Bump steer after 4.5" Rubicon Express SuperFlex

08GumbyJKU

08GumbyJKU

New member
Had the 4" rancho with jks track bar and factory drag link. Now that I have all rubicon express it's got way more response through the steering and every little bump or dip the wheel turns. Not what I was expecting from this lift. My track bar drag link angles look pretty close to perfect as they can get.. What gives? Everything's torqued and tightened down, wheels straight. What am I missing? It's got the rubicon express track bar drop, and the chromoly drag link and adjustable track bar from RE.
E9BCB3DC-947F-4B46-AC70-CDFC82E02AEE_zpszpkwagbw.jpg
 
Cant tell for sure but, is it safe to assume your drag link is flipped? At least, it sure looks like it as the spread between your track bar and drag link is significant. Removing your track bar frame bracket and installing a relocation bracket at the axle will help mitigate what you're feeling now.
 
I am no expert by any means but I just went through some symptoms similar to yours and I think we all explain or describe what we feel differently. For me it was Castor. you might what to check to make sure you have enough, even 1 degree can make a difference.
 
It's just very odd to me. I took this lift off a '13 JKU before it was installed on mine, and the steering was tight and didn't shimmy/bump steer. Just quite confused because the quality and engineering of this lift surpasses Rancho, and my thoughts were it would be better in every aspect. (which is it, handles like it did stock, just the steering is not how it should be)
 
It is going to get re-aligned tomorrow since all my usual shops were booked yesterday. Hopefully that'll fix it.
 
Same things I was thinking also, caster and ditch the frame side drop bracket. Look into a raised axle side bracket. Not sure if evo sells just the bracket. Also that's a lot if leverage on your frame bracket. Kind of like a breaker bar.
 
wayoflife said:
Cant tell for sure but, is it safe to assume your drag link is flipped? At least, it sure looks like it as the spread between your track bar and drag link is significant. Removing your track bar frame bracket and installing a relocation bracket at the axle will help mitigate what you're feeling now.
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I was thinking this, or he needs to add a drop pitman arm. (As they should be installed together )

I would remove the bracket and take it for a spin
 
08GumbyJKU said:
It's just very odd to me. I took this lift off a '13 JKU before it was installed on mine, and the steering was tight and didn't shimmy/bump steer.
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Well hang on a sec, are you having shimming issues or are you having what feels like bump steer or both? Better yet, rather than give what you're feeling a name, why don't you explain exactly what is happening and under what conditions.

Just quite confused because the quality and engineering of this lift surpasses Rancho and my thoughts were it would be better in every aspect.
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Really? And exactly how did you come to this conclusion?

...(which is it, handles like it did stock, just the steering is not how it should be)
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Don't get me wrong but, if the steering is not how it should be, it doesn't sound like it handles anything like your Jeep did when it was stock.
 
piginajeep said:
I was thinking this, or he needs to add a drop pitman arm. (As they should be installed together )

I would remove the bracket and take it for a spin
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I asked him if it's flipped but he didn't answer me. Looking at the pic, the track bar and drag link look pretty parallel so, I'm assuming it's flipped.
 
wayoflife said:
I asked him if it's flipped but he didn't answer me. Looking at the pic, the track bar and drag link look pretty parallel so, I'm assuming it's flipped.
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But if it's flipped with a drop bracket off the frame, he's really fucked for geometry.

Re sells the lift kits with just a drop bracket, (the flip is a paid upgrade). Depending who installed it, I guess they could have installed both
 
Yep the drag link flipped, had to ream out the top of the knuckle. Per the instructions. When I traveling at speed I can feel the bump and dips through the steering wheel, and it slightly turns(no violently, just a little.) the jeep tracks straight and the wheel does not wobble back and forth just turns slightly in the direction of the dip(right tire wheel turns right; left tire wheel turns left). I am no engineer, I just swapped the kit over exactly how it was installed on the jeep i took it off of. I appreciate all the help, just confused on what would cause this when the other jeep did not have this issue.
 
08GumbyJKU said:
Yep the drag link flipped, had to ream out the top of the knuckle. Per the instructions. When I traveling at speed I can feel the bump and dips through the steering wheel, and it slightly turns(no violently, just a little.) the jeep tracks straight and the wheel does not wobble back and forth just turns slightly in the direction of the dip(right tire wheel turns right; left tire wheel turns left). I am no engineer, I just swapped the kit over exactly how it was installed on the jeep i took it off of. I appreciate all the help, just confused on what would cause this when the other jeep did not have this issue.
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Did the instructions say to leave the frame side bracket on ?
 
Did you remove our control arm correction brackets, by chance? :thinking:
I think you mentioned that in another thread, start there... just because a kit costs more on paper doesn't always mean better. :beer:
 
I'll throw my 2 pesos in.

You need to remove the frame side track bar bracket and install an axle side raised TB bracket to go along with your drag link flip.
This returns your Roll Center back to nearly factory height (which you want). Right now, the 2 bars are not parallel.

Next is caster. I can see you have the off-set washers on your lower control arm brackets.
Have the alignment shop (or do it yourself) set your caster to as close to +4.2 degrees, but watch your drive shaft angle, you might have to compromise a little caster for the drive shaft.

All this is explained in the WOL write up; http://wayalife.com/showthread.php?3861-Basic-Do-it-Yourself-Jeep-JK-Wrangler-Front-End-Alignment

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