Death Wobble Poll

[AnnDee4444]

I have been wondering for a while about the causes of death wobble, and realized that we should probably collect some data to see if any patterns emerge. To keep things simple, I am only interested in what your Jeep did with the stock suspension, stock wheels, and stock tires. No wheel spacers either... I am looking for bone stock vs bone stock comparison.

I have a theory that sidewall flex is the origin of death wobble, and that all other fixes are either replacing worn out parts or upgrading the existing parts to handle the loads better... but none of the fixes actually address the root of the problem. My theory is that the sidewall height and width of a Rubicon K02 mounted on the OEM wheel is much more balloon-like than the OEM Sport tire mounted on the same wheel. Because of this, the Rubicon's tire is more likely to bounce around like an undamped spring. The steering stabilizer tries to compensate for the oscillating mass of rubber, but the undersized shock and bushing flex eventually give in to the wobble.

If my theory is correct, the Sport should have the lowest percentage of factory death wobble. I know this isn't a perfect test though, as caster & spring height is not consistent (drag bar angles would be different).

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[MOTC JL]

I have a 2018 JLU Sport totally stock and got the DW at about 7,000 miles. Took it to the Dealer and they couldn't get it to go so told me to pick it up. I said "I don't think so" as I called another dealer and they told me the steering stabilizer was on the Jeep bulletin and should be replaced with the updated one-it's on BO for a couple more weeks. Now I've been reading about several JL owners having this done to only have the DW come back in a couple thousand miles so not sure if this is just a mask of the real problem going on. We'll see. Pretty bummed since I've been driving XJ's for 25 years with absolutely no problems and this is my first new car and I don't feel safe driving it, especially with my family.

 

[JeepCares]

I have a 2018 JLU Sport totally stock and got the DW at about 7,000 miles. Took it to the Dealer and they couldn't get it to go so told me to pick it up. I said "I don't think so" as I called another dealer and they told me the steering stabilizer was on the Jeep bulletin and should be replaced with the updated one-it's on BO for a couple more weeks. Now I've been reading about several JL owners having this done to only have the DW come back in a couple thousand miles so not sure if this is just a mask of the real problem going on. We'll see. Pretty bummed since I've been driving XJ's for 25 years with absolutely no problems and this is my first new car and I don't feel safe driving it, especially with my family.

Hi MOTC JL,
We understand why this may be disappointing. Please send us a private message if you need to return to the dealer so we can have this documented and provide you with additional assistance while your dealer works on a diagnosis.
Lydia
Jeep Social Care Specialist

 

[ChrispyJL]

Rubicon is more susceptible to DW because it uses the same control arms as the other trims but is 1.5" higher causing the castor to be nowhere near optimal angle, put adjustable arms on and give it more castor will fix it if all you have is DW.
Also the shitty soggy bread bushings they used in the track bar are garbage.

Also, I have heard people with sports who have DW can add the MOPAR lift kit arms to increase castor and it fixes it.

I have an appointment to have my track bar updated to the one with stiffer bushings to see if it helps, as well as the new toe in spec
My JLU Sport S is stock atm

My DW was terrible and started around 3000 miles on OD, I took out my torque wrench and found some loose shit, tightened it up and it helped dramatically, still has some wobble at highway speed if I hit rough road or a bad expansion joint though, but not as bad as before I torqued everything to spec.

DW should have nothing to do with tire sidewall.

If I still experience wobbles, I am going to insist my dealer puts on the control arms from the MOPAR lift kit to add some castor as a test for their knowledge to give FCA feedback.

My theory is the JL in every spec, doesn't have enough castor, now throw in shitty bushings, a POS steering stabilizer and you have what we have now.
the JL sits higher than any wrangler made stock, my Cherokee in comparison needed 7 degrees to fix DW after I lifted it, and sat about as high as the JL does stock.

So IMO it is shitty engineering by people who have no clue about lifted off road jeeps.

