What Is Causing My New RV To Bounce?

Question

Question:

I need some expert advice about my trailer causing my new RV to bounce. Once I hear from someone, I can describe the problem in more detail! Thank you!

asked by: Lee W

0

Expert Reply:

Hey Lee. Yes I can help with that. What's going on? Send me as much detailed info as you have and I am happy to look into it and help you get to the bottom of it.

Typically, bounce is caused by worn out or undersized suspension components, or by the trailer being loaded way too light. Sometimes you can add a helper spring like part # TSS-106-40 to help stabilize things.

Lets see what you have going on and what can be done to address it.

expert reply by: Jesse M

0

Lee W.

2/25/2026

Hi Jesse, OK, here are the particulars: 1999 Wells Cargo Tote Wagon with torsional suspension (no leaf springs), loaded weight 4,000 lbs. 1999 Dodge Road Trek pulled it for 26 years with no problems, except for being pushed around by semi's. Installed Recurve R3 weight distribution hitch five years ago, which helped with sway. Just purchased a 2025 Thor Gemini RV built on the Ford Transit 350HD. It easily pulls the trailer, but in order for the trailer to be level, I had to buy a 9 inch drop shank to fit the Recurve, so now the bottom of the hitch is only 3-4 inches above the pavement (that's one problem). Thor and Ford say NOT to use a weight distributing hitch, but the Recurve also has sway control, so I have it installed but not really using the weight distributing aspect. Driving on smooth interstates everything is fine. But going through construction, or patched asphalt, or wavy interstates, or any kind of road that is not perfectly smooth, and this happens: when the trailer hits a bump, the tongue of the trailer bounces up and down, and flexes the entire hitch along with it. This is transmitted to the RV, which results is the RV shaking three or four times. Feels like someone grabbed the back of my chair and shook it. Very unsettling. The Gemini has a towing capacity of 5,000 lbs., and a tongue weight capacity of 500 lbs. With the Recurve hitich weighing about 75 lbs., I have the maximum tongue weight allowed. I never measured the tongue weight when the trailer was attached to the Road Trek, but I'm guessing it was over 1,000 lbs. Could that be why it didn't cause bouncing in the past? I can't put that much tongue weight on the Gemini, so what are my options? Buy a new trailer? Buy one of those expensive and heavy shock absorbing hitches? Install Sumo springs on the RV? Just live with it? I'm concerned about the hitch flexing so much. I'm afraid it will crack the hitch or even the Gemini frame. Any advice? Thanks!

Lee W.

2/25/2026

Also, the hitch is a Lippert Class IV. Max towing capacity 5,000 lbs, Max tongue weight 500 lbs. It is bolted onto the frame extensions that are bolted to the Transit frame rails at the factory, since this is the extended wheel base Transit.

Jesse M.

2/26/2026

@LeeW Hey Lee, thanks for laying all that out. In my opinion, there are a few things that are likely causing or contributing to the bounce problem you are describing: - Your Gemini RV has a lower tongue weight capacity compared to your truck and doesn't dampen the movement as much - The 9" drop shank is increasing leverage on the receiver which is amplifying movement - Torsion axles can weaken and wear out over time which can make bumps and rebound more harsh - You are maxing out, or possibly exceeding the tongue weight capacity of your RV That said, all the things you suggested are potential fixes - different trailer, cushioned ball mount, trailer helpers ect... Have you tried removing the sway control bars to see if that helps? Generally if a vehicles manual states not to use a WD hitch I would recommend leaving it off since it could be causing undue stress on the frame. A cushioned ball mount will help absorb some shock but you would have to do away with the WD hitch. If you have the means to get a new trailer with a taller coupler height, that will help but I know that might not be practical. That would get rid of the need for the drop shank, and newer suspension might just handle better overall. A trailer helper like the SumoSprings # TSS-107-40 will help to cushion some of that movement and stop as much of it from transferring to the trailer and vehicle. This is more of a quick fix or band-aid though. If your torsion axles are worn, there aren't any replaceable suspension parts so that would mean new axles. Leaf spring suspension might handle better too. Torsion axles can sometimes be more bouncy and springy which might be contributing to what you are seeing.

Lee W.

