Death Wobble.....HELP!!!!

I've heard the term here on the boards but now I've got my own case. My wife drives a stock '92 w/170k. Its had a bad shimmy in the front end that procrastination didn't fix. Finally I put a put a Rusty's adj. trac bar in it...no help. OK, must be tie rod ends, slightly better. How could it not be, as far as I know, they where the originals. A front end alignment didn't help. Finally I had the 30x9.50 BFG AT's rotated and balanced. Still no fix. This thing has a violent wobble between 50 and 55mph. Its not bad above or below that speed, but in that range, it wants to leave its lane. I've put almost $300 in this thing and I really don't feel like its safe for my wife to drive. ANYBODY have any IDEAS where I need to look next? There's only so many points that tie the front dif to the rest of the chassis!

Thanks for your help.

Bill Owens

What kinda shape is the steering stabilizer in? Is it leaking oil, this could be warn and causing the "D/W" I have had a bunch of Jeeps do this when they wear out.

there's a good write-up on the subject that you can get to from navigating the homepage....

but a little FYI....

suspension shimmy and bona-fide death wobble are two different things....to call it such makes it harder to diagnose on the boards....

if you don't crap your pants when it happens, its not death wobble.

Yeah if ya feel like a SCUD missle just hit your front end and then ya got hit by a train and had to lock up the tires at 60 mph to stop it...... then its DEATH WOBBLE

92' 170k, Ball joints need to be checked, and like you said the TRE's. Then of course make sure your toe is set correctly.

If the wobble/shimmy comes on between 50 and 55 MPH and goes away above 60 MPH it is caused by tire balance. PERIOD! This has been true since before I got my driver's license before most of you lads and lassies were born, and the laws of physics have not been rewritten since then.

TIRE BALANCE -- TIRE BALANCE -- TIRE BALANCE.

Jeff, I looked at the the stabilizer when I did the tie rod ends yesterday. It isn't leaking oil, and when I cycled it, it still felt strong. Besides, I can't believe theres that kind of wobble built into a stock vehicle. Even if you run w/o a stabilizer, the silly thing ought to stay in its own lane.

Beezil and Ted Z, I came awful close to needing that change of underware. I was accelerating thru 50mph on a 4 lane road and when it hit, the truck wanted to dart into the center turn lane. When I corrected, it wanted to occupy the same space as a civic to my right. The whole time there was a violent side to side shaking in the front end. The steering wheel was also shaking back and forth. I think it was a bona fide case of DW.

Chuck, the ball joints are one thing I haven't checked yet. BTW do you happen to know the correct toe. I'd like to do the "tape measue in the driveway" trick to double check meinecke's work.

Eagle, with all do respect, I've never felt an out of balance tire feel that bad, especially when it still happened after getting out of Sam's tire center for a rotation and balance. The tech. said that three out of the four rims didn't even have weights on them! I says to myself, aha! that must have been the problem all along! I was very dissapointed to shake my way back onto the intersate. I will say this, the tech said he used the tape on weights on the inside of the rim to keep from dinging up the outside. I appreciated that but don't know if that is the best way to do a balance. Whats your opinion? I think I'll go back today and have them use the old style weights, I don't think it can be any worse. (Famous last words)

Thanks Y'all I'll look at what you mentioned and let you know what happens.

Bill

As an update, I just put a new steering stabilizer on...my problem is now MUCH worse. What in the world is going on!!!! While it was up on the rack for another tire balance I checked the ball joints and they felt nice and tight. Much head scratching is going on around here. Thanks for letting me rant.

Bill

Eagle said:

If the wobble/shimmy comes on between 50 and 55 MPH and goes away above 60 MPH it is caused by tire balance. PERIOD! This has been true since before I got my driver's license before most of you lads and lassies were born, and the laws of physics have not been rewritten since then.

TIRE BALANCE -- TIRE BALANCE -- TIRE BALANCE.

Click to expand...

Sorry Eagle but I have to disagree. I had the wobbles bad last week it started between 40-45 and by the end it was from 35-55. I got under her and went to town checking everything. I found the tracbar loose at the frame, LCA's had 3 loose bolts, and the alignment was off by about 1/4" between the front and rear of the tire. I fixed all of this and it went away completely.

Before I fixed it I tried something and found some interesting results. I have a theory that the wobble is caused by an oscillation that is not just and up and down motion. So I dropped the tire pressure down to around 15psi and drove around. The wobble was gone. So my theory is that the tire is translating the lateral movement of tire in to an upward movement of the wheel. By droppind the tire pressure the tire didn't have the same force applied to the wheel. I then reinflated the tire back to 32psi and played with my shocks. Again I started with my shocks(Rancho RS9000's) on number 3 and the wobble was there I turned it up to 4 and the wobble was noticably less forceful, at number 5 the wobble was very hard to get going and had lost much of it's force but it was still there although it was minimal compared to number 3. Note that I haven't been running a swaybar since January so it may have alleviated the symptoms if it was attached I didn't test it so i don't know.

This leads me to believe that tire balance is only part of the wobble effect.

