POLL: Which track bar should i get?

[bobthetj03]

Good questions. I wish I understood all you were saying. I hope some others chime in. I thought all I'd need is my SS SYE, DC and double adjustable uppers so I could rotate my pinion to face directly at my yoke. That solves the main angle problem we're dealing with, right? Just tuck that momma. It would be so cool. Just look at all the pics on here of TJ's and that awful skid plate hanging down. I hate'em as much as @bobthetj03 hates body lifts! And that's a lot of hate!

The hate is strong with this one, it's true. Ok, let's look at the rear suspension. Your TB mounts to the frame at one end, and the axle at the other at a certain vertical angle. You lift the jeep 2.5", you are creating more vertical angle to the TB. You need to correct that. This is where the relocation bracket comes in. Secondly, because of the lift, the axle is shifted to one side and is off center. Since the relocation bracket restores the TB's geometry, it also brings the axle back closer to center. Bad part about that stupid bracket? It limits your up travel by hitting the tub if not bump stopped correctly. Didn't think that bracket would be an interference issue, did ya?

 

[Starrs]

Does AEV make a trackbar?
Lol

 

[bobthetj03]

Does AEV make a trackbar?
Lol

I just found out yesterday that Nth Degree makes coil springs, lol!

 

[JMT]

The hate is strong with this one, it's true. Ok, let's look at the rear suspension. Your TB mounts to the frame at one end, and the axle at the other at a certain vertical angle. You lift the jeep 2.5", you are creating more vertical angle to the TB. You need to correct that. This is where the relocation bracket comes in. Secondly, because of the lift, the axle is shifted to one side and is off center. Since the relocation bracket restores the TB's geometry, it also brings the axle back closer to center. Bad part about that stupid bracket? It limits your up travel by hitting the tub if not bump stopped correctly. Didn't think that bracket would be an interference issue, did ya?

Hmm...so rear adjustable TB and call it good. I’ll take a look under and will discover my limiting factor when I cycle the suspension. Thanks!

 

[Mike_H]

I'll try to work my way through it with Pictures. I'm kinda thinking through it in my own mind too, so this will be helpful. I'm using Paint, so excuse the scale and lack of detail. This is the "stock" configuration. I'm not showing tires or springs...

Ok, now, Next picture, I'll show you what happens when you rotate the axle, to do a DC driveshaft, but with NO correction Geometry.

Now, the shocks are getting into the axle tube...and I just realized that I drew them upside down compared to a TJ. The trackbar is also at a funny angle...when you rotate the axle, all the mounting points on the axle rotate down and toward the back of the vehicle, but the mounting points on the frame stay the same. So...What do "They" do? They make "brackets" for the easy solution. I envision they would look something like this...brackets shown in red.

Now, I've added these brackets and extended all these forces AWAY from where they were initially designed to be. That is what is called a moment arm in engineering parlance. It multiplies force...like getting a longer wrench when you are working on a stubborn bolt. Means that shock is not reacting the same as it did in its factory location, or the track bar has a pretty good chance of tearing that control arm mount OFF the axle. That is why I think to REALLY pull this off, you are re-engineering mounting locations.

I'm not even talking about the spring perches, which already force the springs in an arc. Rotating the axle only amplifies this effect, which is why you see guys cutting and rewelding their spring perches.

I dunno...MAYBE the aftermarket suspension companies are coming up with strong, robust solutions, validated by testing....but I doubt it. That kind of engineering is EXPENSIVE (I worked in that world). People won't pay for it. I believe one of the reasons Currie and Savvy command the price that they do, is that they are doing some of that work. Maybe this is all bubpkis...I don't know. Random musing of a bored engineer who thinks about his jeep WAY too much.

 

[Squatch]

Amen brotha'... My TJ gives me grey hairs trying to work all this stuff out. Especially since I can't just throw a part at it and then dump it if it doesn't work out. Sometimes that stock '03-'04 TJR is really appealing. 31x10.50's, a Warn winch, a CB and call it good. Pop some popcorn, sit back and watch the show.

But why just watch the show when you're such an integral character in it? You'd miss it. Your wife would buy you another project just to get you outta the house! Wives are funny like that...

 

[Daz7]

It's a trackbar.....

Just has to be adjustable, suit your lift and miss other components throughout its travel. The only difference between all of them is they either have some kind of rod end or a bush.

