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Track bar and tie rod: What hits, what doesn't?

jjvw

0-60 in 18 seconds
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Feb 17, 2018
6,650
Colorado, USA
So when the axles guys told me I had a "low" pinion and not a "high" one were they referring to the fact that I only have a 2" lift with no tummy tuck puts me in the low pinion group?
I'm not entirely sure what point they were trying to make. ;)

You either have a high pinion axle or a low pinion axle. What happens over on the other side with the cover is it's own discussion.
 

Alex01

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Mar 23, 2018
2,452
Martinez, CA, USA
Update. Removed trackbar and tested out drivers side. With the ranchos designed for a 2.5 inch lift I can reduce the bumps down to 1.5 and have 2.5 inches of clearance above the tire while having a fingers worth behind the tire in the wheel well.

With the current shocks I own I would need 3 inchs of bump stop. I have 3 inchs above the tire and 2 inchs behind.

Swapping to the smaller bodied shocks would lose me approximately 3 inchs of downtravel. But with the current shocks I have so much droop my spring can unseat... (dual coil mc?)

Seems like losing 3 inchs of downtravel for .5 inchs of uptravel (3 inch bump instead of 1.5) is a fairly big compromise.

Photo is with larger shocks.
20190111_213334.jpg
20190111_214110.jpg
 

jjvw

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Feb 17, 2018
6,650
Colorado, USA
What springs do you have? What is the measurement between shock mounts right when the springs unseat? What is that same measurement at bump?
 

Alex01

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Mar 23, 2018
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What springs do you have? What is the measurement between shock mounts right when the springs unseat? What is that same measurement at bump?
Springs are rubicon express 3.5 in. Full droop was 27.5 and with 1.5 bumps (minimum I can run with clearance) I was at 15 compressed length.

The spring unseats at 24 inchs of droop.
 

jjvw

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Feb 17, 2018
6,650
Colorado, USA
RE 3.5" front coils are 19" free with a 240lb/in rate.

Clayton 4" is 21.13", 165lb
MC 3.5" is 22.5", unknown
Currie 4" is 22.6", ~130lb

The Jeep seems light. I suspect all of these will result in more ride height than what you have now.

Savvy 3" was 20.25" at one time. A 1" spacer to adjust the ride height will also add that much reach.
 

jjvw

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Feb 17, 2018
6,650
Colorado, USA
Get a longer coil, raise the upper shock mount ~.75" (or add that much more BS) and use the Rancho RS55255.
15.69" compressed
10.73" travel
26.42" extended

Or leave everything as is and use the RS55339 with a 1/2" spacer to the shock mount.
14.43" compressed
9.41" travel
23.84" extended
 
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Alex01

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Mar 23, 2018
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Get a longer coil, raise the upper shock mount ~.75" (or add that much more BS) and use the Rancho RS55255.
15.69" compressed
10.73" travel
26.42" extended

Or leave everything as is and use the RS55339 with a 1/2" spacer to the shock mount.
14.43" compressed
9.41" travel
23.84" extended
I currently own both of those shocks :lol:. Im going to stick with the larger shock, increase the bump to 3 inches, and buy new springs the short term.

The extended length does not factor in the rubber grommet that sandwhiches the stem. The actual extended size of the rs55339 is 1 inch longer once you factor that piece into the equation.

With that piece being counted would the amount I would need to add to the mount be roughly 2 inches?
 
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jjvw

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Feb 17, 2018
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Colorado, USA
...

With that piece being counted would the amount I would need to add to the mount be roughly 2 inches?
Roughly. The rubber compresses a bit once tightened. Get a good measurement of what the compressed shock is. Run the axle up to bump and make the upper mount match.
 
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Gollywomper

TJ Enthusiast
Feb 9, 2019
337
Corning CA
I have a very similar setup to yours. RE 3.5 lift, MC track bar. My front springs brand is unknown. Were you able to get down to 1.5” of bump stop with out any track bar interference? That’s with both tires stuffed at same time/ full bump?
 

strumble8

TJ Enthusiast
Dec 27, 2018
259
Strasburg Co.
This is how I modified my upper shock mount on the front with the ranch rs55255 shocks. I had to add about 1-1/4" to the height of the shock tower to maximize uptravel.
76569
 

Alex01

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Mar 23, 2018
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Martinez, CA, USA
I have a very similar setup to yours. RE 3.5 lift, MC track bar. My front springs brand is unknown. Were you able to get down to 1.5” of bump stop with out any track bar interference? That’s with both tires stuffed at same time/ full bump?
My limiting factor is the shock body not the trackbar. I need to do a mod like strumble8 did above.

Currently I am running 3 inch of bump do to the shockbody but after I mod the front I will lower it to right around 1.5.
 

Gollywomper

TJ Enthusiast
Feb 9, 2019
337
Corning CA
Ok great. I have the 999255 shocks on now. They are a tad over 16” collapsed. So they need approx 3.5” of BS. I am limited to 3” due to track bar. I have a set off 55239 shocks as well. My RE lower arms are adjusted all the way in, so I will have to pull them off and shorten them approx 1/2” so I can pull my axle back far enough. I would like to get down to between 1-1/2” and 2” to utilize my high line fenders.
 

