Will the PowerWagon have problems with DW because of the taller stance and bigger tir

[PHeadings]

Will the PowerWagon have problems with DW because of the taller stance and bigger tires? Sway bar dropped? Whats camber adjustment set at? Maybe the presents of this new truck will help resolve the DW issue.

 

[Tim]

No, because they know how to set the caster correctly. There is no reason for any truck that is properly aligned and doesn't have worn out balljoints to have death wobble.

 

[brods]

No, because they know how to set the caster correctly. There is no reason for any truck that is properly aligned and doesn't have worn out balljoints to have death wobble.

Please explain how taller tires change caster. Wouldn't scrub radius be more of an issue?

 

[nickleinonen]

Please explain how taller tires change caster. Wouldn't scrub radius be more of an issue?

they don't, but caster is what controls the death wobble... the factory settings are probably too low [closer to 0° than desired] to maintain easy steering at slow speeds, but it can begin to wobble the wheels at higher speeds... camber does not really effect death wobble, toe does not really effect death wobble, the sway bar might, but camber is the most probable cause... an extra degree would help out a lot in very much reducing the death wobble from happening, and caster is the one alignment that least effects tire wear [next to no effect]



camber is non adjustable on our trucks anyways... unless you want to get on the axle with a 50t press & camber jig and start bending the axle...

 

[willysrule]

I agree with most of what nickeinonen said... here is a few more tips...



your steering linkage being at the correct angles makes a big difference with DW also... the track bar has some affect also...



a good "rule of thumb" is that the track bar should be droped to +/- 5* of the stock angle... same with the steering linkage, this is not always possible, but a good start...



I'm sure they corrected all that from the factory with the power wagon... plus it's not like it's lifted 4" or anything...

 

[brods]

An easy way to end the speculation is to look up the factory alignment specs on the 2500 and PW to see if the caster and or toe are any different. My manual hasn’t arrived yet or I’d do it. Also don’t forget to check for any rim offset difference between the stock 2500 and the special PW wheels. Wheel offset would affect scrub radius and could be used to adjust for a taller tire.

they don't, but caster is what controls the death wobble

I have to disagree with that blanket statement. The entire front suspension, from the tires, air pressure, balance, tire and wheel run-out, wheel offset, shocks, bushings, alignment settings, steering geometry, to worn, bent or sloppy components, etc. all have a part in DW. Yes, some of the settings you cannot adjust, like camber and SAI, but that doesn’t mean they don’t matter. Unfortunately there is no magic bullet when it comes to DW. I’m no expert, but I have looked into DW a bit and caster is not the only cause or cure.

 

[PHeadings]

Why yes you can adjust the camber on the dodge stright axle. It's on the lower control arm where it mounts to the axle.

 

[Greg Boardman-RIP]

Cali,

The point where you are talking about is the caster adjustment. On the PW it is the same. The shock towers are the same, the spring buckets are the same, the axle is the same, pitman arm, trak bar, and most everything else is the same. The Anti-Swaybar is very different though. I have seen trucks with 20 miles on them have death wobble, bad ball joints, bad tie rod ends, bad shocks..... All of these things occure with death wobble. Lifting a truck 2. 5 inches like the PW is, will not cause DW. But a bad tie rod end will send you into basketballing tire mode in seconds. Change to a better tire and it will go away. Wear out that tire and it comes back. Change axles, tie rods, trak bars, steering boxes and on and on. Nothing really causes DW, at least that is what DC says. Nothing really cures it either. Thats what DRC says. Your truck either gets it or it doesen't. Some do, most don't. I am sure the PW will have the same track record with DW.

Greg

 

[BHolm]

I would also question whether caster has much effect on the DW. My MB trucks are solid front axle and the new versions were developing the DW early on, around the time of the MB DC merger, maybe DC sold the rights for it to MB :-laf Anyway, the DW was more prevalent on stock hieght trucks and seems to be related to loose front wheel bearings in the case of the MB trucks. I have two lifted versions, one almost four inches, the other around 2-2. 5". There is no caster adjustment for these trucks and I know I lost a lot of caster in the lift, then I fitted 35" tires. I have had no DW in the lifted trucks. I think loose, worn components up front are more likely the cause than a suspension adjustment. I did lose straightline tracking with the loss of caster but as long as I keep the steering damper in good shape and the wheel bearings are not loose, I don't expect the DW to surfacce.



