What is Four Wheel Steering?

Four wheel steering is a relatively new technology that improves maneuverability in cars, trucks and trailers. It should not be confused with four wheel drive in which all four wheels of a vehicle are powered.

In standard two wheel steering vehicles, the rear set of wheels are always directed forward therefore and do not play an active role in controlling the steering. In four wheel steering systems, the rear wheels can turn left and right. To keep the driving controls as simple as possible, a computer is used to control the rear wheels.

As shown in the drawing below, most four wheel steering systems can control the rear wheels in the following fundamental ways:

• At slow speeds, the rear wheels are turned in the opposite direction of the front wheels. This can lessen the turning radius by approximately 20%.
• At faster speeds on the highway, the rear wheels are turned in the same direction as the front wheels. This improves lane changing maneuverability and is particularly beneficial for vehicles towing a trailer.

slow speeds

rear wheels are turned
in opposite direction
of front wheels

fast speeds

all four wheels
are turned in
same direction

Four wheel steering is growing in popularity and you are likely to see it in more and more new vehicles. As the systems become more commonplace you can expect the cost of four wheel steering to drop.