Wheel hop, axle wrap...

[MoparToYou]

Hey here is a thought. A person could easily make up a slightly longer version of this mount. Say 1 to 1 1/2" longer AND could put different mounting holes in it. See what kind of change you could get. This also makes it look like a person could very easily with out welding to the axle install a V style 4 link and remove the upper control arms and make a real 4 link here. Just throwing it out. I'd personally make a multi position mount and try that too. Being able to bolt to the axle

Now that is an excellent thought nts007. That bracket just bolts onto the axle, so fabbing up a longer bracket with multiple holes in it could allow you to get much more leverage on the shock, and force more shock movement for the same amount of axle movement, thereby doing a better job of damping the movement of the axle. When I'm under my truck installing a second shock I'll measure how much travel there is to the bump stop, and calculate how much longer that bracket could be before it hits anything at full suspension compression. Now I think we're getting somewhere. It would be very easy for an aftermarket company to make a new bolt on shock mounting bracket for these trucks that would stop axle wrap.

[TwinStick]

Logically thinking, it seems as if a 4 link should not/does not have axle wrap by its very design. Are the stock mushy rubber bushings causing this ? If so, then aftermarket solid bushings should theoretically eliminate this, yes ?

Is maybe what we are experiencing just axle hop ? Meaning: the axle/tires are actually getting traction in small bites, then starting to move upwards, then the traction gives way & axle comes back down with a bang ?

Please forgive my non-college educated questions & thoughts if they are completely wrong.

[nts007]

Here is a decent article more on controlling axle wrap.
http://www.4x4wire.com/jeep/tech/susp/axlewrap/

The occurrences that the trucks are getting may be just real bad wheel hop. BUT I don't feel that dodge created a good mounting point for the lower control arms as they seem to be in front of the axle and are in no position to help with axle wrap in any way. They look like their only job is to control forward/rearward movement. So everything leans on the upper arms and it just isn't enough.

How I see it

Axle wrap and wheel hop are solidly linked together in this setup. As the suspension 'wheel hops' in a vertical direction the lower control arms are swinging like this ) and the axle pivots on the upper control arm mount thus the bottom of the axle is rocking back and forth while the wheels hop doubling the issue so you have WHEEL HOP INDUCED AXLE WRAP.

Stiffer shocks are not a real option

My opinion. New mount points below the axle and longer lower control arms.

Even better new mount points below for the lowers and a new V link properly setup to that upper shock mount.

Well let's see some fabbing. Who is gonna take the plunge first and prove to Chrysler engineers that we know more than they do

[Will]

Logically thinking, it seems as if a 4 link should not/does not have axle wrap by its very design. Are the stock mushy rubber bushings causing this ? If so, then aftermarket solid bushings should theoretically eliminate this, yes ?

Is maybe what we are experiencing just axle hop ? Meaning: the axle/tires are actually getting traction in small bites, then starting to move upwards, then the traction gives way & axle comes back down with a bang ?

Please forgive my non-college educated questions & thoughts if they are completely wrong.

This is exactly what I've been saying, its power hopping like a tractor but much faster and they have zero suspension.

[loveracing1988]

I find it interesting that this picture of the Ram 2500 rear suspension shows a plain black painted kicker shock.

A Power Wagon, however, has a yellow Bilstein shock with a blue shock boot in the same position as that plain black shock. So one has to ask them self, "self, is there any difference in damping between the Bilstein kicker shock and the plain black kicker shock?" Also, is Ram using a steering stabilizer shock here, that is very stiff, and damped equally in compression and extension? Or are they just using a generic Bilstein suspension shock, that will typically have far more compression damping than rebound damping. When I get the new shock I'll at least try and see if it has equal damping in both directions, although I'm pretty sure I'm not going to be able to push the shock shaft fast enough in either direction to be able to say.

Based on that picture, it looks like there are basically three ways to decrease axle wrap with this suspension. 1. Change the mounting points of the control arms on the axle, so there is more leverage on the axle to hold it in place, and not let it wrap. 2. Change to control arms that don't have giant 3" diameter soft rubber bushings. 3. improve the function of the anti-wrap shock absorber to try to reduce axle wrap. The first two are complicated and expensive, so I'm going to try #3. These would be separate from any improvements that may come from changes in tire pressure, etc.

Ignore the black shock, all of the 2500's get the bilstein shock.

[TwinStick]

Yeah, that shock may only dampen the mush in the factory rubber bushings, lol.

[Fred]

Just wondering what is going on with my 2012 PW with 28K miles. I installed 35x12.5r17 BFG KO2 tires on new set of rims. Michelin / BFG has replaced all 4 because of wheel hp and shake at several speeds on road. I never had this issue on old compound factory BFG's. Now Michelin in having Kauffman order 4 more for replacement. Is this tire related or suspension in your opinions. By the way Kauffman/Discount Tires/and a local tire company Butler Tire in ATL have all taken a stab at balancing. Butler even did balance on the vehicle. Ideas?

