A computer system and computer-implemented method for determining a rotational speed limit for a steered axle of a vehicle having two steered axles are disclosed. The computer system has processing circuitry to acquire a combined slip limit for the steered axle based on a slip diamond; determine a longitudinal slip limit for the steered axle based on the combined slip limit and a current lateral slip of the steered axle; and determine a rotational speed limit for the steered axle based on the determined longitudinal slip limit, a radius of a wheel of the steered axle, and a current longitudinal velocity of the vehicle.

A hybrid-drive motorcycle comprising an endothermic engine, a rear wheel connected to a carrier structure through a swingarm, a gearbox connected to the endothermic engine through a primary transmission and to the rear wheel through a secondary transmission, and a reversible electric machine, wherein an auxiliary transmission connects the electric machine to an input shaft of the secondary transmission, and wherein the electric machine is mounted on the carrier structure below the swingarm.