires to be individually actuated. Quasi-static vehicle dynamics analysis of a vehicle equipped with the proposed system was conducted to investigate the improvement of vehicle performance due to active yaw moment changes as a preliminary step to developing control laws for the proposed system. The results of the analysis showed that the maximum steady-state lateral acceleration at a constant vehicle velocity could be improved by 13% by evaluating the cornering performance of the vehicle with and without the system. The required yaw moment change was calculated, and the electric motor torque and actuator force were calculated to satisfy these requirements.