 

[AnnDee4444]

Rubicon is more susceptible to DW

Actually, this is what I am trying to figure out. According to the poll, right now the Sport is at 33% with death wobble while the Rubicon is only 16%. I know the sample size is tiny, but it would be interesting if this pattern continues.

my Cherokee in comparison needed 7 degrees to fix DW after I lifted it

The Cherokee was also 7° from the factory:

 

[ChrispyJL]

The Cherokee was also 7° from the factory:

Interesting, so it seems they got the castor # correct from the factory on the XJ, and bringing it back to factory spec fixed it.
Because the XJ didn't have DW from factory, same held true for my TJ, no DW stock, only altering the castor created DW.
Or after the suspension got worn out, but that didn't happen until 10s of thousands of miles.
This is my first jeep that had DW within 3k miles in stock form.
I think the JL wasn't given enough from factory, coupled with cheap parts to maximize profits.
Also I don't know sales numbers, but if they sold more Sports it would make sense that the sport is higher.

Point is, a stock Jeep should not be getting DW after a few thousand miles, and customers should not have to reengineer the damn suspension to fix it, or be told it's a jeep thing, or be told were crazy.
The loose steering and wander is a different issue all together
But it isn't just Jeep, it is every manufacturer, and not only the auto industry, you see crap everywhere, nothing is made with pride anymore.

 

[AnnDee4444]

Interesting, so it seems they got the castor # correct from the factory on the XJ, and bringing it back to factory spec fixed it.

Because the XJ didn't have DW from factory, same held true for my TJ, no DW stock, only altering the castor created DW.
Or after the suspension got worn out, but that didn't happen until 10s of thousands of miles.
This is my first jeep that had DW within 3k miles in stock form.
I think the JL wasn't given enough from factory, coupled with cheap parts to maximize profits.
Also I don't know sales numbers, but if they sold more Sports it would make sense that the sport is higher.

Point is, a stock Jeep should not be getting DW after a few thousand miles, and customers should not have to reengineer the damn suspension to fix it, or be told it's a jeep thing, or be told were crazy.
The loose steering and wander is a different issue all together
But it isn't just Jeep, it is every manufacturer, and not only the auto industry, you see crap everywhere, nothing is made with pride anymore.

I am comparing only Sports against Sports (Rubicons against Rubicons, etc.) so that the sales numbers don't sway the percentages. Example: right now 15 Sports have taken the poll, and 5 have death wobble. That means that 33% of Sports have death wobble, while only 4 out of 30 (13%) of Rubicons have death wobble. This is exactly the opposite of what I expected to see, and I'm not quite sure what to make of it.

As far as the XJ caster, it looks like AMC got it right the first time (which I think was also the first instance of the Quadra-Link front suspension).

For what it's worth, the front Dana 44 (and likely other JL front axles) has 6° built in. That alone should probably dictate that the caster be around 6° for proper driveshaft alignment (assuming the transfer case is at 0°... I haven't measured it).

 

[Spartan99]

DW is like herpes. It’ll never go away completely. The response from the Jeep Care rep is funny. They have no clue what to do about it.

 

[Capt-Zoom]

I have been wondering for a while about the causes of death wobble, and realized that we should probably collect some data to see if any patterns emerge. To keep things simple, I am only interested in what your Jeep did with the stock suspension, stock wheels, and stock tires. No wheel spacers either... I am looking for bone stock vs bone stock comparison.

I have a theory that sidewall flex is the origin of death wobble, and that all other fixes are either replacing worn out parts or upgrading the existing parts to handle the loads better... but none of the fixes actually address the root of the problem. My theory is that the sidewall height and width of a Rubicon K02 mounted on the OEM wheel is much more balloon-like than the OEM Sport tire mounted on the same wheel. Because of this, the Rubicon's tire is more likely to bounce around like an undamped spring. The steering stabilizer tries to compensate for the oscillating mass of rubber, but the undersized shock and bushing flex eventually give in to the wobble.

If my theory is correct, the Sport should have the lowest percentage of factory death wobble. I know this isn't a perfect test though, as caster & spring height is not consistent (drag bar angles would be different).

I doubt sidewall height has much to do with this if so those of us with TJs running 33 and 35 BFG TKO2 inch tires on 15 inch wheels should have massive death wobble since they have an even greater sidewall

Also in the jl the Sahara should have the least sidewall due to its 18 inch wheels.

 

[AnnDee4444]

I doubt sidewall height has much to do with this if so those of us with TJs running 33 and 35 BFG TKO2 inch tires on 15 inch wheels should have massive death wobble since they have an even greater sidewall

Also in the jl the Sahara should have the least sidewall due to its 18 inch wheels.

Yeah, my own poll is proving my theory incorrect. The smallest tire, most caster version is more prone to death wobble than the largest tire with least caster.

