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Still have Bumpsteer

5K views 35 replies 6 participants last post by  kjeeper10 
#1 ·
I've got an 07 JKUR.
4" Currie Lift
AEV Geo Correction brackets.
Currie Front adjustable track bar
Currie Track bar bracket Front and Rear
Synergy Drag Link Flip
Etc.

Fought DW for a month or so and finally resolved that through ball joints etc.

Here's some pictures of my front end. Any suggestions are welcome.



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#2 ·
And when I say bump steer I mean it. The geo correction brackets helped a lot along with the drag link flip. But I'm still getting wandering on uneven roads, dips, bumps, things of that sort jerk the wheel around if I'm not holding tight.

I have the toe in at 3/16 on 35 bfg at's
Castor is in the ball park I think. I have been adjusting a lot recently with the upper control arms and track bar trying to get everything true and center.
 
#4 ·
The Currie is a solid lift kit, but root of your challenge is that you selected a fairly large lift, at least for a JK and a lift kit that is not optimized for handling and ride. Then you added some parts to correct some of the deficiencies of the design. This improved the ride and handling but may not enough for your preferences. It's a complex geometry problem needs to be addressed when the lift kit is designed. Their party products may improve the geometry, but it is highly unlikely they will be the best match.

Part of the steering wander may be due to your tires tracking unevenness and small ruts on the road. The steering may not get to point you expect it to, even a stock Jeep has some Bump/Roll Steer.
 
#9 ·
The Currie is a solid lift kit, but root of your challenge is that you selected a fairly large lift, at least for a JK and a lift kit that is not optimized for handling and ride. Then you added some parts to correct some of the deficiencies of the design. This improved the ride and handling but may not enough for your preferences. It's a complex geometry problem needs to be addressed when the lift kit is designed. Their party products may improve the geometry, but it is highly unlikely they will be the best match.

Part of the steering wander may be due to your tires tracking unevenness and small ruts on the road. The steering may not get to point you expect it to, even a stock Jeep has some Bump/Roll Steer.
I am just trying to be a perfectionist I guess. I understand the risk I took when going for a lift of that size, that's why I chose Currie. I guess I need to sit down with my buddies and fabricate a better bracket for the track arm mount.
 
#5 · (Edited)
You can't go by looking at the Steering angles. From mounting point to mounting point if you were to draw a line.

My 2 door is pretty complete up front. Never going to be perfect.

Caster is in the ballpark you think ?
The brackets already fix caster. Are you sure you don't have enough or too much adjusting arms ?
 
#10 ·
You can't go by looking at the Steering angles. From mounting point to mounting point if you were to draw a line.

My 2 door is pretty complete up front. Never going to be perfect.

Caster is in the ballpark you think ?
The brackets already fix caster. Are you sure you don't have enough or too much adjusting arms ?
Well I had left CA's where the were from the alignment shop when I recently installed the AEV geo brackets. Then I realized I may have a little too much caster because my springs were bending backwards under flex. So I have been dialing it out little by little.


Good post Spin

OP... How high is the rear TB bracket? Handling is greatly benefited w/ a higher rear roll center.
(Understeer)
Rear track bar bracket matches the front, although I'm using a RE trackbar in the back.
 
#7 ·
I have 0 bumpster at 4" lift with the TF monster trackbar and AEV draglink flip /SS relocation kit. My trackbar and draglink are parallel. Due to the weird bends in trackbars the only way to determine the trackbar angle is to draw a line as in the photo above.. Both should be parallel, if not, you have bumpsteer.
 
#11 ·
Are you positive there's no play where the knuckle was drilled ? Did you ream or use a adapter ?

Assuming your front track bar bracket is 3" to match the flip... The angles should be fine.
Plenty of people running 4-5" lift and steering correction, all TB brackets I know if raise 3"
 
#12 ·
Are you positive there's no play where the knuckle was drilled ? Did you ream or use a adapter ?

Assuming your front track bar bracket is 3" to match the flip... The angles should be fine.
Plenty of people running 4-5" lift and steering correction, all TB brackets I know if raise 3"
I used a drill bit and the adapter and there is no slop.
Although I could barely get the stud down far enough to get the cotter pin through. I cant remember the torque spec but I had to go beyond it to get the hole uncovered by the knuckle.

Take a closer look at the picture and you'll see what I'm talking about.
 
#13 ·
Needs to be seated more.

A lot of folks had issues drilling the knuckle. SYnergy has changed their instructions like 3 times already.

Looking at the lines in that pic. with the TRE seated properly that angle would better match up with the track bar.
I'm no geometry wiz, but A 1/4" over the length of the drag link is magnified a good amount.

Pull that end and measure the hole. I'm pretty sure it's going to be small. What bit did you use ?

Call or go to Synergy's site and request the smaller adapter, assuming you received the 7/8 which doesn't always work.

I just installed a synergy drag link. The jeep already had AEV's adapter/flip. The TRE would not fit at all. She bought the 13/16 adapter. It dropped right in and TRE fit perfect.
 
#18 ·
Just went for a test drive and it is almost 100% better. Still a little feedback in the wheel but it seems pretty minor. Now I'll dial in the caster to be positive everything is on its mark and I'll be a happy camper.
 
#20 ·
With the tie rod in the way I could only tighten it down with a wrench originally. Plus I followed the torque spec.

Today when I pulled the cotter pin out there was hardly any network left on the nut. I then tightend it down using a box end wrench and use my feet as leverage and tightened it down as hard as I could. I'm afraid to go any farther due to the original torque spec.
 
#23 ·
I have the RE super flex 3.5" lift but its closer to 4.5" with the acos spacers up front and 3/4 spacer in the rear.

After installing the Teraflex HD flip kit I still had a slight bump steer. I had the toe adjusted to 18 on both sides and the bump steer went away.
 
#24 ·
I have the RE super flex 3.5" lift but its closer to 4.5" with the acos spacers up front and 3/4 spacer in the rear.

After installing the Teraflex HD flip kit I still had a slight bump steer. I had the toe adjusted to 18 on both sides and the bump steer went away.
Do you mean "Bump Steer" or the wheels would follow uneven groves of the road and such.

I'm at 3/16 toed in right now, but I'm getting 35x12.5x15 General Grabber AT2's tomorrow and will be going back to 1/16. Perhaps experimenting toeing out a hair just to see how it works on/off road.

I'll post pictures of the new rims and tires along with the rest of my products that have broken the piggy bank.
 
#30 ·
I've experimented with toe. Never out. 1/16, 1/8 and 3/8 in. Can't say I felt any difference. I think a lot depends on tire size. Also heavier HD components. It all depends on your setup, for example, I've seen jeeps run all different toe specs. One setting may work for one but not the other.
 
#31 ·
Just went for a test drive, highway and trail, with the toe out 1/16 (could have been dead even it was so close). Major improvement, steering as expected took much less effort, a hint of oversteer (which I prefer), and I did not notice any wandering what so ever.

So going from toe in 3/16 - 1/8 felt good on the straights but that's about all. I skipped 1/16 and went to my current setting of 0 - 1/16 toe out and I am very happy.

I'm running a Currie 4" lift.
AEV Geo Correction Brackets
35 x 12.50 x 15 Grabber AT2s
32 psi

Side note: Going from a Load D to a Load C tire along with the added sidewall from my new 15" wheels is the best decision I've made on an upgrade, the ride went from tractor to Cadillac.
 
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