Beating a deathwobble horse

[Jcichy71]

Tons of death wobble info out there… just want to see if anyone with more experience can give me insight.

2004 Rubicon, bought it bone stock a year ago. Added a winch and had a couple worn out tie rods so I added a 1.75” spring spacer and shocks to level front end, new track bar and swapped out for ZJ steering with FOX stabilizer and that was great.

Recently noticed some clunking in the front end so lifted it and had some play in D/S front tire, figured it was a wheel bearing so I replaced the unit bearing and put it back together. Still clunking, still had play.

From there I assumed ball joints and so earlier this week I decided to do all 4 ball joints, I did both axle ujoints since I was in that far already, and I removed the factory springs and 1.75” spacers and replaced with 2” springs to further level out jeep (sits perfect now). Rechecked my alignment, slight toe in between an 1/8 and 1/16 “ (tapemeasure alignment). So at this point, everything under the front end is new pretty much.

This morning on my way to work I hit a pothole on the highway doing somewhere between 60-70 and got death wobble… had to peel off onto the shoulder and slow to about 20 before it evened out. After reading around on forums and articles I have a couple suspicions but wondering if anyone can point out an obvious cause…

My concerns are 1:
Casters off due to the 2” springs and I need adjustable control arms.
2: I didn’t do as good as a job with alignment as I think I did and the toe is off
3: tire related issue, possibly need a rebalance.
4: any combination or all of the above.

Any insight would be great, thank you!

 

[txbemis69]

with all the new parts i’d look at the track bar, recheck alignment and tire balance. not exactly in that order. my jeep had a bad front end shake after having a lift installed. jeep also wandered around on the road. it took both hands to keep control of it. redid alignment myself and that cured my jeeps problems. i suspect shop either did not do alignment or did a bad alignment. good luck with this.

 

[andy29847]

A photo of the steering gear from the front could be helpful.

1. What tires and wheels are on a bone stock 2004 Rubicon?
2. Toe in will not generally cause death wobble.
3. Tire related issues are a commen cause.
4. Death wobble is often caused by a combination of things.

here is the "how to" article from this forum: https://wranglertjforum.com/threads/diagnosing-and-fixing-death-wobble.82/

 

[AndyG]

Take a hard look at your control arm bushings especially the right front upper - this Currie kit will help you.

I’ve been told it’s overkill but the problem you run into is you can’t get a new stock bushing to stay tight in the mount usually-

If you’re getting death wobble from hitting a bump it’s likely setting the axle in motion via the track bar because the control arm bushings are not holding it stable, assuming the track bar is all good.

Don’t go by appearances when you look at your joints or anything like that the stress they are under in motion is all that matters

 

[Jerry Bransford]

The 1.75" spring spacer did not reduce your caster angle enough to worry about. An improper toe-in can certainly allow DW to develop more easily so if you're not sure it's correct I'd verify it.

Typically DW is triggered by an imperfectly balanced front tire, even if the tires were recently balanced. Not many tire shops spend enough time to get them balanced well enough to not cause DW or at least the beginning symptoms of DW.
First, are you experiencing full-blown DW? True fully developed DW is VIOLENT beyond the ability to comprehend until you've experienced it. So violent your vision will blur and cars adjacent to you will notice it and get out of your way. And once it is fully developed the only thing that will stop is coming to nearly a full stop. Or was yours more like a shimmy?

The usual cause is an imperfectly balanced tire plus something like the track bar not being tight enough to allow the DW to develop more easily. But to be sure, a badly balanced front tire can also be the sole cause of a bad case of fully developed DW. That happened to me on my previous TJ when it was still fairly new and everything was still tight. The sole cause of the DW turned out one of my front tires entirely lost its balancing weights and it was the worst case of DW I've had since buying my first TJ in 1996.

 

[Jcichy71]

Thanks for the replies…. Yeah it was full on death wobble, I first experienced it in my 04 dodge 3500 after lifting it before I got the alignment dialed in. This was the real deal.

Did have to disconnect my track bar to get the axle to drop low enough to get the springs out and the new ones in… I will recheck the lower bolt is tightened down.

The wheels are bone stock rubi wheels, I do rotate them on a regular basis including the spare. Maybe I’ve rotated a poorly balanced tire onto the front. I will take them to a tire shop ASAP to get them rebalanced.

As far as tires, they are knockoffs that were on there when I bought it. “LAUFENN X Fit AT” 265/75/r16. I bought the jeep at a used car lot, I’m sure it had bad tires and they bought the cheapest thing possible to sell it. That being said, they were brand new and I couldnt see throwing them out when I don’t exactly have money growing on tree’s over here haha. I’ve put roughly 20k miles on them, rotating them roughly every 5000 miles. Still have good tread and tread ware is even.

 

[Shandara]

I recently had DW on my 98 and it was bad enough I had to get down to like 10kmh to get the jeep stable. Even then I pulled to a full stop to check that it hadn't started tearing a wheel apart or breaking the wheel studs. It turned out to be one of the front tires. They were in really good shape 90% tread left. A local shop I had try to road force balance all of them found that the one could not be balanced properly even with rotating it on the rims to several different points. Luckily I have a 4tire replacement warranty that replaced them all for the cost of mount and balance and reupping the warranty. The point is don't over look something because it has been replaced or looks to be in good shape. Having done a bunch of reading on it when I was going through it it seems like tires, worn mounts and track bars seem to come up a fair amount on the list of causes.

