Why do I have bump steer?

[rock-rod]

I drive a '22 4XE JLUR and installed a mopar (4xe specific) lift along teraflex 1 inch spacers in the front. Ive heard nothing but rave reviews AEV geo-correction brackets so I installed those as well. I also have a steersmarts adjustable track bar and their steering box/upper track bar reinforcement bracket. After installing these parts, I now have crazy bumpsteer. It's very noticeable on the highway whenever larger bumps are hit. Why is this? I've checked and rechecked all of the components to ensure everything is tight. Any ideas?

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[jadmt]

you probably have much more lift than the 2" lift with the mopar lift and add 1" on top of that for the spacers and you could be 4-4.5" lift easily....so yes bumpsteer happens..geo brackets do not stop bump steer they just increase caster and smooth out the ride...you will need to look at a high steer kit to address bumpsteer if your lift is too high. what are these measurements?

 

[Roky]

I drive a '22 4XE JLUR and installed a mopar (4xe specific) lift along teraflex 1 inch spacers in the front. Ive heard nothing but rave reviews AEV geo-correction brackets so I installed those as well. I also have a steersmarts adjustable track bar and their steering box/upper track bar reinforcement bracket. After installing these parts, I now have crazy bumpsteer. It's very noticeable on the highway whenever larger bumps are hit. Why is this? I've checked and rechecked all of the components to ensure everything is tight. Any ideas?

The biggest cause of bump steer is the drag link and the track bar not running parallel with each other…sometimes if the axle isn’t centered it will be out of parallel with the drag link…. I’d check this first….

 

[rock-rod]

I measured the shock length from eye to eye with the jeep on the ground (full weight on suspension) and got 23.5 inches, so just a little over three inches of lift which is what I would expect. Is that enough lift to warrant a track bar relocation? Could having too much caster cause bump steer? One thing is for sure, there is no hint of DW, but at the same time there's a lot of feedback through the steering wheel (which is think is a result of the large amount of caster and the steering box/sector shaft bearing brace). It's not a fun experience cruising at 75mph and to hit a bump that causes the front end to feel floaty and disconnected. If I hold the wheel the jeep will steer right/left as the suspension moves up and down.

you probably have much more lift than the 2" lift with the mopar lift and add 1" on top of that for the spacers and you could be 4-4.5" lift easily....so yes bumpsteer happens..geo brackets do not stop bump steer they just increase caster and smooth out the ride...you will need to look at a high steer kit to address bumpsteer if your lift is too high. what are these measurements?

 

[Roky]

I drive a '22 4XE JLUR and installed a mopar (4xe specific) lift along teraflex 1 inch spacers in the front. Ive heard nothing but rave reviews AEV geo-correction brackets so I installed those as well. I also have a steersmarts adjustable track bar and their steering box/upper track bar reinforcement bracket. After installing these parts, I now have crazy bumpsteer. It's very noticeable on the highway whenever larger bumps are hit. Why is this? I've checked and rechecked all of the components to ensure everything is tight. Any ideas?

Did you get an alignment after lift installed? Would like to see caster number and toe…. If toe out to much that also can contribute to bump steer…. Depending on your tire size( 35s / 37s) I like to set toe at 1/16 th toe in…

 

[rock-rod]

Did you get an alignment after lift installed? Would like to see caster number and toe…. If toe out to much that also can contribute to bump steer…. Depending on your tire size( 35s / 37s) I like to set toe at 1/16 th toe in…

I did have an alignment done but didnt get the numbers :/ Funny thing, the issue became worse after the alignment was done.

 

[rock-rod]

The biggest cause of bump steer is the drag link and the track bar not running parallel with each other…sometimes if the axle isn’t centered it will be out of parallel with the drag link…. I’d check this first….

I checked these and the track bar and drag link are both on the exact same plane. I also checked the side/side alignment of the axle and it's center exactly under the jeep at ride height.

 

[Deleted User 38384]

I checked these and the track bar and drag link are both on the exact same plane. I also checked the side/side alignment of the axle and it's center exactly under the jeep at ride height.

Probably a dumb question, are you still running the factory steering stabilizer?

If you've ever taken your Jeep off-roading, you might want to look and make sure that you haven't dented your steering stabilizer. I replaced mine recently because it had almost no hydraulic fluid left in it after I hit it on a few rocks last year. Went and got in over the axle kit from synergy for like a hundred bucks, and ordered a skyjacker 9000 series steering stabilizer, and now my Jeep is like butter on the roads.

Btw, I installed the skyjacker 1.5 in lift kit, and gained about 2 in out of it. I had put the Mopar extended front lower control arms on there which corrected the caster angle and brought it back into spec.

Upgrading the steering stabilizer definitely made a big difference for me. I used to feel like I was bottoming out on every bump on the road, including the tiny little divot I would go over entering my community I live in. After the lift the ride still wasn't fixed, but after the steering stabilizer upgrade and replacement, problem solved! Smooth and comfortable ride!

