Riding-saddle motor vehicle including a front frame which extends along a longitudinal direction having at least one front wheel, a rear frame having a pair of rear wheels mounted on opposite sides of a rear wheel axis, a motor unit mounted on board the front frame and adapted to provide a driving torque to the pair of rear wheels and/or the front wheel, where the motor unit is connected to the rear wheel axis by means of an articulated transmission joint adapted to allow a relative rotation, around the longitudinal direction, between the front frame and the rear frame, and transmit a driving torque to the pair of rear wheels.