Is 4-Wheel Steering Really Worth the Hype in Racing Cars?

[talanum1]

Won't a racing car handle better if the back wheels could also steer like the front ones (especially during controlled skids around corners)?

It would need to be controlled by computer with settings for tarred or dirt roads.

 

[timmay]

It doesn't necessarily need to be actively controlled (look at the Honda Prelude), and can help with stability (and probably tire wear) but usually incurs a weight penalty and added complexity.

 

[Codyt]

There would be more weight added, which would hurt performance, and the added weight in the rear of the car would throw of the balance of the car which would hurt handling. Also, the computers to control the rear steering would have to be extremely quick in order to calculate understeer, oversteer, tire wear, track temperature and other variable.

Why would any race car driver want to take a skid around a corner, even a controlled one, when it is much better to hit the apex of the turn.

 

[PaulS1950]

Codyt,
Tires have slip angles - on a track the tires always slip around a corner.
That being said there are conditions that cars must slide (grossly) around corners. Dirt ovals are one situation where the cars need to slide through corners o maintain their speed.
The concept of "handling better" is subjective to the driver. Some drivers like a car to be "loose" on the exit of a corner and others like a car that "pushes" on exiting the corner. A drivers "style" determines to a great degree how the car is set up to handle.
It is always easier to adjust a car to the driver than it is to adjust the driver to the car.
since the main racing organizations have not tried to use the technology of rear wheel steering it would seem that it is either already addressed as illegal or not seen as applicable to the racing situations.

 

[Wetmelon]

I BELIEVE that in Formula SAE, you are allowed to use active rear steering up to 15% of the front steering. Of course this is highly complicated and I don't know of any teams that actually use it. Perhaps you can ask on the SAE forums:

http://fsae.com/groupee?s=763607348&cdra=Y

 

[jack action]

Actually, it can be proven mathematically that 4-wheel steering doesn't give a real advantage, performance wise. It gives the impression of performance, as it is possible to always maintain the vehicle correctly aligned with its path. But, simply put, the coefficient of friction of the tires remains the same, so the car won't stick more to the ground (http://www.auto-ware.com/setup/fc1.htm").

The real advantage for the 4-wheel steer is the smaller turning radius at low speed, which is helpful in parking maneuvers (especially for http://www.usatoday.com/money/autos/reviews/healey/2003-02-13-qsteer_x.htm").

You don't need high-tech computer to built a 4-wheel steering, even though the wheels have to change direction depending if the vehicle is at low or high speed. The reason for the different rear steering angle depending on speed is, as I mentioned earlier, to keep the vehicle longitudinal axis parallel with the path it follows (again, big math proof, but too large for this post). (http://www.wisegeek.com/what-is-four-wheel-steering.htm")