In depth Death Wobble tech
 
 
 
 
 
Death Wobble. An explanation.

                Death Wobble is violent uncontrolled oscillation of the front wheels. It is mostly induced by opposing caster forces, skid-bouncing the tires, quickly side to side. It can be very tricky to fix if you are not very familiar with what is actually causing it. There are different levels of intensity, ranging from 2 seconds of violent shaking, to non-stop, uncontrolled, whole vehicle vibration, that won't stop until the vehicle stops. Either way, it is called "DEATH wobble" for a reason. You'll know it's Death Wobble if you experience it. If your truck is vibrating a little all the time, being slightly annoying, this is NOT Death Wobble. When Death Wobble happens, your heart rate elevates, you are afraid, and it is very intense. I have experienced Death Wobble in many vehicles, from a brand new Dodge Ram, to a 1964 Lincoln Continental. It's normal reason for happening, on most vehicles, is when suspension and steering parts are very worn out. On these Dodge Rams, even when the truck is almost brand new, poorly designed parts are also big players. Don't fall prey to bad internet intel. We'll do our best to steer you straight here, in regard to the Dodge Rams, and what is going on with Death Wobble(DW from here on out).



Most common causes of Death Wobble, on the Dodge Ram platform, in order of importance. 


#1

TRACKBAR ISSUES

           Problems with the trackbar is the most common reason DW happens on these trucks. As small as 1/16" of side-to-side deflection, can play a part in DW. Rubber/soft bushings, and exaggerated bends in the trackbar design, are the 2 biggest reasons we feel upgrading the trackbar on 2003-2013 Rams, is basically mandatory. Installing 2 piece soft Polyurethane bushings in the stock trackbar is no help, and can almost end up performing worse, after the first week of driving. Even if the bushing ends of the factory trackbar WERE made solid, that still does not address the flexy OEM bar shape, which ends up acting like a big spring. The OEM trackbar as a whole, is just a bad design.

          To clarify the track bar's importance, if you remove the trackbar, you can't even get out of your driveway. Back to the spring analogy....  This is where the design of the trackbar, as a whole, plays a huge part. Here is why.... The trackbar is THE ONLY support for the steering. As you steer left, you compress the trackbar. Steer right, stretch the trackbar. If the trackbar is allowed to compress and extend, the truck can basically steer itself when you encounter forces at the wheel, which can turn into DW oscillations. This is why death-gripping your steering wheel when you get DW, almost makes it worse, as you are HELPING the truck have a mind of it's own. This is why we say the trackbar design, as a whole, must be as solid and rigid as possible. This makes the truck stay on track, and inputs you make through the steering wheel, will actually get to the wheels!

Here is the more in depth explanation of what is actually happening, in regards to the trackbar playing a part of DW, when DW happens in it's most common form. 

  1.  You hit a sharp bump on one side of the truck, or even more common an angled bridge crossing or something, where one tire hits the bump RIGHT before the opposite side of the truck does.
  2. This sharp bump(or two) flexes the trackbar, and as the trackbar releases the bound up force, it kicks back and the tires simulate a turning force. This starts the oscillation, as the quick turn force kick makes tire quickly skid sideways(yes white tire smoke is normal when DW happens) , then it bounces back the other way. The weight of the truck is now basically bouncing on the caster forces, left-right-left-right.......  This is also why TOO much caster can make the DW worse, as the caster force/bounce can over ride the steering damper easier.

2013+ Ram "radius arm platform" track bar notes.

          Dodge improved the trackbar quite a bit, on this new platform, but it's still not perfect. The bends have been relaxed so the bar is less "springy", and the rubber bushings have been improved by having less deflection. Still, with std rubber torsion bushings, it's only a matter of time before they do go soft or fail. I estimate that approximately around 20,000 miles, you will want to plan on upgrading the front trackbar, especially if having increased suspension travel and a bit of lift.



#2

STEERING DAMPER SHOCK

          I used to believe a long time ago, that you did not NEED a steering damper, on any vehicle really. I felt all it really did was help to keep the steering wheel from being jerked out of your hands, and that was it's main purpose. I changed my thinking, when I started specializing in these very heavy Diesel trucks over a decade ago. Here is why you NEED a steering damper, and why you need a really good, proven one.

          It's really simple. Lets go back to the reason for most DW above... Caster forces bouncing side to side. If you kill these caster bouncing forces, you kill DW. A good steering damper can kill the opposing caster forces, before they really begin to amplify, and get overpowering. The key is killing the forces early.

