In need of Death Wobble Diagnosis...
 

Hey all.

So I bought my JK November 2015 and immediately installed 3.25" suspension lift from rough country. Once lifted, I had my stock wheels on for a few months until putting on 35's (I also installed a $70 steering stabilizer from rough country). Once November 2016 rolled around, I switched back to the stock tires for the winter. This is when I first got the DW but I would only get it going 70 mph or faster whenever I hit a big bump or expansion joint on the highway....no big deal. March 2017 comes and I throw on the 35's. No DW whatsoever. November 2017 and I switch back to stock wheels for winter. Now im getting DW every little bump I hit going over 60 mph.

I didn't upgrade my track bar which I presume may be the culprit as it is in many DW cases.

Im only getting DW with stock wheels so I could just keep the 35's on but wanted to preserve the wheels driving on the salted roads of Cleveland Ohio hence I'm switching back to stock.

I'd appreciate any insight or recommendations!

Deathwobble? Or Shimmy? From the description, it doesn't sound like full-on shit the pants have to pull over and stop to get it to go away deathwobble.

https://www.jk-forum.com/forums/jk-w...obbles-260145/

If it only happens with the stock tires, have them balanced. Twice if needed. Then go through that writeup a few times and check all the components, not just the trackbar. Removing the stabilizer may help narrow it down if it is comoponent related and not just tires.

Thank you for posting the link. That was very helpful and I will definitely check all of those components as soon as I can. As far as the shimmy vs full wobble: I can only get it to stop once I slow down to about 30 mph and it is definitely a violent harmonic resonance so I believe it to be Wobble however it does subside by slowing down and I do not have to come to a complete stop. I'll update you as I work toward a solution. Thanks again.

I don't think you have "death wobble". I think the ESC is kicking because of the bouncy RC springs. Factory shocks or oil shocks? The computer is reading the road irregularity as loss of control and your Jeeps is activating the ABS and ECS to get control. Dash lighting up like a Christmas Tree when it happens?

The alignment specs between the stock tires and 35s can vary a lot as well. If you had your alignment done by a 4x4 shop with the larger tires, they will sometimes put a toe out. This won't work as well with the stock tires. Depending on the driving you've done, there is a fair chance that you're dealing with wallowed out track bar bolts, worn ball joints, or even just a really low castor angle.

Ima bet $5 this has not been addressed. Not the root cause of the issue, but not helping any either.

I also question your description of DW......cuz REAL full on DW is the kinda thing that will indeed freak you the F out and bring you to a complete stop. It's not something that you keep driving with and have it trigger every time you hit a bump over 60 mph. Is that $70 RC steering stabilizer gas filled unit?

If you've retorqued all components to spec, inspected for worn joints and such, then by all means get those tires balanced good. I suspect though that you're still getting some effects with the 35s on.....maybe that it's just being masked more with the larger tire.

It's a good opportunity to get intimate with your steering components!

Hey guys sorry I haven't replied but just worked on the jeep today and here's the latest. I replaced my tie rod ends because they were pretty loose. I also put on a new RC adjustable track bar.

My current RC steering stabilizer is probably junk but I did not replace that yet. I'm not sure if it's bad filled... I also noticed my drag link was loose at the ends so I believe I need to replace that also.

When test driving after today's operation, my dash was lighting up with abs and ecs. I'm going to get it aligned tomorrow so will an alignment fix the abs/ecs issue? I also am still getting DW. I know you're questioning whether it's full DW or not but it shakes so violently I feel my wheels fall off if I don't slow down so in my opinion it's full DW but subsides when I slow to about 40mph.

As far as castor angle, I'm not quite sure what you mean or how to address that.

The alignment sheet will show what the number is.

When you add a lift, the axle housing rotates - the pinion points further up. As this happens, the caster automatically goes down. Stock caster is around 4.2 degrees. With a 3.25" lift, the printout might show it at little over 3 degrees, maybe? As this number goes down, the steering gets progressively flightier. Not deathwobble, not bumpsteer, just wandering.

To address it, you need to add components to rotate the housing back down. Cam Bolts, Drop Brackets, longer/shorter Fixed Control Arms, or Adjustable Control arms. (verify that you do not have cam bolts now, they sometimes come with that lift from RC. It looks like a big washer, but with the hole toward an edge and not the middle, and will be on the axle ends of both lower control arms. see post #16 in this thread)
https://www.jk-forum.com/forums/modi...-issue-345178/

For the dash lights, is the steering wheel straight? Or turned to one side a bit while you are driving straight?

it's turned to one side while driving straight!

On the draglink, loosen the two bolts, twist the turnbuckle, then check the steering wheel. When centered, tighten the bolts and go for a drive. Or have the alignment shop do it. Should take care of the that issue, at least.

It would seem that several jeepers tend to forget that balancing a 35" (or greater) tires is very difficult. Often the shops doesn't have the manpower to effectively & correctly mount & balance these tires with the use of lesser installation equipment. Although I could go into a full detailed check list here, one of the main culprits would be the balancing of these tires. I would have the tire rebalanced by another shop who has the correct balancing equipment. Worn bushings, would be the next area to address. Then let's test the shocks, onward to the tires PSI, Not to mention the wheels being either hub centric or lug centric, as all of these things can't be ruled out. Inferior installation techniques and poor geometry can all have an effect on the vehicles handling.

