Can you 100% eliminate steering shimmy?

Can you 100% eliminate steering shimmy?


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Jeep&dogs

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So does anyone feel that you can 100% eliminate steering wheel shimmy after hitting a bump on a solid axel vehicle? I’m not talking full on death wobble I’m talking about an oscillating feeling in the wheel for a second or so after hitting a decent size irregularity in the road. My JLUR with a 2” dynatrac lift, 35’s, full set of Clayton arms, synergy front and rear track bars, synergy sector shaft brace, latest cast iron steering gear,and Fox ATS stabilizer drives 99.9% perfect. BUT I have one road in particular I travel 2-3 times a week and one bump in particular that will cause a shimmy in the wheel for a split second and then it’s gone. If I hit it at 55-60 you hardly notice it, at 45 it is more pronounced.

I have played around with tire pressure and at 31.5 it’s probably the best, also I have played with caster, 7, 6.8, 6.5, 6.3, and 6.5 it the sweet spot for caster. My next thing was going to be swapping out to RPM steering but I’m beginning to wonder if I am just chasing my tail and I should call it a day. Like I said 99.9% of the time the thing drives absolutely fantastic and is probably the best handling Jeep I have owned and I am coming from a pretty well built 04 Lj.
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limeade

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I think you may start chasing your tail with this. I have a similar setup as you (RK suspension and all Synergy steering, but haven't done the steering box upgrade yet) and I may get some slight bump steer every once in a blue moon, similar to you. It doesn't even bother me as it not's consistent issue, which would lead me to believe something was wrong.

I think what you're experiencing is bump steer and could just be a product of the Wrangler's steering/supension design and a solid front axle. About the only things you haven't changed out (from what you listed) are the ball joints and axle front upper control arm bushings. I have the Dana HD ball joints and Rock Jock upper control arm bushing kit to install in mine in a few weeks. After I get those in, I'll know if the steering "is what it is" or it can be improved upon. But overall, I am happy with how my JL steers and handles.
 

Zotch

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I have 33's (32 psi), steering box replacement, Falcon 2.1 shocks, Teraflex track bar and Mopar LCA's.

It is MUCH better over bumps than it was before. At this point I am happy enough.
 

Tru-Trac

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Same experience here. 2” Dynatrac, 35, track bars and LCAs. Factory steering box (2019). I only notice a slight shimmy once in a while just like the OP. I’m trying to decide if it’s worth replacing the steering box or not.
 
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Jeep&dogs

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I think you may start chasing your tail with this. I have a similar setup as you (RK suspension and all Synergy steering, but haven't done the steering box upgrade yet) and I may get some slight bump steer every once in a blue moon, similar to you. It doesn't even bother me as it not's consistent issue, which would lead me to believe something was wrong.

I think what you're experiencing is bump steer and could just be a product of the Wrangler's steering/supension design and a solid front axle. About the only things you haven't changed out (from what you listed) are the ball joints and axle front upper control arm bushings. I have the Dana HD ball joints and Rock Jock upper control arm bushing kit to install in mine in a few weeks. After I get those in, I'll know if the steering "is what it is" or it can be improved upon. But overall, I am happy with how my JL steers and handles.
I actually do quite a bit of race car fabrication and honestly the Jeep really doesn’t have any bump steer. I have checked this on an alignment rack and you can actually bounce the suspension quite a bit and there is no toe change or movement of the wheel. I have also been looking at the Rock Jock upper bushings. The Jeep only has 8k on it and the ball joints check out fine. But with the stock steering you can flex that pretty much by hand under the Jeep. That’s why I was looking at the RPM and steer smart set ups. I don’t know, some days I’m thinking I should just leave well enough alone and call it a day , and others I think I could get that last .01 out of it! 🧐
 
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Jeep&dogs

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The really annoying part about this is it seems like it is very sensitive to any type of change. I played around with the toe a little today and 1/16-1/8 actually makes a noticeable difference. Bad thing is less toe made it slightly more stable going over the section of road, but it seems like it makes it wander a little more and fight to center.
 

Leisure Freak

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Maybe because I have been driving old cars for too long but I haven't noticed any wobble, shudder, or anything to make me think something wasn't right with the steering. Even after 20 miles of washboard, although slower driving. Completely stock 2 door sport with C rated 265/70/17 K02s running at 36 psi on stock steel rims. Mine is a 2019 with late April build bought Jan 2020 so they had already done any recall work.
 

MattT69

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I just experienced my first shudder yesterday and again today several times at low speed. What causes this and what are the fixes???

For background: I have a 2018 JLR with 12K miles
I have the Duratrac Euro 2" lift +1/2 teraflex load lever (so 2.5": total). I added the teraflex-sport front LCAs. Also run 35s on stock Rubi wheels with teraflex wheel spacers.

Edit Update:
Added an adjustable trackbar from JKS and so far (1 week) when I go over the same potholes and even larger ones on the freeways the wobble is gone! Steering feel slightly firmer which feels good. Tracks straight. More updates to come as things change.
 
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TxJeepers

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I think you may start chasing your tail with this. I have a similar setup as you (RK suspension and all Synergy steering, but haven't done the steering box upgrade yet) and I may get some slight bump steer every once in a blue moon, similar to you. It doesn't even bother me as it not's consistent issue, which would lead me to believe something was wrong.

