Uncontrolled Bouncing

[Nature Ist]

I agree with the opinions offered already, especially that shocks are a first suspect.
My next thought is highly unlikely, but did you consider the possibility of trailer load balancing issues? For fifth wheels, this would be more likely a problem with a toy hauler or pulling another trailer in tandem, but load imbalance (too much rearward) can result in some odd experiences. I wouldn't think you had much significant weight in the back of that unit unless you piled it on the couch! As we all know, this is big concern on travel trailers, but it is something fivers need to remember.

[rkymntsno]

Originally Posted by madmaxmutt

It sounds like you are sure it was the rear of the truck. I would want to make sure it wasn't death wobble in the front suspension. I have heard that can feel like the whole truck shaking violently.

Short of that, I would be checking the rear of the truck and the trailer suspension for anything that looks amiss or loose. There have been several threads on here about broken suspension parts (hangers, springs, etc...), and one about a hub that sheared off the trailer.

Yes, it was the back of the truck. It was just a dip in the road and the bouncing just kept going. A helluva dip I should say. Worst one we've hit.

[rkymntsno]

Originally Posted by Nature Ist

I agree with the opinions offered already, especially that shocks are a first suspect.
My next thought is highly unlikely, but did you consider the possibility of trailer load balancing issues? For fifth wheels, this would be more likely a problem with a toy hauler or pulling another trailer in tandem, but load imbalance (too much rearward) can result in some odd experiences. I wouldn't think you had much significant weight in the back of that unit unless you piled it on the couch! As we all know, this is big concern on travel trailers, but it is something fivers need to remember.

Thanks for the insight but no, wasn't overloaded anywhere and we were actually pretty light except the front basement behind the tailgate of the truck. I think it was the speed we were at, 68 mph, and how bad of a dip it was.

[Nature Ist]

Originally Posted by rkymntsno

Thanks for the insight but no, wasn't overloaded anywhere and we were actually pretty light except the front basement behind the tailgate of the truck. I think it was the speed we were at, 68 mph, and how bad of a dip it was.

I would have been quite surprised if that was a factor. Another thought: with the long bed and no cab clearance concerns, do you have your hitch pin centered forward of the rear axle? Depending on what hitch you have and where it is set, that can help with pin weight on rear axle. I got good results on my B&W hitch when I moved it to the forward-most position, it put more weight on the front and reduced the rear end sag.
Again, I don't think this is going to solve your bouncing, but it may be worth considering.

[rkymntsno]

Originally Posted by Nature Ist

I would have been quite surprised if that was a factor. Another thought: with the long bed and no cab clearance concerns, do you have your hitch pin centered forward of the rear axle? Depending on what hitch you have and where it is set, that can help with pin weight on rear axle. I got good results on my B&W hitch when I moved it to the forward-most position, it put more weight on the front and reduced the rear end sag.
Again, I don't think this is going to solve your bouncing, but it may be worth considering.

We've had this setup for three and a half years and this is the first time it was this bad. I still think it was an extreme dip.

[Bigdog]

Look for my thread “Nose High and Bouncy”. Lowering the hitch head one inch and moving it forward two inches made all the difference in the world for me. No timbrens, air bags, new shocks, etc, required.

I found this week that setting the cruise on 65 instead of 67 makes the ride even better. I believe I’ve found the sweet spot.

[MtnGoat]

Took the DW Honda on an adventure today. We spent some time watching TTs and 5rs bounce down the highway. Which got me to thinking about tire wear, springs and wheel bearing failures. What makes these suspensions different from Cars and trucks.....Shock Absorbers

[Noblewk]

I tend to agree with some of the others in that the SHOCKS are what would control the "Bounce", "Bounce", "Bounce". Timberlins, Air Bags, and Sumo Springs should only help you "level" your load, some better than others. We have Air Bags so we can adjust the Ride Height and comfort while hitched or unhitched. Our Pin Weigh is 4200 to 4900 depending on how much water we are carrying, being able to compensate for that weigh in ride height makes a huge difference.

[joe w]

Considering that calling the spring dampers shocks is a misnomer I would seriously consider quality set like Bilstein's.

[rkymntsno]

Originally Posted by joe w

Considering that calling the spring dampers shocks is a misnomer I would seriously consider quality set like Bilstein's.

