Wheel hop, axle wrap...

[olyelr]

I can remember my 06 3/4 ton Dodge having issues with wheel hop, and by reading on here it sounds like the power wagons are known for it as well. My question is has the rear linked suspension on the 14's and 15's alleviated most of this, or is there still an issue. By design I would think the linked suspension would have pretty much eliminated most of it, but I know my JK can do it in certain scenarios too, so... can anyone elaborate with first hand experience?

[Skyd Ram]

I can remember my 06 3/4 ton Dodge having issues with wheel hop, and by reading on here it sounds like the power wagons are known for it as well. My question is has the rear linked suspension on the 14's and 15's alleviated most of this, or is there still an issue. By design I would think the linked suspension would have pretty much eliminated most of it, but I know my JK can do it in certain scenarios too, so... can anyone elaborate with first hand experience?

Even with the complicated rear suspension on the '14+ trucks they managed to make the wheel hop even worse.

I have a '14 2500 Cummins that will get stuck in sand backing up a 10 degree grade. The new PW's add an axle control shock although I am not sure how well it works personally.

[jeep_boy02]

I see that shock as red flag to a poor link design. A properly linked rearend would not have that.

[olyelr]

I can remember my 06 3/4 ton Dodge having issues with wheel hop, and by reading on here it sounds like the power wagons are known for it as well. My question is has the rear linked suspension on the 14's and 15's alleviated most of this, or is there still an issue. By design I would think the linked suspension would have pretty much eliminated most of it, but I know my JK can do it in certain scenarios too, so... can anyone elaborate with first hand experience?

Even with the complicated rear suspension on the '14+ trucks they managed to make the wheel hop even worse.

I have a '14 2500 Cummins that will get stuck in sand backing up a 10 degree grade. The new PW's add an axle control shock although I am not sure how well it works personally.

Well what the ef. That isn't what I wanted to hear

Whats this shock you guys are talking about? I have never looked under one before.

[Skyd Ram]

I can remember my 06 3/4 ton Dodge having issues with wheel hop, and by reading on here it sounds like the power wagons are known for it as well. My question is has the rear linked suspension on the 14's and 15's alleviated most of this, or is there still an issue. By design I would think the linked suspension would have pretty much eliminated most of it, but I know my JK can do it in certain scenarios too, so... can anyone elaborate with first hand experience?

Even with the complicated rear suspension on the '14+ trucks they managed to make the wheel hop even worse.

I have a '14 2500 Cummins that will get stuck in sand backing up a 10 degree grade. The new PW's add an axle control shock although I am not sure how well it works personally.

Well what the ef. That isn't what I wanted to hear

Whats this shock you guys are talking about? I have never looked under one before.

It's the center shock located at the top of the pumpkin. For some reason I haven't seen one on a Diesel but a lot of the Hemi 2500's have them for some reason.

[JBM Power Wagon]

So far my 2014 has had less wheel hop than my 2011 did. But I have yet to take the 2014 in deep, dense snow. That is where I used to get the worst wheel hop in my 2011.

[MOPARManiac]

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.

[olyelr]

I am no engineer or fabricator, but I have been around suspensions enough... that shock should not do much of anything the way I see it. Looks more like something that will serve the purpose of a traction bar or torque arm, yet its a shock. If the control arm bushings are allowing enough movement for that shock to move much, something ain't right.

I would like to see a gopro video of that rear suspension under a serious workout.

[olyelr]

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.

I think that a lot of wheel hop is from shocks not being stiff enough to dampen the up/down travel, especially with linked suspensions (as apposed to the axle wrapping back and forth with leaf springs). And in that case added weight may help.

[olyelr]

So far my 2014 has had less wheel hop than my 2011 did. But I have yet to take the 2014 in deep, dense snow. That is where I used to get the worst wheel hop in my 2011.

The snow is where I have noticed it most in my Jeep. I have experienced it in the sand dunes with the Jeep though too.

[adeluca73]

The rear axle hop is very minimal if at all noticeable. I had mine in some 24" + deep snow in the woods hunting traveling fire break trails & the rear end was solid, no hop. I wrote an engineering explanation about leafs vs spring rear ends, read it if you're interested in knowing more about the mechanics, equations of motion, & the vibration analysis of why the springs with that center shock help keep the axle from warping.

[olyelr]

The rear axle hop is very minimal if at all noticeable. I had mine in some 24" + deep snow in the woods hunting traveling fire break trails & the rear end was solid, no hop. I wrote an engineering explanation about leafs vs spring rear ends, read it if you're interested in knowing more about the mechanics, equations of motion, & the vibration analysis of why the springs with that center shock help keep the axle from warping.

Got a link to it? I would love to read it.

I know that leafs can allow the axle to twist forward or back during acceleration and braking etc., but how can a linked suspension allow the axle to twist forward or backward at all? And if the axle can not rotate back or forth, what good is that added shock? If it is just for up and down motion of the axle, why not mount it in a more vertical position like the other two?

