Usable Articulation

[Mike_H]

I don't have a rear track bar anymore, so I can't help much there.

I know the gas tank cross member can be trimmed to clear the bracket. Even with a relocation bracket, mine wasn't an issue when I had it. Stock arms, body lift and 1" of rear bump stop all factored into that. My rear was bump stopped for the shocks.

2003 Rubicon

This is interesting... Your track bar didn't hit at all? All TJs are different. Mine hits hard enough that it's not a simple grind for clearance. I'd have to get the cutting wheel out. However... My shocks don't come anywhere near hitting the lower spring perch... Which I know some guys have trouble with. Might be the shocks (Bilstein 5100's).

 

[jjvw]

This is interesting... Your track bar didn't hit at all? All TJs are different. Mine hits hard enough that it's not a simple grind for clearance. I'd have to get the cutting wheel out. However... My shocks don't come anywhere near hitting the lower spring perch... Which I know some guys have trouble with. Might be the shocks (Bilstein 5100's).

Is your pinion raised? Mine wasn't. Later, when I raised the pinion I did a bunch of spring mount work at the same time which coincidentally allowed the shocks to clear. I lost the track bar at the same time.

2003 Rubicon

 

[bobthetj03]

I have a rear TB, so this is my setup. 2.5" lift springs. RC adjustable rear TB, Angled relocation bracket, 1 5/8" bump stops. My RS5000X shocks clear at full bump.

My RB relocation bracket does not. No BL.

Only one mod can change this. Yep, a BL. Also, the TB is now kissing the rear gas tank skid.

 

[Mike_H]

Is your pinion raised? Mine wasn't. Later, when I raised the pinion I did a bunch of spring mount work at the same time which coincidentally allowed the shocks to clear. I lost the track bar at the same time.

2003 Rubicon

Nope. Factory control arms.

 

[bobthetj03]

We have to remind ourselves that @jjvw 's setup is far from factory at this point, but he has done the homework and knows the skinny.

 

[Thunderhead]

I have a rear TB, so this is my setup. 2.5" lift springs. RC adjustable rear TB, Angled relocation bracket, 1 5/8" bump stops. My RS5000X shocks clear at full bump.
View attachment 36685 View attachment 36686
My RB relocation bracket does not. No BL.
View attachment 36687 Only one mod can change this. Yep, a BL. Also, the TB is now kissing the rear gas tank skid.

I haven’t seen any photos of the dimples on your Jeep. How does it look ?

 

[bobthetj03]

I haven’t seen any photos of the dimples on your Jeep. How does it look ?

Dimples? What are you talking about?

 

[Thunderhead]

This is a fascinating read, guys. Please...go on... :icon_popcorn:

I know ! I thought they were getting down :dancer2:

 

[Thunderhead]

Dimples? What are you talking about?

Oh. Your BL. Your crack. The 1/2 inch. I guess I just made myself laugh calling it dimples

 

[bobthetj03]

Oh. Your BL. Your crack. The 1/2 inch. I guess I just made myself laugh calling it dimples

You slay me brah! Need I remind you where your front locker button is?

 

[jjvw]

What are some things we need to watch out for as the axle droops? An example would be stretched brake lines.

2003 Rubicon

 

[Rob5589]

What are some things we need to watch out for as the axle droops? An example would be stretched brake lines.

2003 Rubicon

Drive shafts, brake hoses, springs unseating

 

[bobthetj03]

Making sure that your shocks are not your limit straps.

 

[jjvw]

Drive shafts, brake hoses, springs unseating

Drive shafts are the big one and might be the most difficult to address, especially when raised skid plates are a part of the build. The total usable travel should take into consideration the usable travel of the drive shaft. Super short slip yoke eliminators, wheel base stretches, shorter shocks and limit straps might be needed to increase or limit down travel based on what the driveshaft allows. Maintaining good u-joint angles up front with enough caster is also a relatively common problem, though I haven't had to deal with that on mine.

Making sure that your shocks are not your limit straps.

If the shocks aren't the limit to down, then what is for most people? FWIW, my shocks are my limit straps. Always have been. That is a topic worth discussing, even for my own benefit. If it becomes necessary, I am considering adding a rear center limiting strap on mine.

 

[bobthetj03]

Weather is supposed to warm up this week, so with that, I'll do some fork lift flecks-ing to note some limitations and find my "usable articulation". Anything in particular that anyone wants to see pics of chime in.

 

[Serbonze]

Interesting discussion. I just swapped out shocks (and added an Antirock) yesterday from Bilstein 5100s to Rocksports. The fronts, paired with the Currie 4” coils provide a tremendous amount of travel. The Metalcloak front trackbar still clears the front diff cover by about one half inch with the axle stuffed and the shocks collapsed. I had no interference with any components. The Currie springs and Rocksport shocks seem to work very well together.

 

[jjvw]

I've been wondering if the MC Rocksports are rebranded Old Man Emu. There measurements are very similar.

Both are interesting with regard to travel. Short compressed lengths for the amount of overall travel they provide, compared to other options.

2003 Rubicon

 

[Serbonze]

I tried to find as much information as I could, but not many people are using them in the TJ community. I called MC several times hoping to get answers, but each one was “they are very similar to OME”. I was able to get a set for a really good price so I just decided to try them. My only goal of the swap was to try and take the edge off of the small event harshness of the Bilsteins, and if I was also able to gain some additional usable travel then that was a bonus. The rears have much more up than down which is something that I may need to experiment with, but for my use right now I’m not overly concerned.

 

[jjvw]

... The rears have much more up than down which is something that I may need to experiment with, but for my use right now I’m not overly concerned.

Up travel is a good thing. More important and more useful than lots of down, IMO.

 

[chitown35]

A softer longer spring that is still seated would provide more down force than just the weight of the axle alone. The longer the reach, the less "push" until there is none and the spring is free.

2003 Rubicon

a 200 in. lb. spring will give more down force to the axle than a 140 in. lb. spring will, until the spring is at an unloaded state, in which case you've reached maximum usable articulation. So, the softer spring will let the axle droop further before it reaches an unloaded state, but how much additional traction did it provide you just because the tire is still hitting the ground?

It seems like a longer spring is desirable. But doesn't this sound like the firmer rate is better? Is a softer spring rate the only way to achieve a longer spring length at the same ride height? Or could the spring also have a different winding rate or diameter?