[nts007]

That's really weird. I would say balancing is the first thing to look at. The other could be a blown shock. It would only take one. And the tire just starts bouncing uncontrolled

[adeluca73]

I find it interesting that this picture of the Ram 2500 rear suspension shows a plain black painted kicker shock.

A Power Wagon, however, has a yellow Bilstein shock with a blue shock boot in the same position as that plain black shock. So one has to ask them self, "self, is there any difference in damping between the Bilstein kicker shock and the plain black kicker shock?" Also, is Ram using a steering stabilizer shock here, that is very stiff, and damped equally in compression and extension? Or are they just using a generic Bilstein suspension shock, that will typically have far more compression damping than rebound damping. When I get the new shock I'll at least try and see if it has equal damping in both directions, although I'm pretty sure I'm not going to be able to push the shock shaft fast enough in either direction to be able to say.

Based on that picture, it looks like there are basically three ways to decrease axle wrap with this suspension. 1. Change the mounting points of the control arms on the axle, so there is more leverage on the axle to hold it in place, and not let it wrap. 2. Change to control arms that don't have giant 3" diameter soft rubber bushings. 3. improve the function of the anti-wrap shock absorber to try to reduce axle wrap. The first two are complicated and expensive, so I'm going to try #3. These would be separate from any improvements that may come from changes in tire pressure, etc.

Any updates on playing with adding a 2nd axle dampener?

[MoparToYou]

I just got the shock today. I don't know when I will be able to install it. We got 19" of snow two days ago, and it was -11 F this morning, so everything is frozen solid around here. I need to let the truck thaw out, and some of the ice and snow underneath the truck melt off before I get under there to install the second shock. I am also on call at work for the next week, so I don't want to get in the middle of something and get called in. I think the weekend after this weekend will be the first I get a chance to try installing it.

[waldo]

Weight in the bed will help a lot. I haven't had the problem like some here in snow, but I think it is because I always keep a lot of weight in my tool box in the bed. I figured that the new model would have improved, to bad that is sounds like it hasn't especially since the bed capacity is so much less.

My 2016 is worse than the 07 with leaf springs.

I'm taking it back when I get home.

[TwinStick]

Do Jeep Rubicons have this issue stock ???

Do Ford Rapturds have this issue stock ???

They also have a flexy suspension. Just curious.

[adeluca73]

Weight in the bed will help a lot. I haven't had the problem like some here in snow, but I think it is because I always keep a lot of weight in my tool box in the bed. I figured that the new model would have improved, to bad that is sounds like it hasn't especially since the bed capacity is so much less.

My 2016 is worse than the 07 with leaf springs.

I'm taking it back when I get home.

Taking what back???

[olyelr]

Do Jeep Rubicons have this issue stock ???

Do Ford Rapturds have this issue stock ???

They also have a flexy suspension. Just curious.

Yep, the jeeps do for sure. I can vouch for that.

And again, with the full link suspension i believe it is more of a hop thing, not wrap.

[MoparToYou]

A stock Rubicon does do an axle hop thing when spinning the tires on loose terrain. But it is much much more subdued than the axle hop that the Power Wagon does. It feels softer and slower than the Power Wagon hop, which in comparison feels like it is going to shake the truck apart. If we were only dealing with the amount of hop that a Rubicon has, I wouldn't be complaining about it.

[olyelr]

A stock Rubicon does do an axle hop thing when spinning the tires on loose terrain. But it is much much more subdued than the axle hop that the Power Wagon does. It feels softer and slower than the Power Wagon hop, which in comparison feels like it is going to shake the truck apart. If we were only dealing with the amount of hop that a Rubicon has, I wouldn't be complaining about it.

I have had my Rubicon hopping so bad I knew the damn axles and suspension were gonna rip right out from under it (snow wheeling). I can not imagine it could possibly get any worse with the PW than what I have experienced in my Jeep (that was with the stock suspension anyway).

But, with the added weight of the PW, I bet the hop can get worse much easier.

[TwinStick]

I have experienced the wicked hop---I thought something was gonna break for sure. I had to get into my back yard to get the tilt bed trailer when the snowblower broke during a 2 week long series of snow storms (before i had ramps). There was about 3-4' of hard packed snowblown snow, about 35'-45' long. It was hoping & banging so loud, 2 of my neighbors came out. I was in 4Lo 1st gear. I think they thought i broke my new truck & was gonna bust my balls. They said no way no how was i gonna make it into my back yard. I backed up, locked both lockers & hit it in 3rd gear & pinned it. I made it---with such force I had to mash the brakes to keep from hitting my shed !!! LOL Hooked up the trailer & drove back out with no issues. Then i asked them if they think their Ford Ranger or Chevy 1500 could have done that ? They both said Nope at the same time.
My hop was much worse with sway bar dis connected vs when it was not.

