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Bump Steer Help!

16K views 39 replies 14 participants last post by  Pressurized  
#1 ·
Hello all, just looking for a little help with what I believe is bump steer. Newbie to Jeeps so any input much appreciated! 2017 Sahara Unlimited. Bought stock 2 months ago. Added 2 1/2 RC Suspension Lift, 1.5" wheel spacers. 33" tires on 17s. Drove beautiful before the lift and spacers, after lift noticed what I believe is bump steer, off road shop doing all my work added a HD adjustable track bar, still issues. Shop then added relocation bracket for track bar and now it's even worse! Slightest bump or dip and it feels like I'm going to lose control. Where do I start?
 
#8 ·
Ditch the shop that recommended the track bar height or drop bracket without a draglink flip, they suck! RC was not your best decision. Return to stock track bar geometry configuration and work on restoring factory caster or higher caster settings. Higher quality steering linkage will help. Also check tire pressure and expect pressure from larger tires to be lower than factory specifications. Good Luck!
 
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#11 ·
Like what Rob50lx said, stay away from a shop that would sell you a front track bar relocation bracket for a 2.5" lift without the accompanying draglink flip. That will actually CAUSE bumpsteer.
Likely you didn't actually have bumpsteer until they did that.
Bumpsteer is when suspension travel up and down causes steering inputs left and right. It happens when the trackbar and draglink are not parallel. The moment you install a raised trackbar bracket without installing something to match the new angle of the trackbar for the draglink you will have bumpsteer.
Odds are the original issue was a cheap lift that didn't include caster correction. Caster is reduced when you lift, and not enough caster causes instability. Caster is what makes the Jeep want to drive straight. Not enough caster will result in a Jeep that doesn't want to drive straight and hitting bumps will easily veer it off course.
Caster is easy to correct. You can use longer lower front control arms, adjustable lower front control arms, or geometry brackets. I would recommend geometry brackets, especially if the primary focus is on making it drive well. Geometry brackets will correct caster and the correct the control arm angle which allows the front suspension to work better and do its job of absorbing bumps better.
Rancho make a great set of geometry brackets. But other brands like JKS, MetalClaok, and AEV are options. But the Rancho brackets are one piece (which makes installation easier) and stout.

I would have the shop remove that raised trackbar bracket (or remove it yourself), and if you don't already have something to correct caster I would add caster correction. The aftermarket trackbar won't hurt, but a raised front trackbar bar bracket will.
You may want to find a shop that knows what they are doing.
 
#24 ·
i would imagine the RC kit especially with such a small lift would have decent geometry. You could screw around swapping parts and just waste time and money. but with the design software used in todays kits it should work well. take it to an alignment and chassis shop and get a four wheel alignment. give them a rundown of the issues they should be able to put it right. anytime you lift anything you need to have it dialed in .some of the best shops are the semi truck shops where they need to know there business.
 
#25 ·
Sadly, it doesn't work like that... RC leaves off the parts needed to make it work right. And an alignment shop cannot adjust what isn't adjustable and nothing in the Smaller RC lifts are adjustable. It's one of the reasons why they have a bad reputation.
 
#26 ·
For what it's worth, I had the same symptoms you described when I bought my JK lifted 2.5". Following the guidance of @GuzziMoto I installed the Rancho Geometry Brackets, which allowed correction of the caster. Got the caster up to around 5 degrees and the vague steering (bump steer) disappeared. Keep in mind I didn't have the trackbar relocation bracket yours now has so as indicated by others, that may need to be removed also, but that advise is better left to the others commenting here.
 
#31 ·
Trying to get the drag link and track bar in the same arc path is the goal. The circle of swing being the same or different effects the bump steer. I'm at 4.5", or a hair higher, and flipped the drag link at the axle side. As well as raising the track bar mount that side as well. Then adjusting arm lengths gets them in a similar arc. Think of it as two circles that need to have the same swing. They don't need to end at the same spot. Like a circle centered inside another circle an arm going around the center pivot would pass through both circles simultaneously and in the same arc. So trying to get the drag link and track bar at the frame side to be as close as possible to the same pivot spot laterally. Look at the pitman arm pivot and the track bar pivot from the front of the vehicle dead on front to back axis. The two should appear to pivot from a fairly close axis from front to back. Height difference is more important. If the axis is a hair off not as big of a deal cause the pitman arm moves and the track bar doesn't and making them even is chasing your tail. Change the heights of stuff at the axle side to keep things in the same arm though their travel.
 
#40 ·
The common value shocks are Rancho 5000X and Rancho 9000XL as well as Bilstein 5100 series. A little more money and you are in to Fox 2.0's... Teraflex 9550's are ok, my daughter has them. But I would probably choose the Rancho 5000X for good performance and very economical.