Steering damper location

       I feel the steering damper MUST be on the axle direct mounted to the tie rod. If you've added an upper damper also, try to make the better quality damper on the axle. I would never suggest running ONLY an upper damper at the gearbox/drag link, without a lower damper on the axle. Reason being, this lets flex and slop in the trackbar still cause issue. A steering damper at the drag link only, is no different than say gripping the steering wheel harder, which does zero for irregular handling issues and DW.

Steering damper design, and understanding it.

There are a lot of trusted brands out there producing steering dampers, but they are often very lacking, in actual effectiveness.

  • On the bad list is..... The std Bilstein 5100, cheap Rancho/Skyjacker/etc single and dual damper kits, lower end aluminum Fox unit, and any even high end brand(King/Fox/etc) non-IFP(emulsion) shocks.
  • On the good list....... The Fox 2.0 steel IFP, and Bilstein 7100 IFP, both with the external schrader valve to adjust pressure, are great. Also, surprisingly the OEM Mopar damper from about 2008 up are good too, usually.

This OEM damper being actually good, makes it a common unknowing mistake to try and upgrade the steering damper, so you throw on a Bilstein 5100 thinking you are, but you are generally making the integrity of the front end/handling worse.

  • IFP stands for, "Internal Floating Piston" - This piston separates the damping oil and the air, making it so the oil can provide proper damping qualities. This IFP is creating a separate air reservoir, which is MANDATORY on a steering damper. With a steering damper being laid on it's side, if an emulsion style(air and oil mixed) shock is used, the damping piston will be sitting in a big pocket of air. I'm really not sure why some companies sell emulsion shocks as steering dampers, but they do. Just be smart about it, and aware.
  • IFP and the Nitrogen pressure used - With adjustable pressure IFP dampers, you must use 100psi MINIMUM, for the damper to function properly. This is really important. With less than 100psi pressure, the steering forces can over-ride the Nitrogen pressure, and make the damper cavitate almost helping the truck go into DW. If you are running less than 100psi in your high end IFP steering damper, it is basically doing nothing for you.
  • Bushing ends vs. solid/bearing/uniball ends.... In regards to steering dampers, the best units will always use a design, with an actual solid bearing on the end. The steering damper needs to be able to counter steering force instantly, and bushing ends give just a little bit of deflection.

 


#3

TIRES

         Tires can play a massive roll in DW. I really don't have a true answer for why, only educated guesses. I tried to ignore this as a possible player at first, but tires have been THE problem so many times, I could not ignore it any more. Basically these heavy Dodge Ram's just don't like some tires. Most notable in the BAD category, are BFG A/T tires. While these tires get GREAT tread life, and look great, these heavy trucks often just want to spit them out. I have tried EVERYTHING with some trucks having BFG's, and the truck always feels like it's going to go into DW any second. Then last straw you throw on good Toyo Tires or something, and the truck handles better than ever and the DW is LONG GONE. If I had to choose a tire brand to run, Toyo is hands down #1, and I would say Nitto #2. Unfortunately I have to say stay away front BFG tires on these trucks. The 37" BFG tires have worked well for many though. Just a tough call.

My guess as to why some tires don't work well, is that the tire construction and profile can cause an extra strong bounce force. My thinking is that the stored force when you hit a bump, with some tires like BFG's, can recoil and over-ride the front end/steering damper/ etc. Again, just my guess, as it seems to always be more "square" profile tires, which in regard to design could kick harder, as the more straight sidewall would snap back with more force to the ground.



#4

ALIGNMENT, NORMAL COMPONENT WEAR, AND THE OTHER LITTLE THINGS

            Believe it or not, things like the front end alignment, tie rod ends being a little loose, gearbox a little sloppy, and ball joints with a little vertical play, really don't play that big of a part in DW. Let me clarify....... That's not to say that with EVERYTHING in the front end worn out, and a terrible alignment, that fixing everything won't fix the DW. But, if most front end parts are considered in-spec, and maybe one tie rod end a little extra worn, replacing that one tie rod end alone won't kill the DW. The handling may feel better, and maybe even stop DW for a week or so, but it's still hovering right below the surface. Collectively many small issues CAN add up to the cause of DW, but simply adjusting the alignment, one loose ball joint, or one loose tie rod end alone, is not the cause. Trackbar, steering damper, and good proven tires are where to focus first.