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what am I doing wrong with this traction bar setup?

Scottie

Well-known member
Joined
Mar 25, 2023
Member Number
6319
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88
Loc
Seattle Wa
Putting a slip and twist style traction bar in a YJ. Seems to really be limiting flex. I know shackle style are more common, but I have seen these done before.

When the traction bar is installed it will not settle down to ride height. There seems to be alot of bind going on.



Thanks!
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Arickvan said:
if you unbolt the hiem and set the rig on the ground, does the traction bar still line up with everything so that the hiem can still bolt right back in?
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No it does not. If you unbolt heim and travel to full bump. It will dang near touch the tub.

Should it have been mocked up at ride height? Still seems like it would bind once the suspension compressed or drooped, causing the same bind.
 
Scottie said:
No it does not. If you unbolt heim and travel to full bump. It will dang near touch the tub.

Should it have been mocked up at ride height? Still seems like it would bind once the suspension compressed or drooped, causing the same bind.
Click to expand...
I'm not familiar with the slip and twist style, but that sounds like why it wont settle down
 
Scottie said:
No it does not. If you unbolt heim and travel to full bump. It will dang near touch the tub.

Should it have been mocked up at ride height? Still seems like it would bind once the suspension compressed or drooped, causing the same bind.
Click to expand...

Yes. If you mocked it up at full droop, when you compress the suspension the bar thinks that full droop is actually ride height and it's binding up/jamming because it's running out of angle and there isn't enough slip to accommodate.

Look at your picture. There no where for the bar to go. As the rear goes up (compresses) your heim would have to come down for the bar to slip. It can't do that, so you're binding up.

You can try greasing the shit out of it, because it looks dry, which isn't helping either. As was said, metal to metal doesn't slide for nothing. That might get a little more out of it. At the end of the day, you're going to have to cut those mounts off and re-mock it.

Actually... Can you flip the bar? Bottom axle mount on the top and vice versa? It sound stupid but I'm looking at this and it looks like it would lengthen you droop slide to get you closer to where you need to be if the mounts will line up.
 
westracing01 said:
Yes. If you mocked it up at full droop, when you compress the suspension the bar thinks that full droop is actually ride height and it's binding up/jamming because it's running out of angle and there isn't enough slip to accommodate.

Look at your picture. There no where for the bar to go. As the rear goes up (compresses) your heim would have to come down for the bar to slip. It can't do that, so you're binding up.

You can try greasing the shit out of it, because it looks dry, which isn't helping either. As was said, metal to metal doesn't slide for nothing. That might get a little more out of it. At the end of the day, you're going to have to cut those mounts off and re-mock it.

Actually... Can you flip the bar? Bottom axle mount on the top and vice versa? It sound stupid but I'm looking at this and it looks like it would lengthen you droop slide to get you closer to where you need to be if the mounts will line up.
Click to expand...
That was one of my guesses, that it needed to be mocked up at ride height. However, i don’t see how it wont have binding once suspension starts to compress or droop from ride height. Seems like once it leaves the point where everything is lined up, it will have some amount of bind to it.

If that is the fix then I can refit it at the bushing end so it lines up at ride height. It is just tacked together.
 
Just so the picture is clear, the slip is not bottomed out. it has about 5” of slip available in that picture.
 
It would seem that having it parallel with the driveshaft would help prevent binding.
It would be easy to weld the slip and convert this to a shackle style if all else fails.
 
You built the track arm with the rig on a two post and the axle hanging, yes?

My opinion is a track bar is supposed to contain axle wrap rather than eliminate it. Rubber bushings, Johnny Joints or the like will let it roll a bit and allow your suspension to move. The real issue I see is that if the bar was built with the axle hanging at full droop, the moment you start setting the weight of the rig down and the axle moves upward toward the frame it begins trying to rotate the axle housing. Because the axle cannot roll at all it wants to hold the rig up in the orientation it was in hanging. The result is any upward movement of the axle housing will immediately try to rotate the housing. The pinion will want to rotate downward. The slip is largely irrelevant here.

To test this, remove the upper bolt on the axle side and set it back down. The unbolted rod end should move forward out of the mounting clevis significantly.
 
ZJs said:
You built the track arm with the rig on a two post and the axle hanging, yes?

My opinion is a track bar is supposed to contain axle wrap rather than eliminate it. Rubber bushings, Johnny Joints or the like will let it roll a bit and allow your suspension to move. The real issue I see is that if the bar was built with the axle hanging at full droop, the moment you start setting the weight of the rig down and the axle moves upward toward the frame it begins trying to rotate the axle housing. Because the axle cannot roll at all it wants to hold the rig up in the orientation it was in hanging. The result is any upward movement of the axle housing will immediately try to rotate the housing. The pinion will want to rotate downward. The slip is largely irrelevant here.

