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Ok, here's one for the gurus. Will a front triangulated 4-link (standard 2 uppers, 2 lowers) work any differently in regards to bump steer when compared to good old leaf springs (be it SUA or SOA) on a non-hyrdro steered rig? (And why)

Given the simple of example of hitting a speed bump, this is how I see the different setups functioning:

A 3-link of some sort with panhard would be optimal to prevent bump steer since when properly setup it would force the axle to travel in an arc that allows the drag link to remain constant length in relation to the steering knuckles, thus preventing bump steer.

Running a 4-link in the front will cause bump steer to some degree since the suspension will travel straight up and down while the drag link would travel in an arc causing the bump steer.

With the garden variety no track bar leaf sprung suspension the leaves will have the natural tendency to also travel straight up and down in this situation, so it would behave very similarly to the 4-link.

So, to take this somewhere, I'm thinking that the same basic rules apply to keeping bumpsteer to a minimum between a 4-link front suspension and leaf springs. Having a flat drag link will minimize bump steer, and if you were to have excessive slope on the drag link you would see more bumpsteer.

So in the world of trade-offs, if you can't do full hydro and can't do a panhard, you better keep the drag link as flat as possible to make the best of it.

Am I thinking right on this? It seems to make sense to me, but I want to get some opinions on this.
 

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I´m no guru, but I´d say that your thinking is correct.

Just thinking and writing off the top, there may arise complications in the bumpsteer geometry if only one of the wheels cycles up and down. OTOH, it´d still prolly behave just like a leaf suspension...........
 

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i have been thinking about the same thing except with a 3link

if you dropped the passenger side say 1 inch it would change the swing path of the axle to act like a panhard
 

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Your thinking is absolutly right, and unless you like high speed desert running I bet you would never notice any bumpsteer. Bumpsteer isnt the end of the world anyway, alot of times its just a minor inconvinience.
 

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Ok I decided to throw some numbers into this to help quantify the amount of bump steer. Assuming a 36" long draglink parralel to the ground. If the link were to deflect 10 degree's the effective horizontal distance from the pitman arm to the knuckle would now be 35.45", so the draglink would pull the knuckle .55" over. Now to cause 10 degrees of deflection you would have to compress the suspension 6"!!! So even if you hit a big bump you wouldnt see alot of bump steer on the street.
 
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