FatXJ --

The start of your post indicates you did not rear what I wrote.

If the wobble/shimmy comes on between 50 and 55 MPH and goes away above 60 MPH it is caused by tire balance.

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You can have shimmy without having death wobble, as Beezil noted. "Death wobble" is what happens when the shimmy or wobble in one wheel is transmitted through the steering components and suspension and sets the opposite wheel in motion. If the two wheels happen to hit a harmonic reinforcement, the wobbling escalates exponentially and you have the proverbial death wobble.

If you have something happening that starts as low as 45 MPH or 35 MPH, there's something more going on than simple balance. However, I stand by my statement that if the shimmy starts at between 50 and 55 MPH (usually 55) and disappears above 60 or 65 MPH, the cause is wheel balance.

Bill01s -- unless the tire is of exceptional quality, it isn't possible to balance it correctly using weights on the back and nothing on the outside. The tech undoubtedly was sincere in thinking he was doing you a favor, but in fact he doesn't know $hit from Shinola about balancing tires.

Eagle, your desription of the transmision of the wobble thru the steering components makes sense. I actually watched the front tires (well at least the left front with my head out the window)shimmy left and right as if the steering wheel was being turned left /right. The only problem, I was going 50mph! It was so bad at one point, the tires were "chirping" during their side to side cycle. I will promptly get it back to the shop and have the tires balaned correctly. BTW I retorqued the upper and lower arms...no help.

Bill

What are your caster and toe-in settings? Caster should be at least 6 degrees, and toe-in should be zero when checked dynamically.

I had a bad case of this when I lifted it and still had the stock tires on alloy wheels. I added new steel wheels and 32" mud tires, and no more wobble. I guess it was because they were out of balance or the tires were just screwed up, but what Eagle is saying is what he told me when I first asked. (Thanks by the way ). Let us know when you have them rebalanced.

Andrew

Eagle I know the difference between death wobble and just the wobbles in general. When I first got my Jeep it had death wobble that literally required all my force to keep it on the road while I slowed down to stop it. The cause was a bent tierod that had the alignment gone to hell.

The wobbles I felt last week were not as bad and were not really noticeable through the steering wheel as much as the whole vehicle shook. Once it got to the point that it started shaking the steering wheel then it was going from 35-55 mph. It still was more noticable in the body shake and didn't take me off the road with ghost steer.

So neither one of my wobble experiences were caused or at least fixed by rebalancing my tires. I know for a fact that my tires are not balanced anymore because I have chunks of rubber missing and a couple wheel weights have come off as well. I do know that I have no wobbles now at any speed from 0-100 mph. At least none that I can feel through my incredibly stiff suspension. So in my opinion you can't say that a wobble that comes in at 50-55mph is any different than one that starts at 40 and goes away like mine did. If all else checks out ok then it may be tire balance but tire balancing costs money checking suspension components doesn't unless you are mechanically uninclined.

Don't go spending money on something you might not need!!!

FatXJ said:

So in my opinion you can't say that a wobble that comes in at 50-55mph is any different than one that starts at 40 and goes away like mine did.

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You are entitled to your opinion, but I CAN say that, and I DID say that, and I stand by the statement.

My post was not in response to your situation, it was in response to the original question, in which Bill wrote "This thing has a violent wobble between 50 and 55mph. Its not bad above or below that speed, but in that range, it wants to leave its lane."

I submit that Bill's symptoms are classic indicators of poor wheel balance. The fact that the tech specifically stated he did not put any weights on the outside of the rims only confirms it.

Your situation was different, because it involved a much wider range of speeds. Don't confuse apples and oranges. I have never been able to explain why 55 MPH is the magic speed, because it appears to be the same regardless of tire size, but shimmy or wobble that appears at 55 and disappears over 60 is due to tire balance, and that's been the case since long before you were born.

yall need to read this book.......

beez u r cracking me up my sides hurt :laugh: :roflmao: :worship:

I said I'd let you guys know what happened but its been a hectic couple of days. Eagle, I'M NOT WORTHY!!!! I never would have thought that tire balance could possibly make that much difference. The XJ went from dangerous to drive to feeling like it "just" has a tire out of balance. I must say that the 30x9.50 BFG ATs have 50k on them and are 4 yrs old. I didn't catch the front end alignment and cupped the front tires(which are now on the rear). I'm sure that this accounts for some of the vibration I now have. I can also "induce" a much less severe wobble if I can keep it at about 53mph for long enough. I think this is still a problem w/the old tires. I'm sure they're hard to balance.

Things I've learned:

If you take care of basic maintenance, you don't have to wonder about whether or not you have bad tie rod ends, ball joints, etc.

Keep the tires balanced(the right way) and rotated. Thats why you bought the warranty, right?!

Stay on top of the front end balance. I probably could of got another 10k out of the BFGs if I hadn't cupped them.

Finally, respect your elders. When an old bird tells you something, he may just know what he's talking about!

Thanks to everyone that chimed in, every post made me think about and check things that I should have done all along.

Bill

I'm just glad to know your XJ is safe to drive again.