To test this, remove the upper bolt on the axle side and set it back down. The unbolted rod end should move forward out of the mounting clevis significantly.
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Yes it was built at full droop. You are 100% correct the forces try to rotate pinion down as it travels towards full bump.

And yes if I remove the axle top side bolt it will 100% rotate out of the pocket, hinging on the lower bolt and not bind.

Even if it was fitted at ride height, it seems to me the same exact same thing would happen as suspension compressed or rebounded.

I can certainly set it up at ride height, not a big deal. But it seems the same problem still exists.

What do you believe the solution is?
 
I believe a certain amount of bind is inherent in a track bar or radius arm setup. The only way I can see it lessened is by using joints that allow deflection. Large rubber clevite bushings would help. Going to larger rubber clevite bushings at each axle end will soak up the bind. Even more so if used at the frame end too. If you're down for a redesign of the Y, turning the upper portion of the Y connecting to the axle into control arm with a bushing connecting to the lower arm adds a fourth bind soaking point. The more bushings to eat the bind, the longer they will all live before needing replacement.

Also to add, the closer the arm is to the pumpkin, the less effect it will have on flex while still providing all the same axle wrap control.
 
I should add I'm not a leaf spring guy. There are likely more experienced folks on here regarding the subject. I have one rig with radius arms up front (Clayton) so I understand the pros and cons of the general design. And I'm on drink #3.
 
Bar needs to be mocked up at ride height. And why not run a shackle in tension. Much better set up.
 
Another vote for "you need to mock it up at ride hight, not full droop"

Cut the axle side bracket off, set it on the ground and weld it back on.
 
Iirc, slip type traction bars need to be almost parallel to the ground at ride height.
 
rockota said:
Iirc, slip type traction bars need to be almost parallel to the ground at ride height.
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I thought this was the opposite. I recall guys on the old site going slip and twist so you didn't have to have the bar parallel to the ground. I could be wrong it's been decades.

I do remember though most had a 3rd bar and they almost looked like a wishbone link. It would go from say the top of the differential over to the heim joint. Stopped the binding from left to right as the suspension traveled.
 
Like someone said, there is going to be some binding.

Mocking up at ride high means it will hopefully only bind when it's getting to full droop or full comp. Mocking up at full droop means it's starting to bind up at ride hight, much less full comp.
 
Cheepin said:
Bar needs to be mocked up at ride height. And why not run a shackle in tension. Much better set up.
Click to expand...
A second vote for adding a shackle in tension, set up at ride height. I have had one on my rig for going on 10 years. Has zero bind, and has never killed a joint.
 
Scottie said:
That was one of my guesses, that it needed to be mocked up at ride height. However, i don’t see how it wont have binding once suspension starts to compress or droop from ride height. Seems like once it leaves the point where everything is lined up, it will have some amount of bind to it.

If that is the fix then I can refit it at the bushing end so it lines up at ride height. It is just tacked together.
Click to expand...
Yes, but you'll be splitting the bind on either end. Just like tightening rubber bushings with the weight on them. Will it travel enough at full droop\compression to bind hard if you set it in the middle?
 
1UZRunner said:
A second vote for adding a shackle in tension, set up at ride height. I have had one on my rig for going on 10 years. Has zero bind, and has never killed a joint.
Click to expand...

It would still have the same problem as op if built at full droop.

I link the shackle for simplicity, but slip and twist works well and easier to package.

87manche said:
Yes, but you'll be splitting the bind on either end. Just like tightening rubber bushings with the weight on them. Will it travel enough at full droop\compression to bind hard if you set it in the middle?
Click to expand...

This is what I was trying to say.

It's going to bind, but if done correctly, it shouldn't limit travel.
 
Thanks for all the input! General consensus is refit at ride height. Sounds like it will still have some amount of bind as it approaches full bump or extension but to a much lesser extent.

Could certainly switch to shackle style, but sounds like this should work once setup correctly.
 
Byro said:
My brain can’t make this work without binding. As the suspension travels the heim will move in an arc. Even with the slip it doesn’t allow the arc movement. At least how I’m picturing it moving in my head.
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Same I need to sketch up a diagram or something, but it don't make sense to me
 
Arickvan said:
Same I need to sketch up a diagram or something, but it don't make sense to me
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Unless maybe the heim has to be in line with the leaf hanger, that way I can picture it moving in the same arc.


And at the current point you’re only another link and a panhard away from not having to run covered wagon suspension. :stirthepot:
 
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