Hello forum, I obtained some cheap I beams, they are 8.25" tall, 5.25" wide and I have about 13 pieces in various lengths. The wall is 1/4inch thick and the top and bottom rails are 5/16" thick. I calculated it to be about 18lbs/ft. Would this be strong enough to build a 25ft top deck and a 3-5' dovetail gooseneck? I plan on using 3 6,000lb axles but probably wont ever load it that much. Heaviest load I have for it is a Tractor or Forklift, both 12,000lbs. If its not strong enough I have some 3/16" diamond plate laying around that could be used to box one side of the the I beam if the Beam alone isnt strong enough. I plan on using either 3" or 4" channel as cross members to hold the wood deck, and not decided on the side rails, maybe 5-6" angle or something else. So would that 8'' beam be strong enough? Or DO I need something taller?

 

Usually, what happens when I build a gooseneck, is that I build it way too stout and heavy, kinda like a boxcar.

Going by your measurements, it sounds like the frame should be plenty strong for sensible loads.

Do you have a way to turn the frame upside down??

It makes it a world easier to mount spring-hangers, etc., and get a good weld.

Big, stout gussetts at the neck and a wrap-around 1/4 X 4 piece of flat stock reinforcing the hitch to neck will make for a strong set-up.

 

That sounds alot like what we built right here.

31ft. long, 3 6,000 lb axles, we started with a comercial trailer and built the deck onto it. 1/2" thick rub rail, pockets take a dimensional 2x4, Outer channel is 6" high, crossmembers are 4" with 2 by treated southern yellow pine deck. Trailer weighs 6,000 lbs. ready to roll.

None of our trailers have a 8" beam in them most of them are 6". Just make sure when you do the neck that like BearKiller said, box the joints and make sure you build it high enough clear the bed(flat beds don't have this issue) when your off road (yes I smashed the bed on my dads ford once) and long enough that you can turn with the tail gate down.

The rule of thumb is to use a 6" outer beam with 4" crossmembers so you have 2" for your deck. Or 5" outer with 3" crossmembers. Like we did with this trailer.
20ft. with 16ft straight 4ft of dove tail, 2 7000lb axles with 8 lug 235-85-16 on it. The frame is a comercial box tubing setup, used to be a recycling trailer with multiple bins that dumped hydralically. Hydraulic landing gear is still on it. The deck was built low with 1/4" diamond plate fenders. This trailer is 5000lbs empty, heavier than I wanted for a 20ft trailer, but it works.

 

I agree with these guys, but check with Kauffman Trailers in Denton NC-----go to there website Kauffmantrailers.com-----you should see that they are out of NC. They have on there website there frame sizes + axle weights------but as far as the last post, make sure that you factor in your clearance for the bed with the tailgate down. Triangle bracing from the Horizontial portion of the goose neck down to the vertical portion of the goose neck will add for extra support. I have 1/4 in thick sheet's cut in for the extra support on the goose. Good Luck and take some pics when you get done!!!!

 

Also, a break-over neck is much stronger than a straight neck; it also allows for more clearance.

I think that I allow eight foot from ball-center to foremost part of trailer head-board for plenty of swing room; but, I can't remember for sure and it is dark and muddy out there where the trailers are.

 

Those are some pretty handy looking trailers.

Oh yeah, who is the three-legged man in the picture??

Was he born like that??

 

Thanks guys, JD730 the only difference in my build would be mobile home axles, they look ugly but get the job done. I have a 6klb/capacity forklift and a family of jack stands I dont see a problem in flipping it over to get the bottom parts. I think I'll make the bottom frame first fully prepared w/o deck and then build the neck seperate and join the two. I see it difficult to get the whole thing to flip with a forklift after the neck is installed, so finishing the bottom first then adding the neck later seems about right. I have plenty of 3/16" diamond plate I'll use to triangulate the frame and neck to get a strong joint.