I think what you're experiencing is bump steer and could just be a product of the Wrangler's steering/supension design and a solid front axle. About the only things you haven't changed out (from what you listed) are the ball joints and axle front upper control arm bushings. I have the Dana HD ball joints and Rock Jock upper control arm bushing kit to install in mine in a few weeks. After I get those in, I'll know if the steering "is what it is" or it can be improved upon. But overall, I am happy with how my JL steers and handles.
Did you replace front upper bushings? What was result?
 

limeade

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Did you replace front upper bushings? What was result?
Yes, they were installed at the end of December. The steering was already good and the stock upper axle bushings were in good shape. This was more of a preventative measure as I wanted to get rid of the last remaining stock rubber bushings as they can wear prematurely with off roading. Once the stock clevite rubber bushings wear or the bonded inner sleeve rips/tears from the rubber bushing, you can get a shimmy. I never did have a shimmy like some, but if you do and you have replaced all of the other known culprits, this may be the one to solve it.

I had this problem in my 04 TJ Rubicon and the Rock Jock UCA axle bushings were a huge help in eliminating the shimmy.

Unfortunately, I also installed the Dana HD ball joints right afterwards and didn't do a test drive with only the UCA bushings installed. My stock ball joints were pretty loose as compared to the new Dana's. Both of these upgrades resulted in a better feel in the steering and handling. The steering was slightly more responsive, with a more solid feel.

After those parts were installed, I still wanted to get the steering TSB done. I'd gotten used to it, but I was having to make a lot of small steering adjustments at higher speeds. I got the TSB done in mid-January and found it had eliminated the need to make all of those tiny steering inputs.
 

MARSHMELLA

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I have a 2021 JLUR lifted on 37s. I’ve never felt any kind of shimmy or steering movement over any bumps.
 

laroo

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I've been following all of the shimmy threads, figured this was a good place to add my experience. I have a JLU Sport, but added Rubicon suspension last year, and had no problems. But the suspension gave me a noticeable rake, and I found a pair of front Rubi springs with higher numbers for cheap. Installed those to level the Jeep a month later. That's when my shimmy appeared, it always happens in the same location on the road, front left tire hits the bump first, less than a second, small-amplitude oscillation of steering wheel.

After new wheel installation recently, the shop aired the tires back up to 37 or so, from my normal 34. I hit the bump at a slightly different angle while switching lanes, and the shimmy was much bigger, and lasted a couple of seconds this time. It felt really close to getting into death wobble. I've seen videos, and this certainly wasn't full-on death wobble, but I could see this Jeep getting there in the right conditions. First thing I did was take some air out of the tires (Jeep showed tires at 39-40 on this hot day), then tried to hit the bump at the same angle a few times. It was back to the small shimmy, I couldn't recreate the bigger shimmy. I'm hoping if I keep my tire pressure lower, then I'll be ok.

I did check torque everywhere, except control arms. My next thing to do is loosen all control arm bolts, then retorque. Not looking forward to getting the LCA back to 190, that's why I've been stalling.

Something I did with the Rubicon suspension started my shimmy, and I really have no idea what to do after retorquing the control arms. I'm only running 285/70/17 tires, so it's basically stock Rubi geometry. Caster is 5.7, which seems high from what I've seen here for stock Rubicons. I've considered installing the Mopar lift LCAs, but the Jeep tracks pretty straight as is. For now, I'm just living with it, but if I experience the bigger shimmy again, I'll definitely do more.
 

TxJeepers

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Welcome to the club. You describe it almost exactly as mine. I’ve got almost everything on my front end suspension and steering replaced trying to figure out what it is. Looking forward to @Jeep&dogs update this weekend.
 
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Jeep&dogs

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Welcome to the club. You describe it almost exactly as mine. I’ve got almost everything on my front end suspension and steering replaced trying to figure out what it is. Looking forward to @Jeep&dogs update this weekend.
Failure, probably pulling everything off and existing stage left. I might put it back to stock height and if it drives OK call it a day and try to off some of the parts without taking a bath on them too bad. If it still does it five gallons of gas and a highway flare in the middle of the Chrysler service bay I bought it at.
 

Mikepa

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This winter I started noticing and troubleshooting the same shimmy on my ‘18 JLUR. Only noticeable at speeds under highway, say under 50mph. Definitely not death wobble or bump steer. 37 Toyo MTs on 17” Icons., 2.5” MC Gamechanger with HD steering and updated stock stabilizer and aluminum steering box. Little to no problems with tracking straight. Recent overdue tire rotation eliminated slight pull to right but shimmy still there.

Having broken 20K miles I suspected OE ball joints but they check out okay. All adjustable arms and bars tight. Only thing that changed was cold temps and subsequent tire pressure drop from my standard 28 to as low as 25 when temps below 30 degrees.

Considering an adjustable stabilizer to get that shimmy out, I brought rig in for third free oil change. Told dealer not to rotate tire as just were done. Left dealer and noticed shimmy SEEMS to have disappeared. What changed? They filled tires up to 33 lbs. Now wondering if the D rated MTs could be flexing at lower speeds causing the shimmy. Dropped pressure to 30 and will continue to monitor. Could it be this simple?

6ABCEE17-1775-45DC-8F86-2EB551D43F85.jpeg
 
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