[waldo]

I've posted on this topic in another thread. I know it's a sort of "hot and passionate" issue, because, let's face it, once that rear end starts getting jittery and shaking your teeth out of your head, it sucks, and we all want to wring our fists at the driveline eng. team for being out-of-touch and obtuse with how "us", the customers, use these trucks, not to know this is an issue, right?

But I promise you, that center shock dampens the issue of rear end hop/wrap. I have a PhD in Aerospace engineering, and am a professor at the AF Institute of Technology, and one of the courses I teach is the Theory of Vibrations, and Vibration Damping & Control. The center shock is a damper, it affects the Dynamic Equation of Motion by changing the dampening term (C) which retards velocity, in this case, it's the velocity of the unsprung mass in the rear end. It's biggest effect from my estimation, is it alters the resonance point, and changes the natural frequency of the oscillatory response. Dynamic systems are excited by external forces, either by an onset of an initial condition (an predetermined displacement or an impulse, or by the application of a periodic applied external force), here we are experiencing the application of a periodically applied external force, generated by the mass of the sprung weight, the surface condition, and the forward velocity. That center dampener will alter the systems' resonance point (by changing the system's overall material properties) and hopefully will move the wrap/hop outside of a predetermined vibration profile, which I assume the drivetrain engineers determined by conducting extensive off-road instrumented tests by outfitting trucks with accelerometers and strain gauges and then driving over various terrain at various velocities using different suspension settings, reducing the data with a Spectrum Analyzer, determining a system Frequency Response Function (FRF), and then designing the center shock to move the system response to be outside of the collected data. Is it a bandaid--yeah, you could look at that way, but remember, the previous rear suspensions were leafs with opposing shocks, the new suspensions are the coil link spring deals, so the center shock was an integrally designed component from the start.

My humble opinion of course....

That's all well and good. Too bad it doesn't work and the rear wheel hop/axle wrap is worse in the snow on the 16's than the 3G leaf spring trucks. My wife's Escape would have come up this mountain Tuesday with less drama than this truck. Same for the 07 PW I have.

[Will]

Just find a spot where it will do it and stay it until it breaks, then take it to the dealer and say see wtf I'm talking about!?

[nts007]

Wife's grand Cherokee is the same. No fuss playing in deep snow. No wheel hop or axle wrap issues. And it's coil springs all around. But it had a 3link rear. And it works very well. My 08 isn't bad with pw leafs. My 06 would hop a bit. Little bit of power always fixed it. But nothing compared to what you guys are experiencing with the new rear ends. It's a little sad. While it works for the half ton crowd and a bunch of the 3/4 tons, why doesn't the 1ton have it if it's so great. Or the cab chassis. They still have leaves. The pw should have stayed with leaves too. Maybe an improved lead pack

[MoparToYou]

Any updates on playing with adding a 2nd axle dampener?

I removed the stock axle dampener Friday, and took measurements of the bolts I would need, and the spacer to go in the center of each shock mount, then spent some time trying to find the parts. The local hardware store had a whole selection of spacers, but not quite big enough for what I needed. The bolt for the shock is an M-14, which is ~ 9/16ths. The biggest spacer they had was 1/2". After a trip to Fastenal, and hours spent online looking for spacers I found these.

https://www.grainger.com/product/GRAING ... ?$smthumb$

A bag of ten would be enough to do the job, ... but, ... $119 for ten spacers! I thought about that for a moment, and remembered that another shock for this application cost $118. If I run triple shocks, instead of duals, I won't need the spacers for the center of the bracket, I can just leave the original shock in the center, and add another shock on each side. All I need for that alteration is two longer M-14 bolts, which I ordered at Fastenal for $6.50 each. The bolts will be here tomorrow and the additional shock by the end of the week.

And on another note, I drove the truck about 230 miles this weekend towing an 18' auto transport trailer with a UTV on it, and without the dampener shock on the truck. For the first 3/4 of the trip I couldn't figure out what was different with the truck. Whenever there was a load on the truck, such as pulling on level ground at 80 mph, or uphill pulling, it felt like the road was rougher than normal. I have driven this section of highway countless times, and it was clearly different this time. I thought I had several out of balance tires on the truck, or perhaps on the trailer, because there was a new "hop" that had not been there before. Then it dawned on me that I had the axle dampener shock off my truck. I decided that Ram doesn't really care if these trucks hop when off road in snow or sand. I think they put the axle dampener shock on because of this tendency to "hop" while under load on the highway if the shock isn't there. Someone else needs to take that axle dampener shock off their truck, and tow something on a highway that they know really well, and see if they notice a difference as well.

[nts007]

But then it stands to question why doesn't the diesel get the dampener.

[Reloaderguy]

Pure Performance makes rear control arms if you want to eliminate the large rubber isolators.

[nts007]

Pure Performance makes rear control arms if you want to eliminate the large rubber isolators.

Now that could defiantly help

[nts007]

I just double checked and it seems only for the 1500s they have rear control arms.

Never mind they are available in the 4.5" full on kits. I didn't see them separate though