Interesting insight on death wobble

[dcritzer]

I have a 2020 Sport S. I bought in May and swapped out some 33's from a JL Rubicon when it had only 400 miles on it. A month ago I decided to put the stock tires back on it to see how much difference it would make with fuel mileage. (it went from 18 to 22 mpg with the stock tires back on)

It was about 30 degrees out and I hit an expansion joint at about 75 mph on the interstate and discovered what death wobble was. It happened three more times that day. I took it to the dealership and after 3 days, they force balanced the tires. The service manager stated he has only seen this happen with the stock tires (Bridgestone desert duelers) that come on the sport and sport s. In addition, it only happens when the temperature is cold. I suspect it is a combo of stiff walled tires and the viscosity of the oil in the steering stabilizer create the ideal situation for death wobble to occur.

This apparently happens so often that the Fiat Chrysler forbids their employee from using the term death wobble.

Of course the dealership's answer is to replace the steering stabilizer. It is on back order for at least a month. Jeep wave is absolutely useless in helping resolve the situation. I was warned about the lack of customer service if I bought a jeep/Chrysler product. They could learn a thing or two from Lexus. I think I'll just put the bigger tires back on and be done with this BS.

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[Rahkmalla]

steering stabilizers do not fix death wobble. They are a bandaid. You may get lucky that the bandaid sticks for a while, but it will fail. Tire balance is also not the cause of death wobble, so a road force balance is just another bandaid (a less effective one IMO). Though unbalanced tires could be the culprit that caused the problems that lead to the bushing wearing out that are now responsible for death wobble. But fixing tire balance after the fact is pouring water on the barn after it's burned down. You want balanced tires always, but they wont fix the wobs.

as for only happening on one type of tire wobbling, and it only happening at one temperature, that's garbage. It does seem to be more common when cold, but only cold? Joke. Only one type of tire? Joke.

 

[Mjolnir]

steering stabilizers do not fix death wobble. They are a bandaid. You may get lucky that the bandaid sticks for a while, but it will fail. Tire balance is also not the cause of death wobble, so a road force balance is just another bandaid (a less effective one IMO). Though unbalanced tires could be the culprit that caused the problems that lead to the bushing wearing out that are now responsible for death wobble. But fixing tire balance after the fact is pouring water on the barn after it's burned down. You want balanced tires always, but they wont fix the wobs.

as for only happening on one type of tire wobbling, and it only happening at one temperature, that's garbage. It does seem to be more common when cold, but only cold? Joke. Only one type of tire? Joke.

OP,

I can not stress how RIGHT of an answer this is, good lord.

 

[dcritzer]

Just my observations so far. Cold with stock tires=death wobble. If it is above 50 degrees no wobble. Bigger tires (KO2's) no issues at any temperature. Going to put Ko2's back on this afternoon. It is supposed to be cold in Virginia the next few days. I will see how it goes...

 

[ShadowsPapa]

So after some of the best performance engineers, steering and suspension engineers in the world working on this for over 6 decades (that's over 60 years)
You have it solved.
Frankly, you have a way to stop the symptoms on your truck.
Others would argue because they have seen it in warmer temperatures with other and bigger tires.

The service manager stated he has only seen this happen with the stock tires (Bridgestone desert duelers) that come on the sport and sport s. In addition, it only happens when the temperature is cold. I suspect it is a combo of stiff walled tires and the viscosity of the oil in the steering stabilizer create the ideal situation for death wobble to occur.

Your dealer shop has seen their little world, the trucks they sell and/or service.
The stock tires aren't really stiff-walled. The Rubicon A/T tires I ran for a while were pretty stiff tires compared to my current tires.

Odd - I'd expect a stiffer stabilizer to actually work against that wobble - which is really a radical shimmy. If they've only seen it with those tires, then there's a situation with THOSE specific tires, not the stiffness of the sidewall otherwise others with higher load rating tires would experience it.

It just happened to be that combination of events and parts that caused it in your case.
Otherwise, it's a decades long issue, has happened with all types and sizes of tires, and even in warmer temperatures.

Though unbalanced tires could be the culprit that caused the problems that lead to the bushing wearing out that are now responsible for death wobble.

This from Norm Layton -
"Jeep death wobble" is basically a shimmy, and can affect any suspension with a continuous tie rod (which nearly all solid axles have) to connect the front wheels.
"Shimmy is normally cause by aftermarket application of larger tires, lifts that change the front axle setting for toe, or caster and camber, or worn or damaged parts. An out of balance tire, a broken tire cord, a bent wheel, or worn shocks can be the cause."

On a properly designed and well maintained system, a damper's purpose is to mitigate the effects of bump steer and the sudden encounter of unexpected objects, such as hitting a rock in a trail at 50 miles per hour. On an improperly designed and/or poorly maintained system, a damper is used as a crutch to mask issues with suspension and tire errors.

Jeeps and other vehicles experienced shimmy way before the 1960s, and before the advent of lifts and larger tires. Worn components are just as much at fault as jury-rigged suspensions.