2/27/2026

@JesseM Hi Jesse, thanks for the response. Your point about having the 9 inch drop shank resulting in increased leverage on the hitch makes sense. The reason I did that was because I thought I needed to get the trailer as level as possible. If I raise up the hitch ball, that would chip the front of the trailer up, increasing tongue weight, since I would be taking some of the weight off the front wheels of the trailer. I see a lot of people driving around town with their utility trailers tipped up like that. I suppose I could do that, and compensate for the increased tongue weight by putting more weight behind the tandem axles, I’m just not sure that would help any? I crawled under the RV and looked to see how things were constructed. The white painted. vehicle frame ends just past The rear leaf spring shackles. Then there is a white painted frame insert that extends about 2 feet into the frame, and 8 inches towards the rear of the vehicle. Then a Z shaped black painted frame piece is bolted onto this extension. I don’t know. if this was done by Ford or by four. Since it is a different color, I am leaning towards it being added by Thor, but I don’t know. These black frame pieces extend 4 feet to the rear, and that is what the hitch is bolted to. But they are basically free-floating. my thoughts are that because these framed pieces are so long they are flexing up and down and causing the RV to bump up and down. Does that make sense? Maybe that explains why I can see the hitch going up and down so much in my rear view camera. Maybe that also explains why the RV has a maximum tongue weight capacity of only 500 pounds? I don’t think Ford transit usually have much more than that, though, even if they aren’t RV’s. It looks like those sumo springs are designed for trailers that have leaf springs, which is not my case. I did, however, noticed that the leaf springs on the RV are basically flat. I have heard of other people who installed sumo springs on these RVs to improve the ride, and I wonder if they would help with the bounce? You are correct, I am near the maximum tongue weight rating but I haven’t gone over it. I don’t really understand why weight distributing hitches are not recommended? It seems like if there is excess tongue weight, reducing that tongue weight and transferring it to the trailer, wouldn’t hurt the tow vehicle. By the way, I did try removing the bars from the weight distributing hitch and didn’t notice any difference. I really like this way control so I’d like to continue using them, even if they are carrying any weight. How do I know if the torsion axles are worn out? The trailer does have about 150,000 miles on it. I would be OK with replacing the trailer since this one is 27 years old. I just need to find one that would be light enough and yet big enough for all of my teaching supplies. Any recommendations? I’ll send some pictures of the frame extensions so you can see what I’m talking about. Thanks for your advice!

Jesse M.

2/27/2026

@LeeW Hey Lee. Yes I believe the hitch is something Thor adds. The part you said about the frame pieces flexing makes perfect sense and I bet it is definitely contributing to the "shaking" you are feeling. I'm thinking its that, plus a combination of the drop shank and high tongue weight. The axles being worn is possible but its so hard to say for sure since there are so many factors that contribute to wear and tear on an axle. They can easily last way more than 150,000 miles if they are taken care of and not overloaded or abused. Typically if a torsion axle is worn out you will see uneven tire wear, lower than usual ride height, excessive bouncing or lots of clunking or squeaking. As far as the WD hitch, the main reason Ford doesn't recommend using one on a Transit 350 is because of the unibody design. The WD hitch applies significant upward and twisting force to the receiver and frame rails. The Transit structure is not designed to handle those additional stress loads. I think this is also contributing to the frame flex you described. That could also mean the hitch itself is not designed to be used with a WD hitch. I do know that using a WD hitch on a unibody frame does run the risk of damaging the frame. Beefing up the rear suspension on your RV can definitely help lessen the shaking a bit. A Helper spring like the Hellwig # HE32VR is something to consider. Also, we do offer lift block kits for torsion axles. Adding one of those will help level things out a bit. I'd just need you to confirm the distance between the axle mounting bolts to make sure you get the right kit. If you end up looking into a new trailer, I'd look really anywhere that has aluminum frame cargo trailers. ATC, Look Element/Vision, Cargo Mate or Wellscargo are all brands that come to mind. Something with leaf spring suspension might provide a more stable ride too so that's something to look for. I'll admit I deal mostly with part and not so much on the trailer sales side of things lol Feel free to email me pictures. My email is [email protected]. I am here if you have any other questions or need anything else!

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