Trailer cross-braces

[dwall174]

I'm in the process of converting a 5th wheel camper into a flatbed utility trailer. The main frame is made from 5” X 1-3/4” X 3/16” thick C-channel & it has two 3500lb. axles with brakes.
There's currently only a couple of cross-braces & there just thin angle iron, So naturally I'll need to add some more cross-braces! My question is on what size & how many braces I'll need to use?

The main deck area is only going to be 6' X 12' & I'm planning to make the floor of the trailer out of 2” X 6” white oak, But I'm not to sure about how many & what size material I should make the cross-braces out of?

I was originally planning to use 11 gauge (.120 wall) 2” X 2” square tubing & space them at 24” But I haven't found any good info on the weight capacity of the tubing.

Is there any on-line calculators to help figure out the size of tubing needed for a given distance? I've seen some of the engineering formula's But that's all greek to me! I'm looking for something that I can put in the size of the tube & distance in-between the frame, And figure out what size & wall thickness I'll need!

Doug

 

[FTG-05]

I'd use what all the major trailer makers use and that's usually 3" channel, at least that's what is on my two car carriers. They are spaced 16" apart IRC.

Good luck!

 

[dwall174]

I'd use what all the major trailer makers use and that's usually 3" channel

I was thinking of using 3" X 1-3/8" by 3/16" wall C-channel, But I was wondering if the 2" X 2" X .120 (11ga.) might be just as good?

Price wise the square tube & channel are close to each other, tube is a little cheaper! But the 11ga. 2” X 2” square tube is also lighter than the C-channel, And I'm thinking it would be just as strong?

Doug

 

[Sureshot]

Without pics it is hard to say. I built a truck deck years ago with heavy crossmembers and it was so stiff I could not go up ditches at an angle as the truck frame would not flex. Te cross member should be on top or go with angle iron.

What is the goal of adding the crossmembers? To support the load or keep the frame square?

Why is the deck only 6' wide? Do you have a specific load it is being built for?

 

[dwall174]

What is the goal of adding the crossmembers?

Basically to support the new deck & the load on it! The camper had a wood 2"x2" & plywood floor, And the only cross-braces were used to hold the holding tanks in-place. There's currently no side to side supports or cross-braces other than the light weight angle iron holding tank supports.

Why is the deck only 6' wide?

After striping it to the frame I cut about 5' off the back of the frame making it just over 20' long total including the upper deck section so it would fit into my 2 car garage. With only a 12' main deck area, I really don't need to make it any wider than the width between the wheels which is 68”. The trailer is basically just going to be a heavy duty utility trailer for moving equipment for my wood & metalworking hobbies.

Without pics it is hard to say.

I don't have a working digital camera, But I'm going to try to get my brother to stop by this weekend & take some pic's for me. I do have a couple pic's of the trailer before I started the demolition.




Doug

 

[brewchief]

I would use channel, I've seen too many rusted out trailer frames made from tube, if any moisture gets inside the tube it will rot from the inside out.

 

[dwall174]

if any moisture gets inside the tube it will rot from the inside out.

Yea anytime I weld square or round tubing where it's going to be a "sealed joint" I usually try to provide a small vent hole to prevent any heated/trapped fumes from creating “Blow Out” just before the weld joint is finished, You can always fill-in the hole afterwords if needed. Even if the tubing isn't exposed to the elements it can still develop moisture inside the tubing due to condensation, So a vent/drain hole is usually helpful!

I'm leaning towards the channel or angle iron mainly because of more options on mounting the decking. With the square tubing I'm limited to using self-tapping screws, With the channel or angle iron I can also use good old nuts & bolts to fasten the decking down.

Doug

 

[koditten]

FWIW, consider mixing the cross members up. I like to use a combination of angle iron and square tube. The square tube will make the trailer stiffer. This comes from having 4 sides welded to the frame rails.

I've done what you are doing many times. These frames are quite flexable when you don't have the top of the trailer adding riggidity. You wouldn't think sheet aluminumn would make the trailer rigid, but it does.

As for the cross member, you will be fine using 14 gauge tube or 1/8" angle (I like 2 x 2)

Looking forward to progress pics.

Later

KO

 

[dwall174]

FWIW, consider mixing the cross members up

Good point! I'm probably going to want use thicker material over the axles, Since that's where I would try to place anything that's heavy.

I've done what you are doing many times

How far apart did you place the cross members?

As for the cross member, you will be fine using 14 gauge tube or 1/8" angle

Thanks I don't want to use too thin of stock! But then considering the extra weight & cost of meterial I also don't need to use too heavy of stock either!

Doug

 

[koditten]

If you use 1/8" tube and angle, you will have enough capacity to put a compact tractor on the trailer. You could carry a car as well, but the size of the trailer prevents cars from being hauled.