 

[dcritzer]

totally stock 17k miles. shouldn't be happening.....gets better if I change tires. Go figure. and it is damn sure not a shimmy. It's like the whole vehicle is trying to shake apart.

 

[redrider]

Wobble is not unique to Jeeps. We motorcyclists have been dealing with this forever. Technology has done a lot to mask the phenomenon, but it still occurs. As others have posted, there are a lot of variables but my belief is the shorter wheelbase and weight distribution/balance are the base culprits just waiting for one insignificant thing to upset the apple cart. Youtube has the Dunlop Tire wobble story from the early 70's. Two wheels, not four but the engineering demo is convincing. Many different models shown, they all do it with the right/wrong input.

 

[ShadowsPapa]

totally stock 17k miles. shouldn't be happening.....gets better if I change tires. Go figure. and it is damn sure not a shimmy. It's like the whole vehicle is trying to shake apart.

You are arguing with world-class suspension engineers there - it is a shimmy, a radical one, but that quote is from a guy who has done more with Jeeps and performance than any member of this forum.
Go ahead, look him up. I can give you another name, too, a guy who engineered suspension and steering for Jeep and other companies and has worked around the world.

Here is a quote about Norm (dead in 2015)
Norm Layton is a long time Mopar guy; he owns Sweptline Products and is a sponsor as well. Sweptline restores Power Wagons and modifies Jeeps. Norm was directly involved in the vehicle fabrication, spending 3-4 days per week at All J in Big Bear, California. Every detail about this vehicle resides in someone’s head. There are no schematics, no CAD drawings, no written specifications.

 

[Wbrook24]

Then you probably have worn out bushings and the tire swap may have sped up the process. Very possible putting old tires back on won't help.

 

[ShadowsPapa]

Wobble is not unique to Jeeps. We motorcyclists have been dealing with this forever. Technology has done a lot to mask the phenomenon, but it still occurs. As others have posted, there are a lot of variables but my belief is the shorter wheelbase and weight distribution/balance are the base culprits just waiting for one insignificant thing to upset the apple cart. Youtube has the Dunlop Tire wobble story from the early 70's. Two wheels, not four but the engineering demo is convincing. Many different models shown, they all do it with the right/wrong input.

Definitely not unique to Jeep.
Try experiencing it with a 95 F250 4x4
Big heavy truck, heavy duty suspension and brakes, big heavy STOCK tires. It was fine until about 80,000 miles. Then it got squirrely. Not the exact same as I never had it harsh enough I had to stop to get it to quit, but $2,000 dollars of parts later, it was still happening to some extent. By-by F250.
Ford people have talked about it, as have owners/drivers of other similar vehicles. And the Ford design isn't exactly the same as Jeep.........
Every single bushing, joint, tie rod, you name it, was replaced. I literally said "we're replacing everything there is", including the spring bushings.
The steering knuckles were not replaced and as time went on after I traded, I wondered........ because the truck had been hit on the left front wheel years prior, but it always "aligned" ok.

 

[Artsifrtsi]

The stock tires could also be improperly inflated, this will, and does cause the shakes and shimmies as well. DW is a symptom of a issue. Usually the initiate is unbalanced rotational masses, that gets exacerbated through a loose system of joints. The looseness of the links allow the oscillations to magnify and become the DW. Changing out joints, correcting alignment, making sure all joints are correctly torqued, and stabilizers only mask the symptoms or prevent the oscillations from becoming cyclic.

 

[dcritzer]

yeah when I was in the military we had an F250 with the same issue. I dont think they ever got it fixed.

 

[Dennis K]

Wobble is not unique to Jeeps. We motorcyclists have been dealing with this forever. Technology has done a lot to mask the phenomenon, but it still occurs. As others have posted, there are a lot of variables but my belief is the shorter wheelbase and weight distribution/balance are the base culprits just waiting for one insignificant thing to upset the apple cart. Youtube has the Dunlop Tire wobble story from the early 70's. Two wheels, not four but the engineering demo is convincing. Many different models shown, they all do it with the right/wrong input.

Had a wobble on my 67 Harley Electric Glide... I-5 in San Diego at 70 mph... Fun times...

 

[ShadowsPapa]

yeah when I was in the military we had an F250 with the same issue. I dont think they ever got it fixed.

My frustration was - I liked that Ford otherwise, it had been good to me, but I spent 2 grand out of pocket for parts and such, and to still have issues. It was time, it was getting older, trucks were getting better, and that issue was getting expensive for a truck that was over 15 years old.
I knew loose parts can be a problem, worn bushings, whatever, so I decided - replace it all, everything, all bushings, all joints.
Things I can't remember - if it had newer tires at the time, or if I checked everything 100% thoroughly for anything being bent that was a non-wear item. Something could have been missed but after 2 grand on a 15+ year old truck........ cut my losses.

 

[Dennis K]

Experienced DW on a test drive 2020 Sport S. Salesman in the back seat turned white. Told him not to worry...
Still ordered my 21 Sport S and am seeing no problems, yet. It does have the updated steering box....

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