Is this the death wobble?

[BajaSportsmobile]

Originally Posted by JoeH

OK, will you agree that this term is most frequently associated with a Quigley 4wd conversion?

Only by some with vested interests perhaps. We have sold dozens of our RIP Kits for Quigley and installed about half of them. I have yet to see a Quigley get the DW's though the owner of one we did last week said he would get them and asked us to diagnose any problems. We replaced a worn Drag Link and his Steering Gear is loose - both potential causes. Our RIP does nothing to "fix" DW's and I have not heard if he still has DW's. I have seen many leaf sprung 4x4's with DW's over the years. The type of spring that holds up the vehicle is not the problem.

[cjken]

My original Quigley (2000) developed death wobble.
It turned out to be associated with the fact that one of the control arms rusted and cracked partially. I ordered new round bars from Quigley.
While I was at it I replaced all of the bushings and tue rod ends.
Was tight after that.

[mgmetalworks]

Here's a good video of a "death wobble" happening to a Super Duty.

https://www.youtube.com/watch?v=8EuQ6f8rgT4

At 1:04 and 1:32 are the really good parts.

It isn't subtle...

[mgmetalworks]

Originally Posted by BajaSportsmobile

"Death Wobble" is when the tires/wheels and steering components move rapidly left to right, right to left, at an uncontrolled rapid rate.

It is steering movement through worn or weak steering or suspension components, initiated by either an uneven surface, out of balance tire/wheel, or impact with something.

The "Death Wobbles" are caused by the self-centering characteristics (Steering Inclination Angle and Caster) of the front suspension and component wear or weakness. When one front tire, say the Right Tire/Wheel, is deflected away from center by hitting a bump, rain groove, tire problem, alignment problem or whatever, it in turn drags through the steering components, the Left Tire/Wheel away from center also. Because there is wear and flex within the steering components (tie rods, tie rod ends, drag links, idler arms, etc.) and suspension components (I-beam bushings, Radius Arm bushings, Ball Joints, etc.) there is a delay between the initiating Right Tire/Wheel and the reacting Left Tire/Wheel. Then, because of self-centering, the Right Tire/Wheel tries to move back to center just before the Left Tire/Wheel tries to move back to center, which because of the above wear and flex, is also being forced back over by the Right Tire/Wheel through the steering components. What happens is that the Right Tire/Wheel and Left Tire/Wheel get out of phase with each other and start a resonance that compounds until both Tire/Wheels are fighting each other and they are oscillating wildly back and forth out of phase. This harmonics will generally only stop when something disrupts it like turning the steering wheel quickly one way, slowing down, slamming on the brakes or even by hitting another bump.

So, the reason that you get so many different recommended fixes for the problem (new I-beam Bushings, new tires, new shocks, re-alignment, etc.) is because that all of them individually or several combined can be the trigger for “DEATH WOBBLES”. My experience has been that incorrect caster and toe settings are the biggest culprit. By incorrect, I do not mean based on the factory settings; those are for stock setup. Once you have lifted or modified the suspension or changed the Tire/Wheels factory setting may not be optimal. New components, being tighter will help to solve the problem, but I have found that more caster is the best solution assuming all good parts. Adding more caster increases the self-centering characteristic and helps to keep the Tire/Wheel tracking true and less likely to deflect away from center. “That same effect is what makes the truck want to go straight down the road at speed b/c each front tire is trying to get to it's lowest (unloaded) position. The lowest position for the left front is at full right turn and vice versa. At some point (hopefully going straight) they reach a balance.”....

I agree with what has been said here. Especially the part about caster and toe.

[deserteagle56]

OK, will you agree that this term is most frequently associated with a Quigley 4wd conversion?[/quote]

Only by some with vested interests perhaps. We have sold dozens of our RIP Kits for Quigley and installed about half of them. I have yet to see a Quigley get the DW's though the owner of one we did last week said he would get them and asked us to diagnose any problems. We replaced a worn Drag Link and his Steering Gear is loose - both potential causes. Our RIP does nothing to "fix" DW's and I have not heard if he still has DW's. I have seen many leaf sprung 4x4's with DW's over the years. The type of spring that holds up the vehicle is not the problem.[/quote]

Had problems with death wobble on my 2007 Quigley after it turned over 30,000 miles. At first it was mild - as someone said above, a quick turn of the steering wheel would stop the shaking. Then a few years ago I was driving in fairly heavy traffic through the Virgin River Canyon on I-15 just south of St George, Utah. As those of you who have driven this section of I-15 know, its a place where you really need to concentrate on your driving. At the time the roadway had some huge potholes and I managed to hit one of them just right. The resulting death wobble scared me half to death - and the traffic around me also, judging by the looks on the faces in the cars that were alongside of me! The violent shaking would not quit until the van was nearly at a stop - twisting the steering wheel back and forth did no good, nor did applying the brakes hard. Luckily the surrounding traffic had backed off and given me plenty of room to recover - or maybe so they could watch me smash into the rock wall or fall off the roadway into the river! I called Quigley and explained what happened - and boy, did they get mad when I called it "death wobble"! Seems they are pretty sensitive about that. But they also knew how to fix the problem. When I gave them the build number of my van they immediately sent out an updated track bar assembly with different style bushings in it. I installed it, and for the last 20,000 miles haven't had a hint of death wobble. The van came from Quigley with LT285/75R17 tires installed on aftermarket wheels and the Quigley tech advised that the bigger tires exacerbate the problem, as does underinflation. So if I air down for off-highway travel I make sure I get the tires back up to at least 50 psi before driving 75 on pavement.

[Pntyrmvr]

Hi,

I believe that I did indeed experience the death wobble. The video posted above proves it to me.

I said the wheel didn't pull me. Not heavily to one side as I expected, but it sure did rattle me around.

The comments listed above also fit perfectly. The front end still had it's 30 years (likely) worth of sloppy worn bits plus the inherent lack of feel that vehicles had back then. The front bearing that I bush repaired hadn't been replaced yet. I did that repair last week and found a lot of slop in that area as the hub damage precluded getting anywhere near the factory torque setting to the retaining nut(s). That slop alone was "feelable" in the wheel.

I also recall the last set of tires on the van when I got it had poor wear patterns indicative of a bad alignment. I have only put 1000 miles on it since I bought it so I can't see any wear on these front tires.

I am now committed to replacing the front spring eye bushings, the ball joints, the alignment bushings, and the steering linkages. I'll then set the front alignment up to factory specs and see how it is.

If that fixes it I'll add a new steering stabilizer in hopes that I don't mask any issues by adding it first.

Thank you for your input team. Priceless advice as usual.

Regards,

Gavin