 

[roaniecowpony]

As you lift the suspension, the angle of the control arms gets steeper. When you hit a bump and that wheel travels upward, it will move in an arc. In the front, the axle side that moves upward, also moves forward. In the rear, the axle side that moves upward, moves rearward. That's why geometry correction brackets were created.

 

[Roky]

I did have an alignment done but didnt get the numbers :/ Funny thing, the issue became worse after the alignment was done.

With the Mopar lift, the only thing they could change is Toe, and straighten the steering wheel…with fixed control arms there’s no way they can adjust caster.

Unfortunately without seeing caster and toe readings, it’s hard to determine if they are contributing to the issues….You can check toe and caster yourself, just bring up some YouTube videos on it… it’s not hard to do….I don’t want to send you down the wrong path on a fix that’s gonna cost more money, and have it be something simple…….

 

[Willys41]

I drive a '22 4XE JLUR and installed a mopar (4xe specific) lift along teraflex 1 inch spacers in the front. Ive heard nothing but rave reviews AEV geo-correction brackets so I installed those as well. I also have a steersmarts adjustable track bar and their steering box/upper track bar reinforcement bracket. After installing these parts, I now have crazy bumpsteer. It's very noticeable on the highway whenever larger bumps are hit. Why is this? I've checked and rechecked all of the components to ensure everything is tight. Any ideas?

I had the same problem.
4.5in. lift 37 and bead locks all new high end components front and rear.
For a year I was tying to solve the problem.
My local 4x4 shop told me they set the toe 0 to 1/8 out.
I resisted for a year and then read the Metal Cloak also recommend toe out so I decided to give it a try.
After setting my toe out 1/8 problem solved. 95% of the shake and shimmy at speed when hitting bumps is gone.
Buy yourself a set of toe adjustment bars and readjust the toe and see what happens.
You may solve your problem.

https://www.amazon.com/Fuzqq-Alignm...e5d-4cac-8b44-940972c530a5&pd_rd_i=B0CMCRD2J5

 

[rock-rod]

I had the same problem.
4.5in. lift 37 and bead locks all new high end components front and rear.
For a year I was tying to solve the problem.
My local 4x4 shop told me they set the toe 0 to 1/8 out.
I resisted for a year and then read the Metal Cloak also recommend toe out so I decided to give it a try.
After setting my toe out 1/8 problem solved. 95% of the shake and shimmy at speed when hitting bumps is gone.
Buy yourself a set of toe adjustment bars and readjust the toe and see what happens.
You may solve your problem.

https://www.amazon.com/Fuzqq-Alignment-Automotive-Provides-Measurements/dp/B0CMCRD2J5/ref=pd_ci_mcx_mh_mcx_views_0_title?pd_rd_w=aM7lN&content-id=amzn1.sym.bb21fc54-1dd8-448e-92bb-2ddce187f4ac:amzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&pf_rd_p=bb21fc54-1dd8-448e-92bb-2ddce187f4ac&pf_rd_r=1ZZ1AKRVVN63TPM2VZ2C&pd_rd_wg=Y5swD&pd_rd_r=4de29618-fe5d-4cac-8b44-940972c530a5&pd_rd_i=B0CMCRD2J5

Thanks for this information. I have a toe alignment kit on order and will check it once the kit arrives.

 

[GaryToo]

I have a very slight amount of bump steer, not a wobble or a shimmy which is not bump steer . Im only at 3" lift but at good sized dips in the highway at speed when the suspension cycles a lot I can feel a slight rotation in the steering wheel . Right now I only added the Currie drag link . I expect it to be gone when I get around to installing the rest of my Currie high steer kit leveling track and drag link by 2.5".

 

[rock-rod]

I picked up a digital degree finder and took some measurements. Garage floor slants down at a 7.3 degree angle (jeep is parked facing 'up-hill' in the garage). I get 8.3 degrees on the machine flats of the front axle (where the diff case spreader holes are located). This makes for a difference of 1 degree between the garage floor slope and the housing angle. If the built in caster is 6 degrees positive with the flats at zero, then I get 7 degrees positive caster with the current set up (mopar 3in lift with 1 inch spacer, AEV geo-correction brackets set to the middle caster position which is recommended for 2.5 to 3in lifts, and the mopar extended length LCAs installed). Does that sound right? It seems like the caster would be more like 8-10 degrees positive with the AEV brackets and longer mopar LCAs, right? Also - I did confirm that I have the required minimum distance that AEV specs for use of their geo-correction brackets (minumum of 5 inches from bottom of frame to spring perch, I have 5.5 inches).

I'm thinking of swapping the extended LCAs for a set of stock-length LCAs and see where I land with caster. From what I gather, caster for a 4 door JL should be around 5 to 5.5?

 

[jadmt]

yea I did not realize you were using the longer control arms with the geo brackets...use one or the other.

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