Need help with a strange trailer problem

[montanaman]

I guess I should have mentioned that the HD2500 that I towed this with was an extended cab long bed and the dually is a crew cab long bed so I should have more than enough wheel base.

Ken

 

[RobS]

My fifth wheel RV does the same thing and my bumper pull flatbed does some bucking but it's entirely different than the fifth wheel. Likely has to do with where the hitch point is on the vehicle. On the fifth wheel versus your gooseneck, the hitch is higher which seems to me would make it worse. Ideally, the hitch would be right at the axle centerline in which case you would have no torque loads, only straight loads.

Have you had others drive it and can you pull a different trailer to compare? Might just be the nature of the beast.

 

[jarokoro]

I would tend to believe it is from trailer flexing or as George2615 already mentioned harmonic movement. I have a custom fabricated 20 ft GN channel iron trailer. When I picked it up from the trailer manufacture, I could not drive it faster than 40 miles an hour without bucking. I had to drive about 20 miles and at first thought well maybe its because its empty?, light weight?, GN height
? and then noticed the trailer would start flexing and twisting and it would be extremely exaggerated by any bumps or road transitions making as you say your chest hurt.

When I got home I called the manufacture and they tried to tell me there was nothing wrong. Therefore, I checked the GN it was off so I adjusted it and there was no change, so I loaded my Tractor some improvement but not much. So I took the trailer back and took the trailer manufacture for a ride. Within two minutes and three pavement transitions he said he had enough.

We went back to the shop and they did some bridging, stiffened the trailer, and put a rail on it. No problems since. Pulled it all over this past year and twice to Michigan. This last time I went to Michigan I pulled it empty and picked up a backhoe attachment. The time before my wife went with and I was pulling my tractor and bushhog, scraper and rake. My wife thought the ride was better than her 2003 Suburban. I was pulling the set up with my 2006 3500 4x4 see pic.

 

[Ford960]

I agree with jarokoro on this, trailer frame flexing is causing the trailer to set up a bucking motion in the truck. It really comes down to the manufacterer building a stiffer frame and adding things like a torque tube to prevent the twisting and flexing.
Also, Bird mentioned a Mor-ride system for fifth wheels and I don't know if it's Mor-ride but I have seen a gooseneck cushioned hitch tube adapter. I checked all my normal saved trailer websites but couldn't find one but I know that it exists.

BTW, Nice rig jarokoro.

 

[jarokoro]

Heres a link to a cushioning coupler, but I think unless the trailer gets a little stiffer you will still have problems.
PopUp Industries: Gooseneck Gooseneck Cushion Couplers

 

[montanaman]

Thanks for the input. Just seems like my life story to pay for things after really thinking hard about who to give my money to and I still end up let down. The truck is sitting outside now with the tailgate down because I had a bed liner sprayed in it yesterday and the tailgate latch no longer works. It's 10deg outside and I really don't care to spend MY time out in the cold fixing what worked perfect before someone else touched it!

I'm still thinking about the flexing. The trailer I have is channel but it is a deck over style and the main frame and gooseneck channel is at least 8", could be 10" channel. The uprights from the front of the frame to the gooseneck have a very large heavy triangular plate welded in like most do. If it is flexing, it would all have to be where the front of the main frame is welded to the gooseneck uprights because on the deck side of these uprights, there is no triangulation.

Wish I had time to take the truck to the bed liner guy and the trailer to the trailer guy and actually have them both fix the problems but I've been on earth long enough to know better.

What puzzles me is that I have not talked to anyone with this same trailer that has had towing issues. There are a lot of this brand in my area and any time I see one, I ask the owner. I have a tractor customer that has two of them and loves them.

Guess I'm just lucky!

Ken

 

[jarokoro]

Montanaman,

The flexing I got was not from the Gooseneck portion but from the trailer deck. It was flexing up and down also at the same time twisting the entire length. When I would hit a transition it would shock the trailer and truck suspension and transfer that to the truck hitch and feel like the hitch was going to break or I was damaging the trailer.

Not being an engineer by trade, my thoughts on the shock load is the GN hitch ball being abruptly stopped or forced in another direction opposite the motion twisting of the trailer. That load needs to be transferred somewhere and the only place is the hitch/coupler. At that time, I had a 2004 2500HD extended cab also.

As far as the trailer goes, I know many manufactures offer an upgrade of a torque tube set up that counteracts the twisting motion on trailers that are long. I also think that if you pulled another trailer with your setup it would more than likely handle the same.

 

[wushaw]

Your having frame twisting/tourquing problems translating up to the truck.
I have a GN dump trailer that does the same thing but it ain't that bad with the truck I use to tow it with but it can be rather harsh with a one ton.

I know it's the frame since when empty it does not do it till I load it...your trailer may be heavy enough to do it empty.

 

[montanaman]

I was picking up a fifth wheel hitch from a dealer that I buy from this AM and asked him if he thought there was a chance it could be the equalizers or spring bolts and we both sort of thought that by now, something would have loosened up or broken!!

No, I haven't had a chance to look at them yet. Too busy with projects that pay to get to my own.

I was also thinking that if there are SO many people with this trailer NOT having any problems towing them, maybe I shouldn't worry so much about trying to sell it?

I have a friend who would likely buy it right now and I could always insist that he give it a test pull first.

Looked at a Top Brand today and I really liked the looks of it. Heavy I-beam frame, high gooseneck,5' beaver tail,and even Good Year tires! I can get a really good price on it too.

Ken

 

[sandman2234]

Before you sell it, load a single tractor on it, a little further forward of where you would normally tie it down and go for a ride. Then move the tractor one inch backwards, go again, and keep doing this until you find the sweetest ride you can get out of it. There is a point at which the tongue will get light, so be careful with that.
I am reasonably sure you will find one point that rides a lot better than most of the rest. Since they build trailers pretty much the same way for the same model, and nobody else is having trouble with them, maybe they got lucky with the loading.
What can it hurt to waste a few gallons of fuel and half a day?
What you are discribing is hard to get out of a trailer that is loaded with the belly full (center loaded). Even tractor trailers have some problem with it.
David from jax