Question: How does that gooseneck ride behind your truck, being that its only ~30ft with 3 axles? Another problem is I dont know if mobile home axles are allowed on new trailers or built trailers in California.

 

Mobile home axles are usually 6-thousand pound Dexters with "mobile home" hubs.

Regular hubs can, in most cases, be swapped on to them.

It is not the axles that are a limiting factor; it is the tires that are designated "mobile-home use only."

Regular trailer-use 14.5 tires are available that are D.O.T. approved; load range G are around $90.

 

That 30ft is the deck and the tail, so the whole trailer is longer than 30ft. That one is setup with a inverted mini-5th wheel. The last truck to pull it was our 86 F250, because my 2000 CTD is too high for it. But it pulls great the only problem is when you pull into different place with the deck so close to the bed it might touch and in my case crush the bed. (good thing it was the old truck) Really a pain when you can't pull into certain gas stations.

Bearkiller nailed it, thats pretty much what those axles are only with 6 lug hubs instead of the spoke with wedges (nothing wrong with them BTW lots of other trailers here have them on with good load range G tires instead of the mobile home only). Talk around here has been maybe we'll put on a set of 8 lug hubs we have and run 16" truck tires. As soon as it warms up we're going to work on our '82 Internatioal crew cab w/ DT466 and set it up with a flat bed to pull this trailer and any other out there.

 

I had GPI Line in Missisippi build mine ( bought it through Country Classic Trailer Sales on Old Randallman Road in NC) and they used 10 inch eye beams because I wanted a 24 foot flat with a four foot dove tail.

 

I think my 24+5 Titan with 10k tandem duallys has 10 in. I-beams?? Maybe it is overkill though?? IDK

 

I could be wrong but I think since you are building the trailer yourself the only regs you need to follow are the tire and lighting regs also length and width, I would need to read up on it at work I manage a trailer mfg co so we have the info there

 

a fabricator friend of mine is right now building a 20-25ft detachable gooseneck trailer outside frame. He is very innovative and endlessly knowledgeable. It will have tandem dual axles on torflex suspension. I will get pictures as he builds it.

 

With a load like this, I want to make sure it don't break and leave me sitting or worse, come apart and hurt someone. This was 12,000 pounds even plus the trailer. And yes, that is eight chains on two tractors.

https://www.dieseltruckresource.com/...cat=500&page=2

 

I also have 56ft of 12"/24 or 25lbs I beam which I could use, but I wouldnt have enough for the neck, would probably have to use the 8" beam for the neck part but I dont like that idea. I think the neck should be as big as the frame, so I;ll stick with 8" I beam.

Another thing I was pondering, my fathers trailers are 48' and 53's and they have tandem sliders, pretty neat deal that allows the driver to put more weight on the trailer axles or distribute it over to the truck. Now I know this would be overkill on a little gooseneck trailer but it could be handy. I have a couple of ways of making this setup, the one I like is using 2x2 or 2x3 tubes on the bottom of the rails that would attach to the axle pedestals. And using 3/8'' thick plate on each side of the bottom rail with a 1/4" in the middle and the 2 tubes (on each side) between the 3 pieces of flat steel would kinda make a hair comb. The tubes would then be able to slide forward and back between the 3 pieces of flat steel with holes drilled every ft or so. Then I would use a 1" round bar with spring pressure to lock in the flat stock and the tubes during travel. Similar to a big rig setup. I can make this work but the only doubt in my mind is when the trailer is going to turn, and tires are going to scrub, I dont want that rail to break out from underneath the I beams.

Tow trucks would be the dually or the f250 shop truck, so I dont want to overload the rear axle on that truck so moving the axles seems like a neat trick. But then again, it;ll just complicate the process and more parts = bigger possibily of having a part failure.

Now the length, 25' + 5' dovetail with a 12" drop at the end, would I be able to get 2 cars on there if I wanted to? Or do you guys think the bottom would be too close to hit the rear edge of the topdeck?