Gollywomper

TJ Enthusiast
Feb 9, 2019
337
Corning CA
Seems to be a pattern here. I understand that control arm length doesn't matter, just put the axle where it needs to be to clear the track bar. One thing in common in most of the track bar threads is it usually is discussed in lifts under 2.5" as at that height max up travel is very important. It doesn't seem to be much of a discussed issue at or above 3.5" lift height. That is because either people are running 3" or more bump stop to keep tires out of fenders or they just are not aware of the issue or don't care, because they flexed it on a curb at the mall and it was OK.
Most if not all lower lifts seem to clear the track bar no problem with stock length lower control arms, with stock style diff cover. I have found a few cases of guys with 3.5" or taller lifts who run high line fenders, we are looking for more up travel than a guy with stock fenders. So we run into the TB-diff cover interference issue. Lower lift rigs can set LCA to factory length or run stock LCA and clear TBs. So when a guy with a 3.5" lift who has TB diff cover contact sets the LCAs to factory length or as short as they will adjust and still has contact, what are they to do? Why doesn't it work? In reality it does not matter, just adjust them till you get what your jeep needs. Nobody is going to tell you your jeep wheel base is 1" short.
Unfortunately I am a "why" type of guy. I have been somewhat intrigued by this for some dumb reason. Why is it that a short lift will clear the track bar and the taller lift wont with the same lower control arm length. The real measurement/difference here is from frame side LCA bolt to axle center line. This length gets longer as the pinion angle is adjusted up. Taller lifts obviously need pinion angle correction to eliminate drive line vibrations. When we do that we lean the top of the axle forward. What also happens as the pinion rotates up the lower axle mounts raise in relation to axle center line, which increases the distance from the axle center line to frame side bolt. So it may be needed to adjust LCAs shorter than stock length to get to the magical axle location where everything will fit at short bump stop lengths.
My Rubicon Express lower control arms will only shorten to 15.75". I will have to cut them down to get enough adjustment.
Hopefully that make sense and helps somebody.

RH-9030-5.jpg
 
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strumble8

TJ Enthusiast
Dec 27, 2018
259
Strasburg Co.
Are you running an aftermarket diff cover on your front axle? That is where most trackbar interference comes from. I am running jks track bar
76696
4" Currie springs w/35" tires and a 1.25" body lift. Using the lower control arms to place the axle and the upper control arms to set pinion angle I am running 3" bump stop extensions. This is just enough to prevent coil bind(the max up travel) I am running a stock diff cover with a half shell diff guard.
 

strumble8

TJ Enthusiast
Dec 27, 2018
259
Strasburg Co.
Are you running an aftermarket diff cover on your front axle? That is where most trackbar interference comes from. I am running jks track barView attachment 76696 4" Currie springs w/35" tires and a 1.25" body lift. Using the lower control arms to place the axle and the upper control arms to set pinion angle I am running 3" bump stop extensions. This is just enough to prevent coil bind(the max up travel) I am running a stock diff cover with a half shell diff guard.
The photo is at full bump with springs removed. When I put the passenger side to full droop the clearances on the track bar and diff cover decrease to about 1/8".
 

Alex01

Enthusiast
Supporting Member
Ride of the Month Winner
Mar 23, 2018
2,452
Martinez, CA, USA
Seems to be a pattern here. I understand that control arm length doesn't matter, just put the axle where it needs to be to clear the track bar. One thing in common in most of the track bar threads is it usually is discussed in lifts under 2.5" as at that height max up travel is very important. It doesn't seem to be much of a discussed issue at or above 3.5" lift height. That is because either people are running 3" or more bump stop to keep tires out of fenders or they just are not aware of the issue or don't care, because they flexed it on a curb at the mall and it was OK.
Most if not all lower lifts seem to clear the track bar no problem with stock length lower control arms, with stock style diff cover. I have found a few cases of guys with 3.5" or taller lifts who run high line fenders, we are looking for more up travel than a guy with stock fenders. So we run into the TB-diff cover interference issue. Lower lift rigs can set LCA to factory length or run stock LCA and clear TBs. So when a guy with a 3.5" lift who has TB diff cover contact sets the LCAs to factory length or as short as they will adjust and still has contact, what are they to do? Why doesn't it work? In reality it does not matter, just adjust them till you get what your jeep needs. Nobody is going to tell you your jeep wheel base is 1" short.
Unfortunately I am a "why" type of guy. I have been somewhat intrigued by this for some dumb reason. Why is it that a short lift will clear the track bar and the taller lift wont with the same lower control arm length. The real measurement/difference here is from frame side LCA bolt to axle center line. This length gets longer as the pinion angle is adjusted up. Taller lifts obviously need pinion angle correction to eliminate drive line vibrations. When we do that we lean the top of the axle forward. What also happens as the pinion rotates up the lower axle mounts raise in relation to axle center line, which increases the distance from the axle center line to frame side bolt. So it may be needed to adjust LCAs shorter than stock length to get to the magical axle location where everything will fit at short bump stop lengths.
My Rubicon Express lower control arms will only shorten to 15.75". I will have to cut them down to get enough adjustment.
Hopefully that make sense and helps somebody.

View attachment 76679
Please update on how much you cut off the lowers and the results. Also, if you need to trim a bit off the uppers. I will be following suit in the near future.

Edit: sorry @strumble8 replied to the wrong post.
 
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