Characteristically fully hydraulic steering systems do not rely on a mechanical link between the steering wheel and the wheels on the ground. This is a major advantage for the vehicle designer and is probably one of the main drivers for the widespread success of fully hydraulic steering systems. However, the absence of a mechanical link leads to a loss of positional relationship between the steering wheel and the wheels on the ground. The relationship between the rotational position of the steering wheel and the driving direction of the vehicle may vary. This is a traditional short coming of fully hydraulic steering systems, and is well understood in the industry. OSPM is available in open center non-reaction, power beyond non-reaction and LS dynamic non-reactions versions.