 

[Jerry Bransford]

Maybe I’ve rotated a poorly balanced tire onto the front. I will take them to a tire shop ASAP to get them rebalanced.

Have a talk with the guy before he starts your tire balance job, tell him you're experiencing DW and they really need to be perfect. And that if he can't get them perfect ask if he tried rotating the tire on the wheel to see if that helps. I have offered a $20 tip several times over the years if they get them balanced perfectly and it solves the problem. I've paid it twice. And sometimes it takes multiple trips to the shop before they finally figure out they need to get it right instead of "good enough" which is never good enough for the type of front-end the TJ has. Case in point I had to have my tires balanced three times in one day at my local Discount Tire store before they finally got them perfect enough so I wasn't experiencing early development DW. Shy of full-blown DW but still bad enough. The third time was the charm, he spent 3X as long the final time to balance them and they finally drove without the developing DW problem.

 

[AndyG]

Please look at how the design works-


When you hit a bump, it pushes the track bar up and it pushes/pulls against the frame and axle mount points-

Most likely either the track bar then allows the oscillation if it has slop , or the control arm bushings/mounts allow the axle to move if they do or you have enough slop in both to cumulatively allow too much movement -

The bushings allow a little bit of controlled movement and absorb the impact but anything beyond that can contribute/ allow death wobble.

Tires certainly play into it but usually with your set of circumstances you have something allowing it to move more than it should and those are the components that are at play when you hit a bump.

 

[AndyG]

@Jerry Bransford and I formed the Death Wobble Advisory Board and Death Wobble Recovery Center for people just like you.

When you come in we start with giving you a fresh pair of underwear because we know what happened when you experienced it. Then we all sit down and hold hands and share the fear ‘til it passes.

We have some good videos that you can watch of people who have made it through it. Some of them were having it three or four times a week.

We serve snacks and have a nice gift shop.

We have been able to help a lot of people.

 

[mrblaine]

@Jerry Bransford and I formed the Death Wobble Advisory Board and Death Wobble Recovery Center for people just like you.

When you come in we start with giving you a fresh pair of underwear because we know what happened when you experienced it. Then we all sit down and hold hands and share the fear ‘til it passes.

We have some good videos that you can watch of people who have made it through it. Some of them were having it three or four times a week.

We serve snacks and have a nice gift shop.

We have been able to help a lot of people.

This would be a lot more helpful iffen ya'll understood anything about precession.

 

[AndyG]

This would be a lot more helpful iffen ya'll understood anything about precession.

Well I understand enough about precession to know that I don’t understand it-

If I can’t help someone find something loose or a tire out of balance then It is over my head- but I am going to offer what I can.

It is my sworn duty. When I do it people swear a lot.

 

[psrivats]

This would be a lot more helpful iffen ya'll understood anything about precession.

+a million ...

People really have to watch and understand what precession means.

 

[AndyG]

+a million ...

People really have to watch and understand what precession means.

Good stuff. I can’t even comprehend the knowledge base that is out there in automotive alone. Some smart, smart folks.

 

[Mobusaki]

Deathwobble for me one time was due to the lug nut holes being ovaled out. Easy enough to miss if you aren't looking for it.

 

[LJBean]

The timing suggests the DW was caused by the work on your suspension system during spring replacement. Was your Jeep completely off the jack stands when you tightened the control arm bolts?

 

[mrblaine]

Well I understand enough about precession to know that I don’t understand it-

If I can’t find help someone find something loose or a tire out of balance then It is over my head- but I am going to offer what I can.

It is my sworn duty. When I do it people swear a lot.

You don't have to understand precession and angular momentum to visualize what is going on when both tires are spinning the same direction which effectively makes them very large, very heavy and very powerful gyroscopes. The video below needs to be studied at the section where both rotors are spinning the same direction. When the directional input is applied, the immediate reaction is to move one tire up and the other one down. That reverses when the directional input is reversed.

That is why we get the tire oscillation when the locating components are worn, weak, or loose and unable to do their job. In an amongst that is some damping from the shock and overall structure stiffness which helps to keep the harmonics at bay by moving them out of the resonant frequency as much as possible. The point of all of that drivel is it has not a damn thing to do with your description of the trackbar moving up and down and whatever wonky logic you came up with to use that as an example.

Once you extrapolate the forces out to tire sized, it then makes perfect sense why you do not want either of your high force gyros out of balance, not running true and being made to behave by sound component size, strength, and viability. I'm going back to work now so this is the last science lesson you get for awhile. Study the video, you'll be all the better for it.

 

[TheBoogieman]

Who needs Bill Nye when you have mrbaline.

 

[Cross-Threaded-06TJ]

Make sure your frame didn't break in half when you smashed that pothole. I've heard those Northeast coast winters are salty....

I know, you checked it before you bought it. Geez, have your tires balanced and an alignment done.

 

[mrblaine]

Geez, have your tires balanced and an alignment done.

Not for nothing but if an alignment cures DW, what specs do I use to cause DW?