Exacting Specs Trailer Build

[elsensei]

I have an Eezi-Awn RTT that I bought because my buddy Jerrod has one and we'd used it all over southern California and deep into Baja. In my book, definitely the way to go.

Craigslist yielded an inexpensive used shell for my 01 tacoma, and I fabbed up a simple internal frame for the shell itself and mounted the tent to the top of the shell. I have an overhead hoist to haul the shell+tent off the truck and chains hanging from the ceiling of my shop to secure it in place. That all works well but my biggest gripe is that with the tent on my truck, once I reach camp, I'm stuck. Obviously I can't go anywhere without completely breaking camp. I put up with that for a couple years and then finally decided to do something about it.

I go to the desert quite a bit during the season and had acquired 3 quads plus a tandem axle trailer to haul those plus all my camping gear. It worked pretty well, lower shell onto truck, bolt it up, hitch up trailer and go...but the trailer is on it's own lift up and out of the way so that was the first thing that had to go. Sold, for $100 less than I paid for it 5 years ago. God bless Craigslist.

One of the quads had been my ex-wife's and seeing that thing reminded me of that miserable tart...so that was the next to go. Out of sight, out of mind.

Next up: Specifications and criteria for the build.

 

[elsensei]

specs.

I spent a couple days on this forum, checking out all the cool builds, seeing what works and what doesn't and thought long and hard about this build before doing anything. Here's my list of requirements and specs in no particular order.

Trailer has to fit on my storage lift with both remaining quads adjacent to it. Therefore, it can be a maximum of 9 feet long.

In order to get the best possible gas mileage, the overall height including RTT and storage rack can be no more than 6 feet which is the height of the cab of my Tacoma.

Maximum height with fully compressed suspension 69 inches, in order to clearance the ceiling when on the lift with the lift fully elevated.

Height of tent to be low enough that I can remove the cover and set it up without having to climb on the trailer.

Height of bottom of tent when opened to be no less than 6'5". I'm 6'2" and wearing hiking boots on rough terrain, I just want to be able to walk under the tent overhang without whacking my head.

(these two seem to be contradictory, but I have a solution.)

Flat topped squarish wheelwells able to be stood upon in case I do need to get up on top.

12V refrigerator/freezer. No more dealing with ice. I have a small fridge that runs on propane and without ice taking up a bunch of space and ruining everything, I was able to take food for myself and a girlfriend on a baja surf trip for something like 8 days. With a serious 12V fridge with a compressor, I can dispense with propane altogether.

Height of bottom of tent when opened to be no less than 6'5". I'm 6'2" and wearing hiking boots on rough terrain, I just want to be able to walk under the tent overhang without whacking my head.

Trailer to have track of 69", same as the truck so where the truck can go, trailer can go. Also this is the minimum width to fit on the lift.

Wheels and tires the same as those on the truck, for aesthetics and practicality. BFG TAKOs on 6x5.5 sequoia wheels means I only need to carry a single spare for 6 wheels.

Suspension utilizing independent trailing arms, airbags, shocks and bumpstops. Independent arms to be able to go 80MPH down the North Road to Scorpion Bay in Baja, bumpstops in case a bag fails, I want to be able to keep going albeit more slowly.

Integrated water and fuel storage to save on schlepping bulky cans back and forth. Store 20 gallons of water and 15 gallons of fuel.

Integrated compressed air storage.

12V and 110 electrical supply.

Electric brakes so the trailer doesn't pass me on a slippery slope.

Surfboard storage.

Serious trailer levelers so the thing will be super stable even when not connected to the truck.

Weight down low and forward.

Multiaxis coupler.

Good looks and ************ functionality.


That's about all for now. Build pictures coming next.

 

[Wright]

Interesting, Subscribed.

 

[elsensei]

plans

After thinking about all this, I downloaded Google Sketchup. What a great program, especially for the price. With this I designed the trailing arms and the rudiments of the frame, and then figured out where the fridge would go, etc. Of course not everything is coming out exactly to plan as you make adjustments as you go, but overall I'd recommend that program to anyone taking on something like this. Three angles:

...you'll see them once sugarsync has finished uploading...

