Jeep Owners…Keep An Eye on This “Death Wobble’ Proposed Settlement

[Sooper Camper]

I've been curious to know more about the ball joints on a JK. I heard they were junk, but the JK's that my wife and I own are recon packages and Jeep claimed they had "upgraded" ball joints on the recon front axle, which is different as well with thicker tubes, brackets and much heavier inner C's. I just wonder what they consider an upgrade?

It's been a while, I don't remember the specifics on what revisions happened over the course of it either. The big flaw (shared with the Ram's) is that only the lower is load bearing, and the upper is a plunging style (The JL was redesigned as a dual load bearing, and the Danas in Ford Super Duty's were dual load bearing). The part that bore the load was a nylon liner, and the preload was done by a small 'finger' washer that preloaded the assembly. Not everyone had a problem, it's easy to conflate 10's of thousands of complaints with a critical flaw in the design, but the reality is they made over 2 million of the things, over half of those were heavily modified, and a huge percentage of those were abused (many by newcomers to the sport)...

TL,dr; moral of the story is anything can death wobble. Solid axles are more prone to it because there is a rigid bar connecting both wheels. The track bar is also the only thing maintaining lateral stability, while the drag link and tie rod make the vehicle turn. if any one of the 6 joints involved in that equation is loose, it creates a feedback loop through the whole system very easily.

 

[FordGuy1]

It's been a while, I don't remember the specifics on what revisions happened over the course of it either. The big flaw (shared with the Ram's) is that only the lower is load bearing, and the upper is a plunging style (The JL was redesigned as a dual load bearing, and the Danas in Ford Super Duty's were dual load bearing). The part that bore the load was a nylon liner, and the preload was done by a small 'finger' washer that preloaded the assembly. Not everyone had a problem, it's easy to conflate 10's of thousands of complaints with a critical flaw in the design, but the reality is they made over 2 million of the things, over half of those were heavily modified, and a huge percentage of those were abused (many by newcomers to the sport)...

TL,dr; moral of the story is anything can death wobble. Solid axles are more prone to it because there is a rigid bar connecting both wheels. The track bar is also the only thing maintaining lateral stability, while the drag link and tie rod make the vehicle turn. if any one of the 6 joints involved in that equation is loose, it creates a feedback loop through the whole system very easily.

Superdutys have the same issue. Jeep does not want to spend the money to put adjustable arms to fix the caster issue. They are looking for the cheapest way out.

 

[Stoffregen Motorsports]

Pardon me for skipping ahead without reading all of the replies, but I feel very strongly on the subject of death wobble, and other related front steering and suspension issues in ALL solid axle trucks. I feel, and have felt this way for a long time, that the problem is a matter of scale. And I feel like new truck and SUV manufacturers share the blame.

How does scale come into play with solid front axles?

I feel that if there were more control over the knuckles, balljoints and tie rod ends would last longer, causing fewer instances of death wobble and other clunks. Control in this case comes in the form of leverage. The vertical distance between the upper and lower balljoints, I feel, is too small on all of the vehicles being sold with solid axles today, at least here in the USA. I feel that if the inner and outer knuckles were bigger and with more distance between the upper and lower balljoints, they would last longer. Same goes for tie rod ends. Longer steering arms and pitman arms would be able to control the mass which exists in large tires. Even stock trucks come with large tires now days, and when those large tires spin up to speed, the inertia created is massive.

The tie rod end issue really boils down to packaging, as there needs to be sufficient clearance between the pivoting axis of the tie rod and the drag link, ie- the steeering box needs to be far enough forward for the two links to "steer clear" of each other (sorry for the pun). Moving the steering box forward means potentially longer frames and decreased approach angles. Balljoints on the other hand could have more distance between them with little effort on the part of manufacturers.

Another way that scale matters is the size of the actual components in the knuckle and tie rod end/steering system. I feel theses components are far too small, with tiny spherical pivots that wear prematurely. This seems like a cost saving effort on the part of the manufacturers, and increasing the size would add cost to the vehicles, say nothing of "planned obsolescence" which may or may not actually exist in the automotive world. Using larger balljoints and tie rod ends on a steering axle could allow the use of more clamping force, which would in turn allow more virtual control over the components.

I have felt that new vehicle manufacturers have missed this issue, or flat out ignored, it for decades. IFS is not the answer. Just give us beefier components.

Note - please excuse me if I used improper terminology. I do not have an engineering degree. My knowledge comes from decades in the business. If anyone agrees with my above statements, and has engineering to back it up, I'd love for you to speak up and help explain.

 

[NatersXJ6]

Pardon me for skipping ahead without reading all of the replies, but I feel very strongly on the subject of death wobble, and other related front steering and suspension issues in ALL solid axle trucks. I feel, and have felt this way for a long time, that the problem is a matter of scale. And I feel like new truck and SUV manufacturers share the blame.

How does scale come into play with solid front axles?

