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Five bar suspension system.

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#1 mariner

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Posted 24 May 2020 - 18:18

This is probably old hat as they say but stuck in lockdown I went back to some old stuff and wondering if the Z bar spring system used in the 1960's by Porsche among others still had any potential if complemented by an anti-pitch fifth spring?


The Z bar is an alternative to coils and it is Z shaped anti roll style bar which provides only single and double bump stiffness. It's used with a conventional anti roll bar which provides all the roll stiffness ( and some single bump stiffness).


If you link the mid-points of the front and rear anti roll bars with another Z bar this provides full pitch control but nothing else - except a small degree of warp control as the movement of a front left bump and a right rear bump on the centre points of each anti roll bar will trigger a reaction  to warp.


Of course it may , or may not, be desirable to largely isolate bump and  roll resistance at each end?


Also the clever bit would be to arrange the damping forces in a similar manner - maybe by adding  a damper near each end of the Z shaped anti pitch link bar to control  pitch?




#2 Fat Boy

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Posted 26 May 2020 - 17:51

I only know of Z- bars on Formula Vee cars, which I've never worked on. They're a third spring, nothing more. In those cars, keeping the ride consistent without adding a bunch of roll resistance is beneficial because of the horrible realities of the swing-axle suspension. If you were going to damp it, you'd locate the damper in the middle of the ARB, so it moves in pure heave, but is stationary in roll.


At least, that's my initial thoughts.