Another source of death wobble not usually considered

I don't believe that's a safe assumption, given what I see on the FB jeep groups, but also simply based on the replies in this thread. There are different classes of vibrations & wobbles, and depending on what you've personally experienced it is easy to think you've encountered one when you actually encountered another. Several of us have lived through a thing you can't throttle out of, which is why we tried to drill into your specific experience, but you weren't super interested in that line of questioning.

truth. If I had a nickel for every time someone used "death wobble" for just an annoying wobble or shimmy that's hard to get rid of, without realizing the "death" part of the name isn't actually hyperbole.

It seems like you just wanted to tell us about the importance of axle alignment (is this what the shops call "thrust angle?"), which I don't think anyone here would disagree with in the slightest. It's definitely not talked about much, but with as many people running adjustable arms all the way around, I'm sure it's actually a much bigger thing than people realize. I know I've never measured mine. ¯\_(ツ)_/¯

I always thought of thrust angle as specific to rear axle as it contributes to "dog tracking" where the vehicle looks like it's running down the road sideways. I think the front axle being out of square would show up as a pull, if at all.

Whatever it does I'm sure it's another contributor to people using "it's a jeep" to excuse poor road manners. Checking axle square to frame and to each other has always been the last step in my alignment process but maybe it's not as common as I'd assumed.
 
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Sorry, what I have experienced was death wobble, not a shimmy. If you were there you can comment, otherwise move along

The axles are what they are. You adjust the Control Arms for the pinion. Unparallel axles is not a cause of DW, shimmies, shakes, et. al.

The common sources of DW are pretty much known. Start with tire balance and get them perfect, also check steering components. front trackbar is a problem about 90% of the time (hole being wallowed out is not the problem, improper torque is), keep going down the list, TR ends, CA bushings, et. al. There's no reason to re-invent the wheel here. Most people on here have had DW, shimmies, shakes, and some have had bump steer due to drop Pitman Arms, so quit acting like you discovered a pot of gold with the parallel axles theory.
 
The axles are what they are. You adjust the Control Arms for the pinion. Unparallel axles is not a cause of DW, shimmies, shakes, et. al.

The common sources of DW are pretty much known. Start with tire balance and get them perfect, also check steering components. front trackbar is a problem about 90% of the time (hole being wallowed out is not the problem, improper torque is), keep going down the list, TR ends, CA bushings, et. al. There's no reason to re-invent the wheel here. Most people on here have had DW, shimmies, shakes, and some have had bump steer due to drop Pitman Arms, so quit acting like you discovered a pot of gold with the parallel axles theory.

chill man, not claiming any such thing. just sharing my personal experience about having DW and it was fixed after i made the axles parallel. hard to argue with experience. no need to continue this conversation. have a cold one and find something else to talk about
 
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my jeep had the shakes after having the lift installed. poor road conditions would set it to shaking. jeep would also wander all over the road and took both hands to try to keep it straight i questioned in my mind wtf is wrong with my jeep. before lift you could drive with one finger. everything suspension and steering wise looked good and all was tight. i finally said to myself, i wonder about the alignment? a simple home alignment and i discovered that the shop either a. didn’t do alignment after lift was installed or b. did a bad alignment. a simple home alignment now has the jeep back to driving with one finger. was it death wobble? i think not.
 
In my case, death wobble was triggered at speed by a disturbance in the road, like freedom in 4low. And yes, after experiencing it a few times, I could sense the speed at which it was about to happen, maybe a hint of wheel shimmy that could trigger death wobble, where slowing down or speeding up would avoid it. However, I don't think unparallel axles are the problem. Then I replaced my track bar to fix the issue.

The bottom line is that if death wobble is happening, something is loose enough to not be doing its job (almost always track bar). I subscribe to the DWWTH theory.
 
My DW experience happened almost anywhere at any speed between 25 and 60 mph and the first time was about 10 miles after I bought my TJ. It seemed like any road gave it various reasons to start DW and no matter what speed it happened at, slowing the Jeep down to almost stopped was the only way to end it.

The bottom line is that if death wobble is happening, something is loose enough to not be doing its job (almost always track bar). I subscribe to the DWWTH theory.

The first thing I did was replace the track bar because it seemed too loose in the dry steering test. I must have been wrong about "too loose" because the new Mood track bar may have been a little tighter but still allowed similar movement in the rubber bushings and my DW remained in place. So I got an alignment from the only mechanic I trust which fixed massive toe in but the DW didn't care. At that point he said the wheels stuck out too far throwing off the scrub radius. I thought he was crazy but he put tires/wheels from one of his own cars on the front axle and told me to drive it like that for a day or two. My TJ's DW was MIA with those tires/wheels so I found a set of original Moabs to match the spare that was still on it. It's been over 4 yrs now and the DW hasn't been back.

Here Jack is putting one of his tires/wheels on my TJ and you can see my ugly wheel beside him.
20180530_112428.jpg
 
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My DW experience happened almost anywhere at any speed between 25 and 60 mph and the first time was about 10 miles after I bought my TJ. It seemed like any road gave it various reasons to start DW and no matter what speed it happened at, slowing the Jeep down to almost stopped was the only way to end it.



The first thing I did was replace the track bar because it seemed too loose in the dry steering test. I must have been wrong about "too loose" because the new Mood track bar may have been a little tighter but still allowed similar movement in the rubber bushings and my DW remained in place. So I got an alignment from the only mechanic I trust which fixed massive toe in but the DW didn't care. At that point he said the wheels stuck out too far throwing off the scrub radius. I thought he was crazy but he put tires/wheels from one of his own cars on the front axle and told me to drive it like that for a day or two. My TJ's DW was MIA with those tires/wheels so I found a set of original Moabs to match the spare that was still on it. It's been over 4 yrs now and the DW hasn't been back.

Here Jack is putting one of his tires/wheels on my TJ and you can see my ugly wheel beside him.
View attachment 361931

Large scrub radius is not the root cause of DW, but I don't doubt that backspaced wheels alleviated one of the factors that make it easier for DW to occur. Decreasing scrub radius is a great way to decrease overall stress on the steering components and improve handling.
 
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Large scrub radius is not the root cause of DW, but I don't doubt that backspaced wheels alleviated one of the factors that make it easier for DW to occur. Decreasing scrub radius is a great way to decrease overall stress on the steering components and improve handling.

I used to run 3.625” BS. My recent wheel change is partially an experiment with BS. I’m now at 4.5”. The difference in handling is clear onroad. Off-road I thought it would be too cumbersome rubbing arms or the SwayLoc, but it’s really not much different than before. All in all I think this is a good move so far. If it turns out too many negatives show up I’ll add some 0.5” spacers to bring it where most people say is ideal (4”).
 
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