I was thinking Bilstein's also. If I were to go with the shocks, would I replace all four or could I get away with just the rear shocks?

[kblast523]

Originally Posted by TxLoser

...usually it’s one oscillation and done. Yes, roads are terrible these days.

Could it be coming up off the Timbrens and then bouncing on them. I’d pull the Timbrens and find some rough highway for a test tow to see how it does. Depending on miles on the truck, it could also be time for new shocks if you’ve not already done this.

I put Sumos on my 2015 F-150 pulling a 7k trailer in an attempt to fix sway. Fixed everything BUT sway...nothing fixed it so I traded tt's.
After trading tt's, a year later traded trucks to a 2019 New RAM 1500. Put Timbrens on it and it became a rolling bouncy house on certain roads. FCA (now Stellantis) took care of that by reacquiring the vehicle (for other reasons) under the Texas Lemon law. My marginal experience with Timbrens led me to put Sumos on my current tv, a 2018 Nissan Titan. The only ill effect is the FRONT of the truck can get bouncy on certain roads but I am almost certain the struts are getting weak, and replacements on hand.

[jimmoore13]

Originally Posted by craigav

I would go ahead and change out the rear shocks anyway. Once you start bouncing as you encountered, it is the shock absorbers that dampens the bouncing.

While you certainly may have shocks that are just as good as new, however almost every factory oem shock is a balance between being too firm vs being too soft, which relates to the weight that they are damping (more weight more inertia). In any case they mfgs compromise here to meet the most owner's needs. Also, the stock shocks most commonly have a single level of dampening which mean the same dampening on a smooth road vs rough road, loaded vs unloaded results in the same dampening.

If you go with a shock like this (there are likely other manufactures... koni maybe), then these can make a big difference as what these do that almost all oem shocks don't do, is these become much more firm (more dampening) when hitting a big bumps or other similar situations that would cause uncontrolled bouncing. Once those conditions no longer are occurring the shocks become less firm allowing for a smoother ride on a smoother road.

I will say though that the cause of the bouncing may still exist after installing new shocks so pin weights, tire pressures, and all other factors should be considered, but if such a bounce does occur again, having shocks that have more dampening capability will certainly be of value to stop the bouncing more quickly, especially considering that you would also have a smoother ride otherwise.

Also, disclaimer, I have used Bilsteins on my Ford E450 motorhome and my Chev 2500HD (which I pulled a ~30' 5th wheel with) and can report noticeable improvements on each and a much better ride overall, but I don't have any personal experience with a Ram pickup truck.

Bilstein 24-238533

https://cart.bilsteinus.com/details?...71853036048834

btw, just rambling, have you ever seen a road, highway, or interstate and right after a bridge sometimes you see a lot of oil stains on the road and then you hit a dip and up ahead maybe 30' another set of stains and you hit the next dip, followed by maybe another and another. All that oil indicates that many vehicles are hitting these dips and whatever they may have to drip off of the engine\transmission does so. In any case, with a 5th wheel sometimes the spacing of dips in a road could be at a frequency that makes it worse than would be otherwise. Better shocks could help a lot, but can only do so much, slower speed helps as well. ~CA

X-2.

RAM tends to tune its suspensions for a cushy ride...especially on the 1500 series. With any load, they can be wallowing pigs. I have a 1500.

Springs provide lift and prevent sag. Shocks dampen oscillations. I have airbags on my truck to prevent the stock rear suspension from sagging under load. Once the truck is loaded, I add air to the bags until the the truck is level again.
I replaced the "lost at sea in a violent storm" OEM shocks with some decent Bilsteins. This did a lot to get rid of wallow and uncontrolled oscillation brought on by the pogo effect of all that weight on the fifth wheel or bumper hitch pumping up and down.

The Timbrens do a lot to prevent over compression of the rear suspension, but they do nothing to stop upward movement once you go beyond their engagement point. The same is true of airbags. Springs will actually apply the weight of the rear axle assembly to somewhat slow down the upward jounce, but you have "factory" springs aided by the Timbrens, so there's no "extra" pull down as your pitching, pogoing truck/trailer sail upwards beyond the Timbren's point of engagement. Instead, the Timbrens push upward harder, and without decent shocks, there's nothing to prevent that porpoising.

