Mopar_Mudder

Looking for anyone personal experience with long gooseneck trailers and how they ride. I have a 40' tandem dually and it seems to do quiet a bit of bucking going down the road, and have alot of frame twist to it.

First I bought this trailer used and I know from looking at many new trialers it is not the heaviest best built one out their. But for the price I couldn't pass it up.

The main beams are 10" x 22 pound I-Beams, they seam a little close together to me. They could have been spaced another 8" apart and not gotten close to the tires. Also their is no "X" bracing of any sort between the I-Beams.

I have been thinking of many things. From trussing the bottom of the exsting I-Beam to replacing the existing I-Beam with a 12 or 14 inch. And widening the axles to get the beams further apart and a wider stance.

Just thinking out loud and looking for any opinions.

rich

My 33ft bucks when its empty and a little loaded but what do you expect for 10k axles and springs. the frame does flex and twist but i think that is to keep it from breaking or bending under the stress. I have sen a few with a pipe runnung down the middle to prevent twisting. The more weight you put on the trailer frame is less that you can haul. i have probably tweaked my trailers frame a little but i put it under severe conditions. Like unloading and loading dozers at weird angles due to pavement conditions. If you have a problem it might help to take it to the dealer or manufacturer

pocketchange

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My littlle G/Neck is a 40 footer w/6' spread, also purchased used. I replaced the spring eye bushings and bolts, moved the ball from over the axle and in a well (11' stakebed body), to forward 6" or so and up to allow for the AirRide 25K Hitch.
If I told you the trailer disappeared, would you believe me? Also replaced the OE shocks with BILSTEINS, now if I can only figure out how to install my overpriced airride seat from the big truck I sold to go into the Hot Shot business, I'd be good to go. Almost forgot, (sorry) a 110 gal aux. tank behind the cab didn't hurt, put some weight on the front axle, which also reduced the bouncing.

Scotty

I beams will twist and then give a bounce when they go back to the normal position. I had one I Beam gooseneck, it was stolen. I replaced it with a tube framed gooseneck and then IU switched it to a 5th wheel coupler just slightly forward of the turcks rear axle. No bounce. I had a 53ft wedge made from pre stressed tube steel ladder type side frames...one solid trailer. IT would bounce a bit empty...I attributed that to the 14 ply tires and 8,000 pound axles.

Now I am looking for a 25-30ft flat deck for 5th wheel or gooseneck...used, to modify a bit for hauling strongman equipment.

Mopar_Mudder

Just to update you I have cured much of the problem.

First off I welded another 6" I-Beam to the bottom of the existing 10" I-Beam which really cured most of the problem.

I also added some more set screw that hold the height adjustment on for the gooseneck in place. Their was some flex happening their with just one set screw. Haven't pulled it with a load on it yet but will this weekend. Loaded was never much of a probem any way, it was empty that was worse. I would say it is 90% better now then it was.

Haulin_in_Dixie

I can only speak from my experience with the trailers on the Dodge. The shocks fixed most of my bounce loaded or empty. I never could keep the set screws from slipping with a load so after twisting off two of them in the hitch head, I went up where it would not cause any weakness and drilled all the way through and installed a head bolt all the way through. You will find that empty it will ride better with the coupler higher which puts more weight on the rear axle, therefore loading the truck more and does not seem to make a difference loaded.

About the seats, I have two brand new air seats here, one never even installed in a truck, top of the line fore/aft slide, etc. I measured any way that I could to install them. My stock seat is 15 inches from the floor and the lowest position of the air seat is 16 inches. I am a big guy so no go. I plan on getting a low profile air seat soon and recover to match the passenger seat. I have had two back operations in the past and really need it.

I don't know how good you were at geometery in school but if you play with the angles involved with hitting a bump going down the road with the trailer you will learn a lot of what happens. Shocks will help much and you might try good shocks on the trailer also. When the trailer wheels hit the bump, the truck rear axle has just been driven up and when the trailer hits it drives the rear axle of the truck forward and down. Anything that you can do to dampen this effect will help greatly.

If you can follow this, the front truck axle hits the bump, drives the front of the cab up, next the rear axle hits, drives the rear of the truck up and the front back down, just about when it gets to the high point the trailer axles hit and drive the rear of the truck back down and foreward giving you the back slap thing.

Have someone else drive and you look at the pickup bed going down the road and also in the mirror. If the pickup bed is bouncing visually, you need better shocks on the truck. With good shocks the pickup bed will stay solid visually. See it is not the pickup bed that is moving it is the cab mounts on rubber. Good shocks will not ride smoother, but will stop the up and down beating of the cab.

Hope all this helps some, might give you some different ideas to think about.

Mopar_Mudder

My hitch is a square tube and already had a pin in it, just like a jack extention has on it. So I didn't have the problem atleast.

You could see the trailer bed flex up and down when empty that is why I added the extra beams and it is pretty solid now. I think the trailer axles are also mounted further ahead then most trailer so the boncing from the tail of the trailer comes up to the truck easier.

I may try better shocks like you said, I will see how it goes with a load on it this weekend first.

P Kennedy

General rule of thumb, soft springs in truck make it ride nice empty-but trailer will always transfer vibration ahead to tow unit. Put airride on trailer and problem with truck vibrating and bouncing will 90% go away but air ride on truck will not take out hitch impacts from trailer. Secondly flexing in the trailer frame is good as rigidity will transfer more road vibration forward from trailer axles, however loading of items on trailer directly over axles (truck or trailer) will always ride better than concentrated over center of trailer between axles. Making the frame too rigid will cause cracking elsewhere. A long trailer should be arched for better strength without adding extra beams and weight. Look at a semi flatdeck/stepdeck unloaded and a good one will be arched, if it is saddlebacked and then loaded it is tired and will ride like crap. Semi's are rated at #lbs per #ft ie: 50k/10ft (good) vs 25k/25ft (poor)- gooseneck flatdecks generally are not pre-stressed with an arch (cost factor) but will benefit far more than adding un-necessary pig iron. Anything under 20ft kingpin to axle centers usually wont make much difference but if the frame needs to flex an arch makes a big difference in frame, trailers with beaver tails have the reverse problem of being work arched from loading heavy without blocking the end of the trailer. Some flip down ramps have this built in feature, trailers that don't are also prone to bent rear axles from loading or broken springs and mounts. And to think it is just a hunk of welded metal with wheels. PK