Back to the basics - Trackbar/Draglink geometry

I'm in the process of building a new trackbar bracket and I'm wanting to make sure I get my angles right so I don't have bumpsteer/death wobble. I've always heard two different schools of thought on this and I'm trying to figure out the correct one. One is that if you draw imiginary lines from MOUNTING HOLE to MOUNTING HOLE for the trackbar and draglink, that they should be parallel. The second one is that the bars should be parallel (at the same degrees), so basically your measuring from the CENTER OF THE JOINT to the CENTER OF THE JOINT. These are completely different, so I'm trying to figure out the correct one.

If you take a look at this first picture you will see my draglink and a white thing I put in there that goes from the MOUNTING HOLE to MOUNTING HOLE. So is my goal to match the angle/degrees of the trackbar itself, or of the white thing which goes to the mounting holes. Different joints such as heims, TRE's, spherical (flex) joints would all change the angles.



So again, if you look at my edited picture below, is my goal to match the white line (mounting holes) or the red line (center of joint)?



To sum it up, which photo would be correct for the trackbar, the first or second?

First shows the trackbar matching the mouting hole to mounting hole for the draglink.


Second shows the trackbar matching the center of joint to center of joint of the draglink (i.e. parallel to draglink).

The drag link and track bar need to be parallel to each other.
When installing OTK steering, the track bar's axle mount needs to be move from the bottom of the axle to the top. Sometimes a dropped pittman arm is also used in addition to the raised track bar.
You need a bracket like this to move the track bar. The track bar will need to be cut, shortened and welded back together.
http://store.jksmfg.com/merchant2/m...0_925&Store_Code=JKS01&Category_Code=FABParts

lazyxj said:

The drag link and track bar need to be parallel to each other.
When installing OTK steering, the track bar's axle mount needs to be move from the bottom of the axle to the top. Sometimes a dropped pittman arm is also used in addition to the raised track bar.
You need a bracket like this to move the track bar. The track bar will need to be cut, shortened and welded back together.
http://store.jksmfg.com/merchant2/m...0_925&Store_Code=JKS01&Category_Code=FABParts

Click to expand...

Thanks, but that doesn't really answer my question. My ultimate question is what to measure from.

Those pictures above are all from my jeep. I already have the JKS over axle bracket and a shortened trackbar. My issue stems from the way I have my steering setup. Since I'm running my tie rod over the knuckle I had to move my draglink over the knuckle as well. However, it is still under the pitman arm like it is stock. So if you looked at the picture above and pictured my draglink mounted under the knuckle the angle of the draglink would change and it would now match the angle of the white piece in the picture. Thus, I'm just trying to find out where to measure from. It seems to me that you're supposed to measure from mounting hole to mounting hole because there is too much varience in OTK vs UTK or TRE's vs. heims or flex joints etc. All of this would change the angle of the draglink/trackbar. I hope that all makes sense...

The second (last) photo show both bars to be parallel, the way it should be. Sorry about the confusion, I didn't notice the raised track bar bracket.
Tired eyes.

One last picture to try to show what I'm talking about. This picture is of my Jeep and how I previously had my trackbar and draglink. While the bars themselves are parallel, I'm pretty sure that the geometry is incorrect. The bars are parallel but this is because my draglink is mounted OTK. But if you look at the pic below which shows the line connecting mounting hole to mounting hole for the draglink, the angles are not parallel.

northwestxj said:

One last picture to try to show what I'm talking about. This picture is of my Jeep and how I previously had my trackbar and draglink. While the bars themselves are parallel, I'm pretty sure that the geometry is incorrect. The bars are parallel but this is because my draglink is mounted OTK. But if you look at the pic below which shows the line connecting mounting hole to mounting hole for the draglink, the angles are not parallel.

Click to expand...

Everything in this picture looks spot-on IMO.

The pic looks spot on,the lines are wrong,its always center of joint to center of joint.It doesnt make any difference whether its a bolt,a heim, or a tre.

