Bump steer fix! will this work?

OLD


the fix


FYI I do have a hy steer arm. o and the drag link angerl is not as steep on the jeep as in pic just messed that up but they will be parallel. What do yall think, from what i have gathered off this forum this should work but then again i could have miss inturpreted everything i have read. as of now i have wicked bad bump steer, Thanks

WIll

I may be wrong, but I thought the trac bar had nothing to do with bump steer. I though it was the angle between the tie rod and drag link. When the suspension compresses and the axle moves up, it forces the drag link up which in turn forces the steering wheel to turn. Again, I may be totally off, but by using a drop pitman arm, this will lower the drag link, reduce the angle, and minimize bumpsteer.

no actual expuierence, but your drawings look good to me, as the track bar and tie rod angles should be identical, so that the suspention will flex and liftboth evenly and not force the steeringwheel to one side (and the wheels)


does that make sense to me? im not sure...
ahhh good ol posting at 1:15am while the roomate is up watching fight club.... mmm mmm good eats

agreed that looks like a good fix in theory. how do you propose to attach the TB to the axle now? are you gonna try and use the UCA brace? fab up something else to flank it? it just seems from your drawing that you're gonna end the TB right where the UCA ties in (assuming theres a hint of 'to scale' in there)...may be an interesting idea. what type of bar will you be using, just a DOM tube, or gonna try to get an adj TB of some sort to work in there?
-Bennett

Oh hey, they reminds me Bennett, one of my friends has a custom setup for his 8" lift. He used the UCA mount for the trac bar as you mentioned, and instead of short arms he obviosly used long arms. Its just a straight and small trac bar like the drawing. I'm not sure about bumpsteer, but I know he can lift the body and the coils will fall out, hows that for flex.

Damn noobs are overrunning this place!

COXJ, what you propose to do will definately work, at least for street purposes. Ideally the trackbar and draglink will be parrallel, in the same plane, and of equal length. However as long as they're parrallel you will have eliminated bumpsteer on the road, although you may experience some axle shift under extreme articulate since the trackbar is so short. My setup is nearly identical to your "fix" drawing as I'm running a hy-steer arm as well.



You can kinda see the trackbar bracket hiding behind the draglink in that pic. HTH

Ary

thats what i wanted to here. and as for mounting the track bar i am going to just use a couple plates like in the drawing of 1/4 in plate and box them in for strength. and as for mounting it to the uca mount well i have no pass side uca so its no big deal. and i to and most everyone on this list that runs shocks longer than 11in travel can drop a coil if you dont extend your upper bump stops.

WIll

I may be wrong, but I thought the trac bar had nothing to do with bump steer. I though it was the angle between the tie rod and drag link. When the suspension compresses and the axle moves up, it forces the drag link up which in turn forces the steering wheel to turn. Again, I may be totally off, but by using a drop pitman arm, this will lower the drag link, reduce the angle, and minimize bumpsteer.

Click to expand...

Just so you know, that is completely wrong. using a drop pitman arm with out modifying the track bar angle will worsen bumpsteer, not cure it.

MSHarnett said:

I may be wrong, but I thought the trac bar had nothing to do with bump steer. I though it was the angle between the tie rod and drag link. When the suspension compresses and the axle moves up, it forces the drag link up which in turn forces the steering wheel to turn. Again, I may be totally off, but by using a drop pitman arm, this will lower the drag link, reduce the angle, and minimize bumpsteer.

Click to expand...

You are very wrong. Here is a defintion of bump steer.

Lawn Cher' 7-8-04 said:

Bump steer is when compression of the front suspension, such as occurs when hitting a bump, causes the steering wheel to move, hence the name. This is usually caused by the drag link and the track bar (aka panhard rod) not travelling in the same arc, thus one of the links in the system is forced to move laterally (the drag link will move, rotating the pitman arm, backfeeding the steering gear, turning the steering shaft and steering wheel, since the two ends of the track bar are mounted with fewer degrees of freedom.) When the track bar and drag link are parallel and of equal length, they swing smoothly together as the suspension cycles, maintaining parallelism and eliminating bumpsteer.

Click to expand...

Well.. I was wrong, but not way off. At least you showed me what I was wrong about. So then, let me get this straight, if a PDA doesn't fix bumpsteer, WHAT DOES?

ok, given the last graphic, does the fact that using hi-steer eliminate the bumpsteer and the fact that the draglink connection to the knuckle and the tracbar connection to the axle have nothing to do with it?

i was running almost an identical setup but didn't have hi-steer.. draglink straight to the knuckle and connected using heims. my t-bar mount was considerable lower too... maybe 2-3"? it was still sitting on top of the axle though. the draglink and trackbar angles were dead on even but the difference between the end of the tracbar and the end of my draglink to the knuckle were almost 10". i had HORRIBLE bumpsteer. like i said though, there was no possible way my angles could have been any closer.. they were perfect.

i swapped knuckles (my old ones were drilled out to 5/8" to accomodate hiems) and fabbed up a new tracbar mount to go under the bucket (back to the stock location) and my bumpsteer is gone. so given from my personal experience of using both routes, it seems that your t-bar connection needs to be as close to the knuckle connection as possible.

i can only assume that that's why RE's 1660 tracbar angle is flattened on the axle end... to help it get under the bucket more and closer to the knuckle.

am i way off here and if so, what am i not seeing?

i've gotten rid of that steering setup now and have gone with the ZJ stuff and i'll never look back.

minus one, the idea is to have them perfectly parallel and the same length. If they're close to parallel and the same length you will not have much bumpsteer. If you have them at the same angle, but not close to the same length, and they are at a steep angle relative to the ground, you will get more bumpsteer because as the axle moves up and down the short track bar causes much greater side-to-side shifts.

Additionally, the angle of each link is determined by drawing a line from the connection points of the link, not by the shape of the bar itself(in reference to shape of RE bar above).

In a perfect world the trackbar and draglink would be the same length and perfectly flat. This is hard to do on many vehicles due to the inherent design limitations placed on you by the vehicle's frame and factory designs.

I hope that made some sense.

Ary

Ary..

that definitely made all the sense!

the steepness of the angles is where i was getting thrown off. it looks like i was relatively close on everything else... i can totally see that now and how it'd make the axle want to rotate more instead of being pushed up more into the frame. that's where the hi-steer comes into play... it helps to flatten everything out.

the only thing i was getting at with the RE thing was that it helped you get that connection closer to the connection at the knuckles... help out with the length.

thanks man!