Percentage with death wobble (so far):

Sport = 33%
Rubicon = 16%
Sahara/Moab = not enough data at this time​

 

[Hyper]

Just answered the survey above. I own a JKU but rented a 2019 JLU sahara put 2600 miles on it in 8 days I experienced death wobble 3 separate times. I thought it only impacted modified vehicles. Really surprised me!

 

[four low]

I have been wondering for a while about the causes of death wobble, and realized that we should probably collect some data to see if any patterns emerge. To keep things simple, I am only interested in what your Jeep did with the stock suspension, stock wheels, and stock tires. No wheel spacers either... I am looking for bone stock vs bone stock comparison.

I have a theory that sidewall flex is the origin of death wobble, and that all other fixes are either replacing worn out parts or upgrading the existing parts to handle the loads better... but none of the fixes actually address the root of the problem. My theory is that the sidewall height and width of a Rubicon K02 mounted on the OEM wheel is much more balloon-like than the OEM Sport tire mounted on the same wheel. Because of this, the Rubicon's tire is more likely to bounce around like an undamped spring. The steering stabilizer tries to compensate for the oscillating mass of rubber, but the undersized shock and bushing flex eventually give in to the wobble.

If my theory is correct, the Sport should have the lowest percentage of factory death wobble. I know this isn't a perfect test though, as caster & spring height is not consistent (drag bar angles would be different).

Thank you for doing this information -gathering, however, side wall flex,or lack of, isn't the cause of DW. Still, should bring stories to the table, will be interesting to see what the common denominator is.

 

[AnnDee4444]

Just answered the survey above. I own a JKU but rented a 2019 JLU sahara put 2600 miles on it in 8 days I experienced death wobble 3 separate times. I thought it only impacted modified vehicles. Really surprised me!

Thanks for the input!

Thank you for doing this information -gathering, however, side wall flex,or lack of, isn't the cause of DW. Still, should bring stories to the table, will be interesting to see what the common denominator is.

I'm still not convinced that tire profile or sidewall height doesn't have something to do with it. Suspension shocks are used to dampen the coil spring oscillations, and a steering stabilizer is used to dampen the steering oscillations. Something in the front suspension is functioning like a "spring" and is causing oscillations in the steering. To me it seems the obvious culprit is the tire, or some other rubber component. This is totally ignoring the caster differences in the different models, which should be in the Sports favor.

Either way, my own poll is proving my theory totally wrong. Rubicons are consistently polling less than Sports.

Percentage with Death Wobble (as of 6/14):

Sport: 29%
Rubicon: 14%
Sahara/Moab = not enough data at this time​

I wonder if the Rubicon shocks could have an effect...

 

[Simann]

I had a JK with AEV equipment, AEV 3.5" lift on 35" Mastercraft MXT mud terrain tires. I put 78K miles in TWO years (75% highway between 60-90mph). Of course, I rotated tires regularly. The lift was professionally installed at the dealership, aligned it twice a year. Never once did I experience "death wobble." This does not explain the claims of the DW on a STOCK JL, but as for the JK, I think catalyst is multi factorial; new suspension equipment on an older truck, improper alignment and excessive speed with quick steering inputs.

 

[TCogs1]

I am comparing only Sports against Sports (Rubicons against Rubicons, etc.) so that the sales numbers don't sway the percentages. Example: right now 15 Sports have taken the poll, and 5 have death wobble. That means that 33% of Sports have death wobble, while only 4 out of 30 (13%) of Rubicons have death wobble. This is exactly the opposite of what I expected to see, and I'm not quite sure what to make of it.

As far as the XJ caster, it looks like AMC got it right the first time (which I think was also the first instance of the Quadra-Link front suspension).

For what it's worth, the front Dana 44 (and likely other JL front axles) has 6° built in. That alone should probably dictate that the caster be around 6° for proper driveshaft alignment (assuming the transfer case is at 0°... I haven't measured it).

Thanks for the post... I am surprised and often wondered what the JLUR specs were.. Over the years, I always targeted 5 degrees.. I will ask the dealer to show me the alignment results my next trip in.. My DW started at 4k, loose bolts everywhere and a bad damper.. and now it is back at 12k.. we will see what is causing it this time.. I suspect loose ball joints and bad damper..

Thanks again for the post!

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