I couldn't tell from your OP whether you applied just the trailer brakes or stabbed at the truck's brake pedal. In a control situation like this, you almost always want to ONLY apply the trailer brakes to regain control. The trailer drags on the truck to keep it going straight while burning off some speed. That action may have little impact on the undampened porpoising, but it will keep you from making a bad situation worse.

On shocks...you don't need anything like this, but FYI, many off-road trucks will have TWO shocks per corner, and those will often have remote reservoir shocks to aid with cooling and prevention of foaming of the damper oil. This is how important shocks can be.

As you learned the hard way, flacid shocks can be dangerous.

[Mad5581]

To answer your original question yes airbags would be a great solution. I have them on my gmc 3500 srw and they are a game changer. I pulled my 377rlbh once before installing the airbags and it was a bit unstable at 65mph. With airbags it totally changed the entire dynamic of how the trailer road and pulled. I personally have the onboard compressor so it's nice when the roads get a bit rough to put 5 or 10lbs extra air in. Makes the ride a bit rougher but definitely isolates all the extra bounce. I run about 45lbs in them when towing normally and in Wyoming on a really nasty road I had 65lbs In them and I was comfortable at 65 to 70 no problem. Would a drw be better probably. Is an f450 upgrade worth it? I don't think it's necessary. I think if your under 3500 lb pin and under 17k trailer weight an f450 is overkill. But that's my opinion. The f450 is a great truck but I personally don't care for DRWs. If all you do is pull then they are great. But I use my truck as a daily driver too. I like personally like the Firestone airbags kit better then the air lift kit. My last truck had the Firestone kit my current truck has the air lift kit. They both work fine but the Firestone kit just seemed to dampen the bounce better with less air in them. They also seemed to ride better when unloaded. Just my personal opinion

[JFlightRisk]

Originally Posted by rkymntsno

I was thinking Bilstein's also. If I were to go with the shocks, would I replace all four or could I get away with just the rear shocks?

One of the first things done to our truck was replacing all four shocks with Bilsteins. I got used to them on our Tundra TRDs, and was spoiled. The OE shocks didn't make towing as pleasant.

[jayco13]

I have a 2015 Ram 2500 Cummins SRW with the factory air ride. I also have a 2016 355MBQS. I have towed this about 30k miles mostly for 2-3 trips annually from Pennsylvania to Walt Disney World in Orlando. I have never experienced what you are talking about. I wasn’t sure about the factory air ride system when I purchased the truck but I have been very pleased with how this set up has performed for me over the years.

[Mad5581]

I'm sorry I always have to cringe when I see a comment about grabbing the trailer brake controller when something violent is happening. If you read the instructions on most all trailer brake controllers they say never use the applicator for anything other then testing the brakes and insuring proper adjustment. Now I've got over a million on my way to 2 million safe miles and I have never used the trailer brake controller to regain control. NEVER.. almost any loss of control because of up and down movement can be regained by simply letting off the gas. If you hit the foot brake it will amplify what is happening. If you give it more gas (I know unnatural response) you can almost always overcome the movement faster. You grab your trailer brake controller you will almost 100% of the time because of adrenaline grab too hard. And likely create a situation that is worse then what your attempting to get out of. Now not to say there are not thousands of lucky people that have achieved favorable outcomes by grabbing the trailer brakes but it not actually the right way to overcome a loss of control situation. The best thing you can do is let off the gas and let your rig naturally slow down. If your on a steep grade going down light controlled foot brake applications. You need all your brakes to work together not just the trailer brakes. I have personal trained many truck drivers and knock on wood have never had one in a major wreck. The number 1 key is to not let yourself get into the situation to start with. If your truck responded to a big dip in the road with violent behavior like you mentioned. 1 your rv is too much for your truck. 2 your trucks suspension components are worn out and need replaced. If your within your capacities then I would say your components are worn-out. If your over loaded then well only 2 options smaller rv or bigger truck.