I feel that if there were more control over the knuckles, balljoints and tie rod ends would last longer, causing fewer instances of death wobble and other clunks. Control in this case comes in the form of leverage. The vertical distance between the upper and lower balljoints, I feel, is too small on all of the vehicles being sold with solid axles today, at least here in the USA. I feel that if the inner and outer knuckles were bigger and with more distance between the upper and lower balljoints, they would last longer. Same goes for tie rod ends. Longer steering arms and pitman arms would be able to control the mass which exists in large tires. Even stock trucks come with large tires now days, and when those large tires spin up to speed, the inertia created is massive.

The tie rod end issue really boils down to packaging, as there needs to be sufficient clearance between the pivoting axis of the tie rod and the drag link, ie- the steeering box needs to be far enough forward for the two links to "steer clear" of each other (sorry for the pun). Moving the steering box forward means potentially longer frames and decreased approach angles. Balljoints on the other hand could have more distance between them with little effort on the part of manufacturers.

Another way that scale matters is the size of the actual components in the knuckle and tie rod end/steering system. I feel theses components are far too small, with tiny spherical pivots that wear prematurely. This seems like a cost saving effort on the part of the manufacturers, and increasing the size would add cost to the vehicles, say nothing of "planned obsolescence" which may or may not actually exist in the automotive world. Using larger balljoints and tie rod ends on a steering axle could allow the use of more clamping force, which would in turn allow more virtual control over the components.

I have felt that new vehicle manufacturers have missed this issue, or flat out ignored, it for decades. IFS is not the answer. Just give us beefier components.

Note - please excuse me if I used improper terminology. I do not have an engineering degree. My knowledge comes from decades in the business. If anyone agrees with my above statements, and has engineering to back it up, I'd love for you to speak up and help explain.

I don’t think you’re wrong, but I’m also not sure that a solution in the form of total re-design is needed across all manufacturers. The first assumption would be that engineers designed in a flaw… much more likely that accountants drew a line and engineers accepted a compromise that serves the majority of customers. Only a very small percentage of vehicles are impacted. Obviously it’s a big deal if it is YOUR vehicle. I didn’t love the wobble in my F250, but it was liveable after some basic front end adjustment. I think there are processes in place to deal with the outlier cases, and the “bigger at any cost” crowd has a healthy aftermarket to support them. It’s basically just something interesting to discuss on the internet. Otherwise slow down and watch for bumps while turning!

 

[Stoffregen Motorsports]

I don’t think you’re wrong, but I’m also not sure that a solution in the form of total re-design is needed across all manufacturers. The first assumption would be that engineers designed in a flaw… much more likely that accountants drew a line and engineers accepted a compromise that serves the majority of customers. Only a very small percentage of vehicles are impacted. Obviously it’s a big deal if it is YOUR vehicle. I didn’t love the wobble in my F250, but it was liveable after some basic front end adjustment. I think there are processes in place to deal with the outlier cases, and the “bigger at any cost” crowd has a healthy aftermarket to support them. It’s basically just something interesting to discuss on the internet. Otherwise slow down and watch for bumps while turning!

All true. Yet the basic axle design we use today has been in production since the late 1960s. A redesign wouldn't be out of line after 50 plus years. With larger components, we could have our cake and eat it too.

Another aspect of death wobble that I'm just gonna say it, most people don't understand is wheel offset (or backspacing). Positive offset reduces scrub radius and decreases the amount of leverage the tire has on the steering components. That leverage force, combined with different tire shapes (crown of tread) can cause wobble. Since most of the aftermarket wheels sold have a zero offset or even a negative offset, this is part of the problem. Again, it's packaging. Lots of wheels will interfere with steering arms if the offset is too much on the positive side. Look at almost every single off road and on road race car and you'll find front wheels with positive offset. This is done for a couple reasons, scrub being one of them.

 

[FordGuy1]

I don’t think you’re wrong, but I’m also not sure that a solution in the form of total re-design is needed across all manufacturers. The first assumption would be that engineers designed in a flaw… much more likely that accountants drew a line and engineers accepted a compromise that serves the majority of customers. Only a very small percentage of vehicles are impacted. Obviously it’s a big deal if it is YOUR vehicle. I didn’t love the wobble in my F250, but it was liveable after some basic front end adjustment. I think there are processes in place to deal with the outlier cases, and the “bigger at any cost” crowd has a healthy aftermarket to support them. It’s basically just something interesting to discuss on the internet. Otherwise slow down and watch for bumps while turning!

Superduty death wobble is a very similar issue. Lower the caster a deg or so, and as long as the rest of the front end is tight, 90% of the time it is fixed. Manufactures put as much caster as possible to make a new vehicle steer as light as possible, but as everything breaks in, the wobble starts. Jeeps more of a issue because you cant adjust the caster as easy as you can on a superduty, and on top of it, Jeep does not want to spend the money to replace a set of arms. With labor, Jeep would have a warranty claim around 1k.