If you are using 2 x 6 lumber, the cross members can be aroung 20-23 inches apart. If you are using 5/4 lumber, space them at near 18". You just need to be close on those numbers I listed. When I build a trailer I dont even measure. I just eyeball the spacing to make them all look pretty close.

 

[dwall174]

If you use 1/8" tube and angle, you will have enough capacity to put a compact tractor on the trailer. You could carry a car as well, but the size of the trailer prevents cars from being hauled.

Yea the deck size would not let me haul a car, Well maybe a “Mini Cooper”
But I would still want it to handle a load of around 4500lbs. placed over the axles.

Doug

 

[dwall174]

Finally got some pic's of the frame after everything was removed & shortened down to the length I wanted. Haven't got around to adding the cross braces yet since I have some other projects that are more important before winter. But I found a good deal on some 11ga. 2-1/2" square tube so I'm probably going to use that.






Doug

 

[IHI]

Being how it's so tiny, what is the intended loads you plan to put on it? cars are out obviously so any serious weight is out of the question...don't over think it, I have a 8'x20' steel deck open car/utility trailer that uses 3x3x3/16" angle iron every 24" and then the diamond plate decking/fenders are welded to those and each other. It's hauled 753's, 280 bobcats and god knows how many cars and trucks over the past 16yrs without any problems.

 

[Ign]

Michigan......wow. The rust seen on those galvanized posts for the chain link fence is unheard of around here.

 

[IHI]

Michigan......wow. The rust seen on those galvanized posts for the chain link fence is unheard of around here.

Welcome to the upper Midwest, rust belt of the united states...freakin *****.

 

[CNGsaves]

Curious what led to plan to strip the 5th wheel camper and turn into a trailer?? That camper looked pretty decent before you tore into it. What was camper worth before tear down??

Also, why the idea to whack off 5 ft of trailer length on back?? With your layout now, you are forcing virtually all the load onto the "tongue" of 5th wheel. Due that weight on tongue, are you going to beef up front with some angle braces welded in??

Good luck with rest of build and listen to Koditten as he's the trailer pro.

 

[dwall174]

Being how it's so tiny, what is the intended loads you plan to put on it?

The length was cut down to allow the trailer to fit inside my garage & still be able to close the door. As for intended loads it will be used mainly for moving old woodworking & metalworking machines. Weight wise those old cast iron machines can get pretty heavy, It wouldn't take much room to get over 3000lbs. of equipment on the trailer. I hauled an old table saw in the back of my pick-up truck that weighed 1800lbs. & that only took up a 3' X 3' floor area.

Doug

 

[dwall174]

Curious what led to plan to strip the 5th wheel camper and turn into a trailer??

It had several roof leaks & there was quite a bit of interior structural damage. Also due to the leaks the rear floor was in bad shape! To fix it right I would have had to totally gut the back half of the trailer & replace all the rear side & roof supports.

Due that weight on tongue, are you going to beef up front with some angle braces welded in??

Yeah I'm going to add two "C" channel braces from the pin box to the corner side supports. I also need to add a heavier cross-brace to the section that drops down to the main frame.

Doug

 

[dwall174]

With your layout now, you are forcing virtually all the load onto the "tongue" of 5th wheel.

That's where my 8 yrs. of driving a tractor trailer come in to play! Knowing how & where to place the load to balance out the weight to the trailer & the truck.

Doug

 

[CNGsaves]

Cool, all makes sense when we know your intended use is hauling small compact, but heavy items. Also great planning that it will fit in your shop!!

Keep the pics coming, and you've got to come up with "brand" name of this specialty trailer . . . . . . maybe . . . . .
. . . . . . . .. . . . Wall's Machine Transport Express !!

 

[koditten]

now that I know you will be hauling stuff with concentrated foot print, you better make the spacing closer together.

 

[dwall174]

Cool, all makes sense when we know your intended use is hauling small compact, but heavy items. Also great planning that it will fit in your shop!!

My "Achilles-Heel" is a industral surplus outlet near Cleveland, OH. HGR
I go there to pick-up old woodworking/metalworking machines & then I clean them up & sell or trade them for other equipment.

Being able to get the trailer into the garage helps out a lot! I'll normally get back from one of these machine runs later in the evening, So I can just park the trailer in the garage for the night then un-load it in the morning. The same works out with equipment going out, I can load the trailer up the day before then head out early the next morning.

Doug

 

[dwall174]

Keep the pics coming, and you've got to come up with "brand" name of this specialty trailer . . . . . . maybe . . . . .
. . . . . . . .. . . . Wall's Machine Transport Express !!

A slang term for old cast iron machines is "Arn" and I have at times referred to my pick-up truck as a Arn-Hauler! I suppose I could name the trailer something like "Arn-Hauler 2"
Here's a pic of a 1200lb. load I took down to Paducah, KY.


Doug