RCP Phx said:

The pic looks spot on,the lines are wrong,its always center of joint to center of joint.It doesnt make any difference whether its a bolt,a heim, or a tre.

Click to expand...

yeah x2, its measured through the pivot of the joint , not through the mounting hole...

Did you have bump steer and/or death wobble at some point? Why are you redoing your Track Bar setup?

Two other details to take into consideration:

1 - You want your track bar to be as flat as possible. There will be less lateral axle movement with flatter orientation. Also the longer the overall length the better.

2 - In addition to the Drag Link and Track Bar being parallel, common theory is you want them both to be as close to the same length as possible. Equal length allows both angles (or links) to follow along the same axis resulting in minimal lateral axle movement once again.

These are some key details I've found in my research of steering geometry. I'm no expert, but when I redo my Track Bar setup I plan to take the above guidelines into consideration. And yes, with my current setup I do have bump steer and it's some scary chit sometimes.

Here's some additional good reading:

http://bulletproofsteering.com/geometry.html

Scott

northwestxj said:

One last picture to try to show what I'm talking about. This picture is of my Jeep and how I previously had my trackbar and draglink. While the bars themselves are parallel, I'm pretty sure that the geometry is incorrect. The bars are parallel but this is because my draglink is mounted OTK. But if you look at the pic below which shows the line connecting mounting hole to mounting hole for the draglink, the angles are not parallel.

Click to expand...

Measure "point of pivot" to "point of pivot". The drag link pivots on the ball part of the TRE (at the knuckle), not the mounting hole for the TRE stud.
The orientation of the track bar and drag link in your picture is pretty good. You still will have bump steer, however, but probably not serious on the highway. The reason being the track bar is significantly shorter than the drag link.

xjbubba said:

Measure "point of pivot" to "point of pivot". The drag link pivots on the ball part of the TRE (at the knuckle), not the mounting hole for the TRE stud.
The orientation of the track bar and drag link in your picture is pretty good. You still will have bump steer, however, but probably not serious on the highway. The reason being the track bar is significantly shorter than the drag link.

Click to expand...

That makes sense, and that's what I'll do, thanks. Thanks to everyone else too.

Seiler said:

Did you have bump steer and/or death wobble at some point? Why are you redoing your Track Bar setup?

Two other details to take into consideration:

1 - You want your track bar to be as flat as possible. There will be less lateral axle movement with flatter orientation. Also the longer the overall length the better.

2 - In addition to the Drag Link and Track Bar being parallel, common theory is you want them both to be as close to the same length as possible. Equal length allows both angles (or links) to follow along the same axis resulting in minimal lateral axle movement once again.

These are some key details I've found in my research of steering geometry. I'm no expert, but when I redo my Track Bar setup I plan to take the above guidelines into consideration. And yes, with my current setup I do have bump steer and it's some scary chit sometimes.

Here's some additional good reading:

http://bulletproofsteering.com/geometry.html

Scott

Click to expand...

I currently have death wobble, yes. This is one of the reasons I'm re-doing my setup. I've been running this setup for quite some time, but the problem is the mounting holes for my trackbar bracket are too large and are starting to oval as well. I think this is leading to death wobble as I've checked or replaced everything else.

The other issue is my trackbar hits my diff cover on full bump. In order to fix this, I'm going to build the new one so it mounts 1.5" forward on the frame, which should fix the contact issue.

Thanks for the guidelines you mentioned. I've heard them before and am trying to take them into consideration but unfortunately I can't change it too much more than it already is. I am going to try to make the bar slightly longer but I don't want to change the trackbar axle bracket at this time...

northwestxj said:

I'm in the process of building a new trackbar bracket


Second shows the trackbar matching the center of joint to center of joint of the draglink (i.e. parallel to draglink).

Click to expand...

why dont you get a flat drop pitman arm?

ZJs are the most drop
then XJs then YJs then TJs

wjs are really cool, more throw but the taper is wrong. (there almost flat)



why dont you suck your arms back in to stop the track bar from hitting?