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behind the axle steering
Nitrogeno25 - 15/7/13 at 02:02 AM

Is there any benefits of running the steering in front of the axle like all locost style cars? I understand bush deflection in the suspension arms can cause more steering when the steering is behind de axle and less when it's in front.

I also understand ackermann steering is easier to get with behind the axle steering.

Thanks!


britishtrident - 15/7/13 at 07:07 AM

You can only have classical ackerman geometry (toe-out in turns) if the steering linkage has an old fashioned steering box and centre track rod
With rack & pinion steering the text book Ackerman geometry has a whole lot of other variables thrown in the main ones being the fore-aft location of the steering rack and length of the track rods.

With rack and pinion steering on front engined rwd sports cars the steering arms are usually located in front of the virtual king pin, most of the toe-out in turns is created by locating the steering rack aft of an imaginary line line drawn between the outer track rod end centres.

Strangely when the steering arms are to the rear of the virtual king pin (as on most modern FWD cars) moving the steering rack location towards the rear of the car also increases toe-out in turns.

If you can find the space and have all the suitable parts available there is nothing wrong with using rear mounted steering arms.


As for any difference in toe caused by deflection the answer is none zero, in any event if you use poly bushes the wishbones don't move much under braking loads.

[Edited on 15/7/13 by britishtrident]