Rule of thumb:
• The bushes will be longer living, standard rubber bushes will flex more than poly type bushes. Rubber will also transmit less NVH than both poly or whatever type of rod end might be used.
• The Rod end types will require more maintenance/replacement. Might allow a tiny bit more flex before binding, wiil transmit more NVH than either of the Rubber or poly bushes.

 

[JMT]

The hate is strong with this one, it's true. Ok, let's look at the rear suspension. Your TB mounts to the frame at one end, and the axle at the other at a certain vertical angle. You lift the jeep 2.5", you are creating more vertical angle to the TB. You need to correct that. This is where the relocation bracket comes in. Secondly, because of the lift, the axle is shifted to one side and is off center. Since the relocation bracket restores the TB's geometry, it also brings the axle back closer to center. Bad part about that stupid bracket? It limits your up travel by hitting the tub if not bump stopped correctly. Didn't think that bracket would be an interference issue, did ya?

This post is the advantage of a ‘pace yourself build.’

 

[JMT]

I'll try to work my way through it with Pictures. I'm kinda thinking through it in my own mind too, so this will be helpful. I'm using Paint, so excuse the scale and lack of detail. This is the "stock" configuration. I'm not showing tires or springs...
View attachment 29841

Ok, now, Next picture, I'll show you what happens when you rotate the axle, to do a DC driveshaft, but with NO correction Geometry.
View attachment 29843


Now, the shocks are getting into the axle tube...and I just realized that I drew them upside down compared to a TJ. The trackbar is also at a funny angle...when you rotate the axle, all the mounting points on the axle rotate down and toward the back of the vehicle, but the mounting points on the frame stay the same. So...What do "They" do? They make "brackets" for the easy solution. I envision they would look something like this...brackets shown in red.
View attachment 29844

Now, I've added these brackets and extended all these forces AWAY from where they were initially designed to be. That is what is called a moment arm in engineering parlance. It multiplies force...like getting a longer wrench when you are working on a stubborn bolt. Means that shock is not reacting the same as it did in its factory location, or the track bar has a pretty good chance of tearing that control arm mount OFF the axle. That is why I think to REALLY pull this off, you are re-engineering mounting locations.

I'm not even talking about the spring perches, which already force the springs in an arc. Rotating the axle only amplifies this effect, which is why you see guys cutting and rewelding their spring perches.

I dunno...MAYBE the aftermarket suspension companies are coming up with strong, robust solutions, validated by testing....but I doubt it. That kind of engineering is EXPENSIVE (I worked in that world). People won't pay for it. I believe one of the reasons Currie and Savvy command the price that they do, is that they are doing some of that work. Maybe this is all bubpkis...I don't know. Random musing of a bored engineer who thinks about his jeep WAY too much.

Well, think about it way too much or not, nice work. You explained it well to a TJ newb or addict, whatever. Actually , turning that rear shock upside down as you drew it solves the problem of a relocation bracket by giving a bit more clearance. Brilliant mistake. LOL. Just make sure you can run the shocks upside down.

 

[Squatch]

Just make sure you can run the shocks upside down.

Like this? LOL

 

[JMT]

The hate is strong with this one, it's true. Ok, let's look at the rear suspension. Your TB mounts to the frame at one end, and the axle at the other at a certain vertical angle. You lift the jeep 2.5", you are creating more vertical angle to the TB. You need to correct that. This is where the relocation bracket comes in. Secondly, because of the lift, the axle is shifted to one side and is off center. Since the relocation bracket restores the TB's geometry, it also brings the axle back closer to center. Bad part about that stupid bracket? It limits your up travel by hitting the tub if not bump stopped correctly. Didn't think that bracket would be an interference issue, did ya?

Looks like I have 4-5” above the trackbar on the driver side. With 2” bumpstop I have about 4” of space from the jounce to the perch. So I see what you mean. It may not be the limiting factor, the tire width may be if it hits the stock flares, but in any case, thanks for the lesson.

 

[bobthetj03]

@Ranger_b0b explained it pretty much how it is. How many of us Jeep owners would go thru the expense of re-designing the suspension to work as Jeep intended to work. Not many.

 

[StG58]

Well, think about it way too much or not, nice work. You explained it well to a TJ newb or addict, whatever. Actually , turning that rear shock upside down as you drew it solves the problem of a relocation bracket by giving a bit more clearance. Brilliant mistake. LOL. Just make sure you can run the shocks upside down.

