When making a turn in an ordinary car without 4-wheel steering, there's a delay between the rotation of the steering wheel, and the moment the car actually starts to turn. The cause of this is, while the front wheels are building up side-thrust, chassis movement has to take place first, then finally getting the rear wheels to follow along. In order to improve cornering, Honda developed a system for the Prelude in which the rear wheels steer along.

On the 4-wheel steering Preludes, every steering movement is transfered directly to all four wheels. The rotation of the steering wheel sets the steering angle for the rear wheels. At high speeds this translates into high stability, while at low speeds it offers great agility.

The system Honda uses is technically simple. It steers the four wheels completely mechanically. The 4-wheel steering system consists of a steering rack between the front wheels, a connecting shaft, and a second steering rack between the rear wheels. Every movement of the front steering axle is transferred to the rear steering rack by the connecting shaft. How the rear wheels react to that movement is controlled inside the rear steering rack.

When the steering wheel is turned just slightly, as it is when changing lanes or taking long fast corners, the rear wheels steer in the same direction as the front wheels. Thanks to this the Prelude becomes more stable and requires less steering corrections.

The rear wheels now steer in the same direction as the front wheels, making it possible to change lanes over a more flowing line. The steering angle of the rear wheels is much less than the angle of the front wheels. The optimal steering ratio between the front and rear wheels has been determined by Honda through computer simulations and test driving.

At low speeds and more steering wheel rotation, the rear wheels steer in the opposite direction of the front wheels. The steering becomes more direct because for making the same turn, the steering wheel has to be turned less. The rear wheels follow the track of the front wheels, making it seem like the Prelude is actually on a railtrack while turning. Because sharper turns are possible, parking is also much easier. It's now possible to park the Prelude into a space just barely longer than the car itself.

Compared to the Prelude without 4-wheel steering, the minimal turning cycle of the 4-wheel steered Prelude is a firm one meter shorter. Therefor the car can make considerabely shorter turns. If you first drive with 4-wheel steering, it takes some getting used to. You can really cut off corners, so watch out for curbs if you don't want to damage your rims.

This is the rear steering rack on my Prelude. Here it's dirty and rusty, but that'll change. The subframe onto which the steering rack is mounted is going to be sandblasted and powdercoated black. And of course the rest has to be cleaned.

The secret of 4-wheel steering is inside the rear steering rack, pictured here. You can see a big gear, called a planetary gear. It's surrounded by a gear ring which in turn is connected to the steering axle by a double eccentric transfer. This double transfer makes the steering axle move into the same direction as the front wheels when there's little rotation, and move opposite when there's more.

The front steering rack of a 4-wheel steered system of course differs from the steering rack of a 2-wheel steered one. There's an extra coupling where the connecting shaft is attached to. On the photo beside, you see the coupling sitting on top of the steering rack.

Because my steering rack was quite dirty and off the car anyway, I took the occasion to clean it while I could still reach it this easily. As you can see, some cloth with degreaser works miracles. I put new grease into the steering axle covers as well. After placing back the cleaned hoses, this steering rack is ready for refitment to the Prelude.

The difference between the front steering racks. The upper rack is from an EX while the lower rack comes from the 16-valve version equipped with 4-wheel steering. The diameter of the front 4-wheel steering rack is larger because of the extra coupling for the connecting shaft. The frames where both steering racks are mounted in, are equal.

Cleaned steering rack and coated subframe.