Death Wobble Question

taylormade73

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I have DW that only occurs when hitting specific bumps while at speeds above 30mph. No other vibes, shakes or rattles at any speed. Smooth as glass otherwise.

With this said, could tire balance be an issue?

I know improperly balanced tires are a common cause of DW. But, I would think that improperly balanced tires would create a speed specific DW that didn't require hitting a specific type of bump or would create vibes or a shake as well outside of the DW events.

Am I off on this thinking? Reason I ask is with my ride being smooth with no vibes, I don't want to potentially introduce a new issue-while tracking down the cause of my DW-by letting a shop fuck with my tires if they're already balanced well.
 
You would feel vibration at certain speed if it was primarily a balance issue.
If it happens after hitting a pothole or a bump it means worn parts.
I went through the exact same thing. I ended up replacing the track bar, steering linkage, control arms and sway bar bushings.
Now it's great.

Do a dry steering test, put your hand on each part and check for any play, replace those parts.
 
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If the tire is unbalanced, hitting a bump will increase the oscillation. You’ll feel this as a wobble.

I disagree that all wobble is a sign of worn parts. If you have worn parts, the oscillation can increase to death wobble, but even a Jeep with new steering and suspension can experience wobble if a tire remains unbalanced.

For years, I put faith in the techs at Discount Tire to balance my tires properly. It wasn’t until I pointed out that the tires needed to be perfectly balanced that the wobble after hitting bumps went away.

Get your tires balanced and politely inform them that they need to be perfect or you’ll feel it. They should road force balance the tires to “0”, and they will if you request it.
 
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Yes, I didn't mean tire balance is not part of the cause. I had my tires rebalance as well. New ball joints too.
 
I have DW that only occurs when hitting specific bumps while at speeds above 30mph. No other vibes, shakes or rattles at any speed. Smooth as glass otherwise.

With this said, could tire balance be an issue?

I know improperly balanced tires are a common cause of DW. But, I would think that improperly balanced tires would create a speed specific DW that didn't require hitting a specific type of bump or would create vibes or a shake as well outside of the DW events.

Am I off on this thinking? Reason I ask is with my ride being smooth with no vibes, I don't want to potentially introduce a new issue-while tracking down the cause of my DW-by letting a shop fuck with my tires if they're already balanced well.
The primary part that is affected when you hit a bump is the track bar.. bump activated death wobble usually means it is loose or you have worn bushings or a compromised fastener.

You can also have other steering components that are contributing... Remember four components that move 1/32" are the same as one component that moves 1/8".
 
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It's not the tires. They balanced out to 0 on all 4 and it still does it. Only 1 was out of balance and it was on the rear. They did a steering test and said all joints and ends are tight, including steering box. They checked and verified that all bolts are torqued to spec.

One of the senior guys there was pretty cool. He told me to bring it back tomorrow morning and we'll put it on the rack and he wants his mechanic to look at it as well. No charge; he's just curious as well.

We'll see! TBC.
 
The primary part that is affected when you hit a bump is the track bar.. bump activated death wobble usually means it is loose or you have worn bushings or a compromised fastener.

You can also have other steering components that are contributing... Remember four components that move 1/32" are the same as one component that moves 1/8".
Yes! This
 
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the track bars' job is to keep the axle centered by lever force when the Springs compresse and the axle moves up and down.. which is exactly what happens when you hit a bump.

Your wheels are trying to track straight by gyroscopic force and the inherent tracking that a rolling wheel has

If the bar is loose , the second everything shifts from the bump the tire tries to correct itself and the loose components allow it to
then overcorrect... And then it immediately goes the other direction and begins oscillation.. as the tire is trying to correct its path and the axle is slightly moving the other direction because of the play in the track bar... At this point the tail is wagging the dog.
 
My TB is a new Currie installed on a new Currie housing. Axle side torqued to 75 ft lb and frame side torqued to 125 ft lb. I've rechecked torque on them and very other fastener 3 times in 3 days. I also marked all fasteners with a paint marker after torquing. None have moved. I also have Currectlink steering and Savvy double adjustables with 5k miles on them since install. BJs are new with housing that I just installed 6 days ago.

20200714_190729.jpg
 
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A dry test tells you everything on the track bar , and @Mr. Blaine helped me realize your passenger side upper front control arm can come into play with death wobble, I don't know why.
 
16-17 weeks.
Do you have another set of wheels and tires to throw on the front. My theory is your tires have flat spots from sitting. When I bought my LJR it was sitting for 3 years and had very bad DW similar to yours. I replaced everything all at once so don’t know what was causing it but this was one of my suspicions.
 
I think it just means something is loose. That's what bump induced wobble is to me. If it's balance it happens no matter what. Blaine has suggested this at least once, set your toe neutral or a bit toe out. If it reduces the wobble then it points to your front upper control arms. It is an easy test I'd try. Loose control arms are difficult to test just by pushing on them.
 
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Is it any bump? Or can you replicate consistently if you hit a pothole on one side or the other? If that's the case also check balljoints.
 
Is it any bump? Or can you replicate consistently if you hit a pothole on one side or the other? If that's the case also check balljoints.
Not any bump. Hell not even 95% of them. Not even all pot holes. Only bumps that cause the wheel to come off the ground slightly.
 
I had DW and replaced the track bar and that solved the issue for a period of time. Then it came back. Then I did the ZJ tie rod upgrade and that solved the problem and things have been bueno for at least six months now.