 

[elsensei]

frame layout

The frame is made out of 2x3 steel. I have a buddy who works at a metal supply so i get a decent price on this stuff. My idea is to use the frame itself as air storage. By my calculations, the sealed frame will have an internal volume of 2500 cubic inches, or almost 11 gallons. Pump that up to 8-10 atmospheres and you've got a decent amount of stored energy and no need to carry a separate 2 gallon air storage tank. Plus, the strength walls of the frame greatly exceed anything you'd see in a low-pressure storage tank. The only difficult part ios sealing up all the welds pressurized-air-tight. Easier said than done.

Wheels I found on Craigslist, had to pay 325 for 4 and only needed 2...but I sold 1 already for $100 and the other one will sell in time. Also, I thought I might use these coil spring I had lying around, but then chose airbags instead once I figured out I'd want the adjustability to fit the trailer on the lift.

Here's most of the frame welded together. It took some time to perforate the crosspieces and get everything lined up but it turned out pretty good. I think.

 

[elsensei]

For the tongue, i was originally going to work with a standard triangle. But then I found a pretty decent tongue box on sale at harbor freight and decided to use it. I always say if you can't build it better or cheaper, you might as well buy it. But to attain the exact angle necessitated a widening of the tongue, hence the additional pieces you see at the front of the trailer frame.

Here's a couple shots of where the box will mount on the frame:

The box will hold the deep cycle battery and inverters and a few other odds and ends I'm certain.

speaking of harbor freight-they also had a 1000 lb capacity swingaway jack for 24 bucks, and a pretty heavy duty all terrain tire on sale so I bought them both, cut off the dinky trailer jack wheel and welded on a bracket holding the allterrain tire.

next up: suspension

 

[elsensei]

frame plus arms and wheels.

To make fabrication a little easier, I managed to find 6x 5.5 hubs with electric brakes already setup for a square axle instead of round. 5200 lb capacity is what they're rated for, apparently nothing lighter duty is available in a square tube.

Once all that was put together, offroad warehouse had bushed steel tubing with nuts/bolts/washers already setup for $20 apiece and I used those for the trailing arms. I did drill each steel tube and thread in a zerk fitting to make the bushings last longer.

Once that was done, I trued up the solid axle, tacked the arms in place, welded them top bottom and sides, then took a sawzall to the center section of the axle and presto! independent arms.

This pic is right after I flipped the frame over. Doing that in limited space by yourself with heavy BFG's already mounted on arms flopping back and forth is a bit of a thrill.

 

[elsensei]

airbags

An ebay seller had 2600lb capacity airbags on sale so I bought a couple. They have about 6 or 7 inches of travel from flat to full extension. They have a single bolt hole in the bottom plate and dual holes in the top plate. I welded in crossbraces on the trailing arms then cut a crosspiece to mount the bags to at the top of the frame. A little persuading with a pipe wrench to get a neutral angle and then stitched them up all the way around.

The lower mount for the bags is a piece of allthread welded into a 1/4" steel plate, while above I drilled 4 holes through the top of the crosspiece to be able to access the bolt heads should a bag fail or otherwise need to be replaced.

 

[elsensei]

bumpstops and shocks

of course, it wouldn't be a baja trip if something didn't go wrong, and in case of catastrophic airbag failure I decided to mount some solid block urethane bumpstops at two points on each trailing arms. Also, when the air is out of the bags for storing the trailer, the bumpstops will carry the pressure of the weight of the trailer.

Also, Edelbrock is blowing out their shocks. Gas charged, inertia active, good quality, were $60-70 dollars apiece on a discounted, buy 3 get one free sale for 4 for 44 bucks! The ones I got were supposed to be for a lowered dodge durango but of course you can mount them wherever you want. I set these up so they'd not top out or bottom out across the swing of the trailing arm.