Ok well I got the front end aligned and had them balance the tires. And remember, right now the tires I'm running are stock. The mechanic that did the alignment had experience with jeeps and said he believes the wobble is a tire issue because the wobble goes away when I am running the 35s. (I thought this was because the wider wheel base would dampen the resonant frequency causing the wobble, but he seemed to think that if the issue was with anything other than the tires, the larger wheels would make the wobble worse).

After aligning and balancing, and airing to about 30 PSI, I still felt a "Shimmy" when going over uneven expansion joints on the highway. Because of this I didn't feel comfortable pushing the speed past 65. I feel like if I hit a joint at 65, it would have went into DW.

Next, I'm going to look into upgrading my steering stabilizer. I know what people say about the stabilizer not FIXING the problem, but if the stabilizer is stabilizing the front end and preventing me from getting a wobble I don't see the issue with it.

Backing all the way up to the OP, let’s see if we can pin down some details and recap things:

Jeep bought in November 2015, at which time RC 3+” lift installed. Stock tires used for a couple months, then switched to 35s.

November 2016 rolls around, you put factory tires back on for the winter. This is when you first noticed signs of a wobble.

March 2017 rolls around, and you put the 35s back on for spring/summer. Wobble appears to have disappeared.

November 2017 comes and the factory tires go back on, and you’re getting a wobble at every big bump ~60mph.

You’ve replaced the track bar with a RC adjustable track bar.
You’ve replaced TREs as the old ones were loose.

No mention of offroading, so presume this is pretty much a pavement rig. No mention of alignment specs….can you post your current caster just so we know (Nthinuf was trying to get this out of you earlier)? Can you post your alignment sheet? No mention of specific build specs in your profile, so I also presume no drag link flip? No mention of ball joints having been replaced in the past, so presume they are factory. These are all just minor details, but helpful to know.

Here’s my 2c. I think you likely have a crap ball joint. Keep in mind that driving with 35s is going to put added stress on all steering components. Those factory ball joints (if that is indeed what you still have), are crap. They have plastic internals and just don’t stand up long to larger tires. If you have a couple years of wear on them with 35s, even if just partial years, that alone could be enough. It is probably the most likely thing. The track bar and ball joints are the most common culprits for a wobble. I think that the issue is really still there when you swap to the 35s, but it’s not as easily triggered, maybe because the 35 is soaking up more of the bump or reaction then the factory tires is….not so sure bout that necessarily, but I don’t believe the wobble itself is due to the tire.

If the wobble was tire related (like an out of balance tire), I would think that driving along on a straight path, a wobble would start to generate/build as speed increased. I have had DW induced by an out of balance wheel after wheeling (wheel caked in mud) myself. Culprit was loose TB bolt and bad BJ, but tire triggered it. Anyhow, it sounds like you are saying it takes a bump in order to trigger this….then things go crazy. That right there makes me think this is NOT an out of balance tire issue. I can also envision this being worse with the smaller tire….lighter tire, less stability, easier wobble around…..even though the 35 has much more mass. I’m no scientist, I’m just thinking out loud trying to make some sense.

Assuming you didn’t have any wallowing at the frame side TB hole when you replaced that, and that every suspension and steering component is torque to spec, I will bet dollars to donuts that you have a BJ issue. You’ve read it 1000x I know, but putting on a new steering stabilizer isn’t going to solve it. It might mask it a bit more, but the underlying issue is still going to be there. If you just want to cover it up even better, install some hydro assist steering. You should be able to drive that jeep with no stabilizer at all and not even notice.

Also, to lead back to the alignment stuff….if your caster is too low, or if you are a good candidate for a DL flip, those things aren’t helping your issue. They aren’t CAUSING the issue, but are probably leading to some bump steer which isn’t helping at all.

Did you test your ball joints with a shovel or something under your wheel?

Resharp, thanks for your detailed post and analysis. I appreciate you taking the time.

Everything you summarized is correct. Just to note, I did take the jeep offroading twice around august and september just before swapping back to the stock wheels.

I'll post my alignment specs sometime tomorrow if I remember. I don't have the sheet with me right now.
No Drag Link Flip
Yes, factory BJs

And as I mentioned before, the guy doing my alignment said the 35's would make a wobble worse so he says the issue is with the stock tires, however I tend to agree with you that the 35's being more massive are harder to throw off so the issue is with another steering component (BJs for example). So to me, in a way the 35s are like steering stabilizers in their own way.

I did not test the ball joints with a shovel. I'll be sure to do that. Also, there was no wallowing of the factory TB bolt hole. And yes, everything was torqued with a 400 ft-lb impact wrench so no doubt nothing is loose.

And to add another piece of info, I increased my tire pressure from about 30psi to 40 psi and the bump steer I was getting was noticeably reduced but not entirely eradicated.

I dug back up through the thread but don't see a mention of your mileage...but you're a couple years in now, and some of that is on 35s. I really suspect the ball joints, especially since you note they are still factory. Keep in mind that the factory ball joints have plastic internals. New Google changes have made it difficult to easily embed and image, but check this link for pic -

https://goo.gl/images/C4vnAk

That is the big reason that BJ are a common issue on our JKs. One crack in that plastic and they're toast. I typically jack up the front axle till tires are a couple inches off the ground, slide couple jack stands under it to stabilize, then stick a shovel under the tire, stepping on the handle...using it as leverage to force the tire upwards. Shine some good light right there where the knuckle meets the C (both upper and lower) and watch for movement. There shouldn't be much play at all. If you don't have jack stands, you can just jack up one side at a time.