[craigav]

Originally Posted by Mad5581

I'm sorry I always have to cringe when I see a comment about grabbing the trailer brake controller when something violent is happening. If you read the instructions on most all trailer brake controllers they say never use the applicator for anything other then testing the brakes and insuring proper adjustment. Now I've got over a million on my way to 2 million safe miles and I have never used the trailer brake controller to regain control. NEVER.. almost any loss of control because of up and down movement can be regained by simply letting off the gas. If you hit the foot brake it will amplify what is happening. If you give it more gas (I know unnatural response) you can almost always overcome the movement faster. You grab your trailer brake controller you will almost 100% of the time because of adrenaline grab too hard. And likely create a situation that is worse then what your attempting to get out of. Now not to say there are not thousands of lucky people that have achieved favorable outcomes by grabbing the trailer brakes but it not actually the right way to overcome a loss of control situation. The best thing you can do is let off the gas and let your rig naturally slow down. If your on a steep grade going down light controlled foot brake applications. You need all your brakes to work together not just the trailer brakes. I have personal trained many truck drivers and knock on wood have never had one in a major wreck. The number 1 key is to not let yourself get into the situation to start with. If your truck responded to a big dip in the road with violent behavior like you mentioned. 1 your rv is too much for your truck. 2 your trucks suspension components are worn out and need replaced. If your within your capacities then I would say your components are worn-out. If your over loaded then well only 2 options smaller rv or bigger truck.

Thanks for the many years of driving, I believe that Truck Drivers are certainly under appreciated.

I wanted to share that when it comes to smaller trailers (smaller than tractor trailers), all of the guidance I have seen states that if "Excessive Sway" occurs, you should manually activate the trailer brakes and not apply the tow vehicles brakes. I have actually used this procedure when a huge wind gust blew the trailer 45 degrees out of alignment with the truck and was about to go over.

While I would have to search to find it, this guidance (using trailer brakes to control "excessive" sway) was published by the NHTSA many years back although I haven't checked lately to determine if their guidance has changed.

In the case of the OP with excessive bouncing, I don't suggest that hitting the trailer brakes would help with the bouncing, and not too mention 5th wheels generally don't have the same sway potential as a bumper pull. ~CA

[joe w]

Originally Posted by jimmoore13

X-2.

RAM tends to tune its suspensions for a cushy ride...especially on the 1500 series. With any load, they can be wallowing pigs. I have a 1500.

Springs provide lift and prevent sag. Shocks dampen oscillations. I have airbags on my truck to prevent the stock rear suspension from sagging under load. Once the truck is loaded, I add air to the bags until the the truck is level again.
I replaced the "lost at sea in a violent storm" OEM shocks with some decent Bilsteins. This did a lot to get rid of wallow and uncontrolled oscillation brought on by the pogo effect of all that weight on the fifth wheel or bumper hitch pumping up and down.

The Timbrens do a lot to prevent over compression of the rear suspension, but they do nothing to stop upward movement once you go beyond their engagement point. The same is true of airbags. Springs will actually apply the weight of the rear axle assembly to somewhat slow down the upward jounce, but you have "factory" springs aided by the Timbrens, so there's no "extra" pull down as your pitching, pogoing truck/trailer sail upwards beyond the Timbren's point of engagement. Instead, the Timbrens push upward harder, and without decent shocks, there's nothing to prevent that porpoising.

I couldn't tell from your OP whether you applied just the trailer brakes or stabbed at the truck's brake pedal. In a control situation like this, you almost always want to ONLY apply the trailer brakes to regain control. The trailer drags on the truck to keep it going straight while burning off some speed. That action may have little impact on the undampened porpoising, but it will keep you from making a bad situation worse.

On shocks...you don't need anything like this, but FYI, many off-road trucks will have TWO shocks per corner, and those will often have remote reservoir shocks to aid with cooling and prevention of foaming of the damper oil. This is how important shocks can be.

As you learned the hard way, flacid shocks can be dangerous.

Wallowing pigs? My RAM 1500 W/tow package has done a admirable job towing thus far over 14K miles!

[FashaPa]

Go to a heavier shock absorber. They are the only things to control bounce. Adding air bags can make it worse

[FashaPa]

Air bags do nothing to control bounce, if anything to add to bounce. Shocks control springs, both mechanical and air springs. A larger piston shock or a new pair of shocks should make a world of difference. No need to spend the money on Fox or the other 4-wheel drive shocks. A good Gabriel or Monroe truck shuck will do. Save yourself the money.