Abstract: This paper comprises of the Design & Fabrication of a Four Wheel Steering mechanism which relatively is a new technology that improves manoeuvrability in trucks, cars, trailers & other four wheelers. In general two wheel steering vehicles, the rear wheels do not play any role in association with the steering, i.e they follow the path of the front wheels. In a four wheel system the rear wheels are made to turn left & right as per the requirements. To keep the operation as simple as possible a computer controlled mechanism can be incorporated for the rear wheels. The rear wheels can be controlled in the following fundamental ways: At slow speeds the rear wheels turn in the opposite direction of the front wheels. This can reduce the turning radius approximately by 21%. At faster speeds on the highway, the rear wheels are made to turn in the same direction of the front wheels. This improves the lane changing manoeuvrability & is particularly beneficial for vehicle towing. Out of the various possible mechanisms, Rack & Pinion type is being presented in this paper.

Keywords: Four Wheel Steer, Quadra-steer, Steering Mechanisms, Turning Radius Reduction.