One of the bigger problems is that shocks aren't valved 50/50.

Like this? LOL

That's one way to do it...

 

[StG58]

I'll try to work my way through it with Pictures. I'm kinda thinking through it in my own mind too, so this will be helpful. I'm using Paint, so excuse the scale and lack of detail. This is the "stock" configuration. I'm not showing tires or springs...
View attachment 29841

Ok, now, Next picture, I'll show you what happens when you rotate the axle, to do a DC driveshaft, but with NO correction Geometry.
View attachment 29843


Now, the shocks are getting into the axle tube...and I just realized that I drew them upside down compared to a TJ. The trackbar is also at a funny angle...when you rotate the axle, all the mounting points on the axle rotate down and toward the back of the vehicle, but the mounting points on the frame stay the same. So...What do "They" do? They make "brackets" for the easy solution. I envision they would look something like this...brackets shown in red.
View attachment 29844

Now, I've added these brackets and extended all these forces AWAY from where they were initially designed to be. That is what is called a moment arm in engineering parlance. It multiplies force...like getting a longer wrench when you are working on a stubborn bolt. Means that shock is not reacting the same as it did in its factory location, or the track bar has a pretty good chance of tearing that control arm mount OFF the axle. That is why I think to REALLY pull this off, you are re-engineering mounting locations.

I'm not even talking about the spring perches, which already force the springs in an arc. Rotating the axle only amplifies this effect, which is why you see guys cutting and rewelding their spring perches.

I dunno...MAYBE the aftermarket suspension companies are coming up with strong, robust solutions, validated by testing....but I doubt it. That kind of engineering is EXPENSIVE (I worked in that world). People won't pay for it. I believe one of the reasons Currie and Savvy command the price that they do, is that they are doing some of that work. Maybe this is all bubpkis...I don't know. Random musing of a bored engineer who thinks about his jeep WAY too much.

LOVE it! Now, if we just had a 3D model of a TJ to play with, we might be able to figure all this out.

Edited to add: Hmmm...rear bracket kits are about $250 or so. What about rotating the axle, but not the suspension? What does that buy us?

 

[Mike_H]

LOVE it! Now, if we just had a 3D model of a TJ to play with, we might be able to figure all this out.

Awe man....I happen to have Solidworks on my laptop...and I know how to use it. Don't tempt me. Actually, I've thought about it before. Problem is that I have NO way to really measure a frame, so there would be a lot of measurements taken by my hairy eyeball...So...the model would be worth exactly what anyone would pay for it...Would be fun to play with though. I wonder if we formed a coalition of sorts intent on making new aftermarket parts for the TJ, if we could get any support from Chrysler Corp...They have it all, and I'm sure the aftermarket companies don't reinvent the wheel.

Coming back around to my idea with the SYE...I've got a Rubicon, so that particular item doesn't affect me, but me thinks there is a way to gain a benefit from a shorter output, but NOT have to go through the rig-a-ma-roll of a DC driveshaft. Might start another post on it, just for shits and giggles.

 

[bobthetj03]

Engineers? CAD drawings?

 

[StG58]

Engineers? CAD drawings?

Yup. With experience and common sense thrown in. And major peer review.

 

[StG58]

What happens if we rotate the axle, but not the suspension? i.e. weld new brackets on an appropriately rotated axle?

 

[Mike_H]

What happens if we rotate the axle, but not the suspension? i.e. weld new brackets on an appropriately rotated axle?

That's the "correct" way to do it. Then you follow the OEM's intent and benefit from the extensive life cycle testing they do. Seems though that there is a very good reason to outboard the shocks...something about getting them more upright, so the forces are more "true" vs the angle they are at.

 

[bobthetj03]

What happens if we rotate the axle, but not the suspension? i.e. weld new brackets on an appropriately rotated axle?

Crawl under your jeep, look up at your control arm brackets and your axle, and your drive shaft. Oh, and take a look at your transfer case, muffler, and TC skid. Damn it! I got like 2" of clearance if I shove my TC up. Damn it! My muffler is going to hit the skid! Crap! I have to rotate my pinion even more now. Shit, now my shocks are hitting the spring perch! Vibes? Why is it so noisy now? Ugh! Tummy tucks are so easy!