They actually work pretty well, even at that angle. When I disconnect the hose form the bags, allowing them to collapse completely, the shock instantly engages and maintains most of the frame height. Whereas when you slowly deflate the bag, the shock "allows" the frame to gently fall. It'll be interesting to see how they act offroad.

 

[elsensei]

wheel wells

Next up were wheel covers. Since a lot of camping is about "thing management" as a good friend of mine says, you can't have enough flat surfaces on a camping trailer. Also, I wanted something flat-topped and sturdy to be able to be stood upon. I used .190 thickness aluminum diamond plate, cut 6 individual pieces for each wheelwell/fender/deck and tigged them all together. Then to maintain the airtight-ness of the frame, I tigwelded short bolts on the top of the frame, drilled holes in the aluminum to accept the bolts and cranked it all down with acorn nuts and lockwashers. I can stand on the wheelwells just as they are, with no steel backing, and they don't budge.

There's aluminum decking in there too, but that is for another post.

 

[grimbo]

I really need to stop checking these threads out. They give me ideas and then I remember I don't have the skills to make it happen. Really digging the idea and especially the execution thus far

 

[Wright]

+1 on what Grimbo said!

 

[elsensei]

coupler and air system...

For a coupler, I was looking at the locknroll and the maxcoupler...I even thought about fabbing my own using some oversize heim joints...But after pricing what quality heims of that size cost plus factoring in time vs. the quality of professional made, I decided on the maxcoupler.

Here's a shot of the total travel available with the airbags and bumpstops...one bag inflated, one deflated:

And here's a shot of the pivots and arms while I was setting up the shock mounts:

I spent a few hours yesterday with 2 welders and a bottle of soap solution, tracking down every pinhole leak in the frame. I thought I had them all nailed down but last night before going to bed I pumped it up to 80PSI and found 2 more tiny ones. Luckily they are in easily accessible areas so I'll have those fixed this morning. I'm using two quick-disconnects to on and offload air from the frame, pics of that in a bit...

 

[java]

wow impressive work. garage looks like it has lot of toys too.....

 

[Curtis in Texas]

Woa!

Air bottles are round for a reason. Although it looks like it would be a good idea, square tubing will not hold much pressure before it blows out at the corners and seams. If you want something to run a set of ARB's at less than 50 psi they might work for that, but forget pumping them up to the 250 psi range for tires and such. When a seam blows it could blow like a bomb! Spitting pieces and parts away at high speed is a real possibility!

But I should point out here internal air pressure will bulge out the walls unless they are really thick wall tuff that will be impractical for a trailer build.

Moisture will be your next big obstacle. Air will always contain H2O molecules in it. So rust will start as soon as you put air to it. Rust will start to eat away at the inside and the life cycle if the frame will be greatly reduced. That is unless you are using an alloy steel that will not rust. But, that would be an expensive trailer.

Even if you were to be able to seal the entire inside of the tubing with a gas or water tank sealer it will never hold up well enough to contain enough compressed air volume to air up a trailer tire.

Best use of that inside tubing for fliuds will be to seal coat it with a tank sealer and use it as an emergency water storage or non flammable fluid storage, not under pressure.

Do not put gasoline inside the tubing at anytime, or you will have an instant bomb at the first spark. Even if you drain the gas, the vapors will be a disaster looking for a place to happen. If you induce flammables inside the tubing you may as well start over. You would never weld on an old gas can would you?

Now if your frame were made out of round tubing and the welds were done with certified welding standards I would say "No Problem"! Just remember pressure in squared off corners is not a strong joint. High pressure tubing corners are always curved and never welded on the corners. Even end caps are round for a reason.

Safety should be your main concern and if it were me, I'd utilize the inner space for storage of tent poles, ropes, tools and hoses.

I did build a square tubing bumper for my van back in my teens to be used as air storage for under 30 psi for airing up my motorcycles and it was always springing leaks at the corners.
So, I made another one out of round tubing with domed caps and it worked much better.

Nice build so far!
Wish my shop was a clean as your garage!