On the PW, we are not talking BIG tires, they are 285's like I already run on two trucks. Lots of guys are running bigger yet. As mentioned the lift is minor as well. I bet it less of a problem on the PW because the Hemi is a lightwieght compared to the Cummins and the extra wieght certainly seems to contribute to front end parts wear, which I am more likely to associate with the DW.

 

[Tim]

Loose front wheel bearings I'd believe, or loose balljoints. The swaybar is not there to control death wobble, you can remove it completely and your truck should drive the same, minus some extra body roll in turns.



Bigger tires exaggerate what happens under normal conditions until the occilation is such that we call it, "Death wobble. "



99. 9% of death wobble cases can be solved by one of two things. Increase your caster ever so slightly. The other is to toe your tires in a little more, about 1/8". When big, wide tires go down the road they will tend to pull themselves straight and it will help control the wobble. Don't do it too much as toe can affect tire wear.



I can't believe this is such a widely misunderstood concept. Those of us in the rest of the 4wd world have experienced this for a long time running big tires down the road to wherever we're going four wheeling.

 

[Greg Boardman-RIP]

I agree with Tim,

The anti-swaybar is not the effective cure for DW. I don't even have a anti-swaybar on my truck. A little more bodyroll is all the effect I have. Caster is usually the cause for DW and a small adjustment is all the cure needed.



Tim,

Most of the people out in truck world that have expierenced DW on their trucks have never even heard of it before. The TDR is a place where it is addressed on a constant. Guys can come here and search for answers. I have been answering questions about DW on 03-05 trucks for years and I still get calls daily about help that is needed. I don't believe that our suspension cures DW and I don't believe it causes it either. Partial part failure is the key to DW. Finding out what part has failed is the cure.

Greg

 

[brods]

Bigger tires exaggerate what happens under normal conditions until the occilation is such that we call it, "Death wobble. "

Yes agreed. Bigger tires also change the geometry of the front suspension as well.

99. 9% of death wobble cases can be solved by one of two things. Increase your caster ever so slightly. The other is to toe your tires in a little more, about 1/8". When big, wide tires go down the road they will tend to pull themselves straight and it will help control the wobble. Don't do it too much as toe can affect tire wear.



I can't believe this is such a widely misunderstood concept. Those of us in the rest of the 4wd world have experienced this for a long time running big tires down the road to wherever we're going four wheeling.

Did you really need to add that last part? So I guess I’m just a little slow if its clear to all the “old timers” running big tires down the road for sooo long, right?



99. 9%? So only 1 guy out of every 1000 with DW has worn components or something else as a cause? Seems unlikely.



Ok, have patience with me now, DW is caused by not enough caster, caster, caster, caster, and now toe…. . …but. . um…wait a minute. Toe is not caster is it? Why does changing the toe do anything? Could it have something to do with scrub radius? And isn’t scrub radius a function of steering axis inclination (SAI), tire height, wheel width and offset?



So, assuming the caster / toe change “fixes” the DW in this case, then the “cause” is the change in scrub radius due to different size tires and/or wheels, no? And the bandaid in this one case is to add more caster and tweak the toe, yes?





DW has been around for ages and there are plenty of posts about it on Jeep and GM sites too. Over 3 years ago I talked to BFG tires, Dana (Traction Tech Division), ProComp tires, Interco tires, Skyjacker, emailed Rancho, and others as well as doing searches on the web and checking factory manuals. The more I learned about DW the more I realize how complex the causes can be.



Here is a reply from Rancho:

Thank you for your interest in Rancho products. Probably the biggest cause

of violent front shimmy other than a problem with the balance or roundness

of the tires and wheels or worn components is not enough positive caster.

This situation can be made worse if the truck is lifted and the front axle

is rotated with shims to lessen the front pinion angle to help straighten

the front driveline. In addition, this angle is not usually adjusted when

aligning a stock vehicle so may not be corrected if the truck is aligned by

someone not familiar with these vehicles and often the alignment is not

checked after lifting straight axle trucks.

Note the words OTHER THAN. That means tire balance and roundness are the number one reasons for DW in Rancho’s opinion.



Various texts on alignment list the following possible causes of front end shimmy:



Wheel and Tire Assembly Lack of Dynamic Balance

Wheel and Tire Assembly Runout (Lateral)

Incorrect Caster (too much or too little positive caster)

Incorrect Toe

Defective / Worn Suspension or Steering Components

Worn Tires

Under or Over Inflated Tires

Excessively Loose Wheel Bearings

Steering Gear Loose



There is a lot more, but this post is already too long.