I can not imagine the engineers would waste a bunch of money to add a shock that does nothing, but I just don't see what it does. Learn me!

[Skyd Ram]

The rear axle hop is very minimal if at all noticeable. I had mine in some 24" + deep snow in the woods hunting traveling fire break trails & the rear end was solid, no hop. I wrote an engineering explanation about leafs vs spring rear ends, read it if you're interested in knowing more about the mechanics, equations of motion, & the vibration analysis of why the springs with that center shock help keep the axle from warping.

Got a link to it? I would love to read it.

I know that leafs can allow the axle to twist forward or back during acceleration and braking etc., but how can a linked suspension allow the axle to twist forward or backward at all? And if the axle can not rotate back or forth, what good is that added shock? If it is just for up and down motion of the axle, why not mount it in a more vertical position like the other two?

I can not imagine the engineers would waste a bunch of money to add a shock that does nothing, but I just don't see what it does. Learn me!

In the case of the Ram rear end they use some pretty big rubber bushings that have a lot of deflection. This deflection will get worse as the bushings start to break down.

The other issues is the actual geometry that they used. The separation between the upper and lower link attachment points at the axle aren't very far apart. The further apart they are the more wrap control they can have n the axle. Also look at where the lower arm is attached. As opposed to the mount being 3-5" below the axle centerline it is actually out in front of the axle itself. That makes the upper arm do all of the work when it comes to controlling the axle wrap. I'm sure that the single horizontal shock controls the wheel hop to an extent but I can't figure out why they don't use it on the Diesel trucks. The only thing that I can think of is that with the added TQ of the Diesel the shock quickly became overwhelmed so they just chose not to bother installing one.

[2wagons1driveway]

Air down boys. Helps so much it's not even funny-"soft springs" "tall gears" 400horsepower" all contribute to axle wrapping shit up!


Sent from somewhere your not

[Will]

I have axle hop in sand even aired down, I'm hoping new shocks will stop it. I dont think I'm having axle "wrap", I think it's more of hopping due to worn out shocks and the fact I've experienced the front axle doing the same thing. I can see the center shock on the illustration above working more has a hopping dampener, it will extend and compress as the entire axle moves up and down, the link system shouldn't allow enough wrap to be an issue. We will see whn I get the new shocks on it that solves it.

[RamGentry]

hmm...I really havent noticed this in my '10. Stock suspension w/ 35s. I had a 2001 mustang cobra and the wheel hop in that thing from a launch and shifting into 2nd was tooth jarring. I havent noticed anything close to that in the truck.

[Will]

This happens when I get in this sugar sand we have in Florida. It's a fast shake shit off the dash bounce until I left off which is immediately. Then I have to back up or something

[usmc369]

Ive never experienced it yet in either snow or sand when aired down to 20-25 psi. Ive climbed many dunes in the outer banks.

[loveracing1988]

I can remember my 06 3/4 ton Dodge having issues with wheel hop, and by reading on here it sounds like the power wagons are known for it as well. My question is has the rear linked suspension on the 14's and 15's alleviated most of this, or is there still an issue. By design I would think the linked suspension would have pretty much eliminated most of it, but I know my JK can do it in certain scenarios too, so... can anyone elaborate with first hand experience?

Even with the complicated rear suspension on the '14+ trucks they managed to make the wheel hop even worse.

I have a '14 2500 Cummins that will get stuck in sand backing up a 10 degree grade. The new PW's add an axle control shock although I am not sure how well it works personally.

Ok, no diesel gets the center shock. The crew cab 6'4 box hemi's get it, possibly the regular cabs too. The crew cab long box trucks and mega cab trucks do not get it either. The length of the drive line has a lot to do with it.
A lot of people are apprehensive about it because it seems like an afterthought to fix a issue ram engineers didn't know they would have. To be honest those people are kind of right, I know when we first started making those axles they did not have that center shock mount in the housing.

[nts007]

As skyd pointed out though, what would have been so hard to fix the geometry giving the control arms more 'actual' control. Look at how the 3-4 link rock crawler buggies are setup. This just seems like Chrysler engineers trying to be cute more than improving things. The added complication and fail points over conventional leaf springs, which designed properly can give you minimal wrap and a comfortable ride, seems like it was designed to be more show and less go. There are lots of ways to remove axle wrap. And if they were going to put a mounting point on top of the axle then placing a designed traction bar to that point would completely eliminate axle hop.
Sometimes the bandaid looks pretty. But it's still a bandaid

[Will]

Maybe that center shock is just to keep the carrier housing from spinning on the axles haha

[adeluca73]

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....

[stubiePW]

Wow. Good write up. I also now feel a whole lot dumber haha

[Will]

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....

Well if that's the case, if you change the shocks or take off the rear sway bar, you can throw all that shit out the window because you just changed the systems resonance point and moved it outside of the predetermined vibration profile.

[nts007]

So u vibrate like a 12v diesel. I like this adeluca fellow. We will keep him round a bit longer

In my mind though they should have done a modified version of this. Maybe a 4 link but it removes the trac bar and rides very well yet is flexy