5'x8' Plywood Popup Trailer

[daverbmxer]

I originally posted this on a Suzuki forum that I frequent, but I didn't get a lot of responses there. So I figured I would try here. If I by chance mention something below that doesn't quite make sense it's probably because I said it on the other forum but didn't add it into this post. I'll do my best to fill in the gaps.

I want to build a plywood pop up on a 5x8 utility trailer. It will be pulled by my 60 horsepower Suzuki Samurai, so being light weight and having a small profile into the wind are very important. I will want to carry 2 motorcycles, a DR350 and likely a TS250. Sleeping for 2 is above the motorcycles. Its purpose will be to get pulled from eastern North Dakota to British Columbia, about 1500 miles one way. So in 2 weeks it could have close to 4,000 miles put on it. It will get pulled 95% of the time on paved roads, but some gravel roads with washboard and small rocks. It's not really a true "expedition" trailer. More of a trailer to get the bikes to somewhere to ride, and somewhere to come back to and cook at and sleep in. I've done tent camping a couple years, but I'm uncomfortable sleeping in grizzly bear country. This seems much safer!

I checked out trailers a couple days ago and think I found the trailer I want. It's a BigTex 5x8'. $599 brand new with no tax. Weighs 380 lbs, has a tubular upper frame, 4 tie down points, Dexter EZ Lube axle. It only has 12" wheels but it should be ok for the speeds I go. I believe it has a 2,000 lb. axle with a 1500 GVWR.

Here's a sketch I've been working on. It looks like I would need a lot bigger trailer, but I have drawn everything to scale it and seems to work out. I think I've thought of most things on it, but some of them aren't really drawn. The top roof lowers from the position shown to a couple inches below the height of a stock Samurai. It is also not really any wider.

As for materials, I want to keep it as light as possible. I'm not sure these thicknesses are ideal, but I was thinking of using 3/8" plywood for the lower level wall, and 1/4" for the upper walls except for the front which would be 3/8" because of the force of wind. 1/2" plywood floor over the expanded steel. 3/8" plywood roof. As for the square steel tube, I am not sure of the thickness yet. But I think 1" square tube for the lower level, which will have 3/4" tube slide into it.

When the roof is lowered, the insides of the 2 bunks sit 3" lower, leaving a bit of a gap between them. I will use a wooden stick or PVC pipe to push up on the center of the roof and spring loaded pins will pop in on the corners once the hole in the 3/4" tube slides up to them. There is also a C channel piece at the tail to keep the upper wall in place. There is a 3" overlap between upper and lower walls, and I think I will use the adhesive backed hard top sealer foam to try and keep mosquitoes out.

3 windows 36" by 18" made of plexi glass probably 1/4" thick, that will not be seen when the trailer is being towed, it will also hide what is in the trailer. The rear door's top bit folds down on the outward side. It has a short "ladder" to get directly up to the bunks without having to go in to the lower level which would be nearly impossible if the motorcycles are in there. When the top part of the door is upright, it is held in place by something similar to a door bolt that I can make up.

If it's a rainy day or something, I can hang out inside and stand up, the roof is somewhere around 6'6" when extended and the bunks are stored up. The pivot point for the bunks is the top part of the lower main wall. The cable is attached to the upper point on the upper wall. The inside ladder folds up under the left bunk, and can only be used if the motorcycles are not in there. Being as how I'm 6'2" and the trailer is only an 8', minus the tube thickness and what not, I probably wouldn't have enough space to get my fat *** up a ladder and onto the bunk. It was around 18" if the ladder were on the longer bunk side. So I moved it to the shorter bunk side, which is a 5'10" bunk, and gives me about 24" to get onto the bunk. Should be enough room to clear knees and what not.

I think I went a bit overboard on all the bracing, but I'm planning on using pretty thin wall tube. 1/8" maybe? 1" tube on the bottom, 3/4" above as I said. I did a very rough calculation and figured it would be about 120ish lbs of steel tube.

So that's my virtual prototype. It's not really done, but I think the main idea is there. I've been working on it here and there for the last few days and that's what I came up with anyway.

I have been told a couple times that I should have trailer brakes on it. The trailer all loaded up will probably be around 1500 lbs. My Samurai only weighs 2200 lbs. I'm realize that is close to it's own weight, but I am very aware of steep highway descents and how to deal with them. I won't be going down any steep forestry roads. I'm kind of on the fence about needing the brakes, what do you think?

Thoughts on it all?

I have some other ideas that I kind of jotted down that I would like to implement in it.

2 of these 220 lumen LED dome lights.
http://www.superbrightleds.com/moreinfo/dome-lights/round-dome-light-fixture-with-3-position-switch/1227/2873/

A shelf/table on the inside of the door, 32" or so off the ground that folds up to the door.

12 volt deep cycle battery, perhaps mounted on the hitch in a battery box. I think I would like to run dedicated 4 gauge wire for the positive and negative to it to keep it charged. When I park it for the day I would disconnect it at the hitch. Would an Anderson plug be best? The battery will power a couple small inverters. I have a 500 watt and a 150 watt, along with the 2 dome lights.

2 motorcycle chocks bolted to the floor, with large washers on the back side of the plywood and expanded steel.

Fuel can mounted outside on the tongue to fill motorcycles or for more range on the Samurai.

Vent that allows gasoline fumes to be sucked out at highway speed.

12 volt fan to cool it down a bit before sleeping.

Attachment hooks for a tarp on the side. Poles can be stored inside in a PVC pipe at roof height.

Does this sound doable? Or is it kind of silly and going to be a pain to use?

 

[jkce72]

Are you building this for just this one trip to BC ? I think your Samurai will hate you for it. I feel it will have a hard time towing this espeacially up a grade or against a headwind. Have you thought of just building a raising platform you could put a RTT on or even a regular tent? Would be a lot lighter with better aerodynamics. I would definately have brakes on the trailer also.

 

[mhiscox]

I think your Samurai will hate you for it.

I know that my Samurai, as sweet running as it was, would have hated me. Not so much just cruising down the freeway, but throw in some grades, and some headwinds, and some headwinds on grades, and the whole thing seems a bridge too far.

And I worry that you're going to suck fuel like crazy, and the range with a stock tank isn't that great to begin with. Plus there's the issue of getting the weight distribution right so that the trailer tow well, which isn't going to be easy with a short little trailer.

Not that I don't think the trailer sounds cool, and it sounds like you've been thoughtful about it. I, for one, would like to see you build it. But even being as lightweight and low-slung as you can make it, I still think you've only got about half the horsepower you'd need. Jeep Wrangler? That'd work. 60 or 66 horsepower Samurai? Not a given, I'm afraid.

One way to find out, though. Keep us posted.

 

[daverbmxer]

Are you building this for just this one trip to BC ? I think your Samurai will hate you for it. I feel it will have a hard time towing this espeacially up a grade or against a headwind. Have you thought of just building a raising platform you could put a RTT on or even a regular tent? Would be a lot lighter with better aerodynamics. I would definately have brakes on the trailer also.

I'm not sure how long I'll use it. A few years though I would think. Probably at least 2 or 3 uses to B.C. as a minimum as long as it works well. Also a bit more local stuff. I'd probably use it a few times a year to take the bike to a place where I can ride it and stay the night, ride some more and head back. I know a couple places that are about 250 miles away. I thought about using a RTT, but they are expensive and not overly compact. I like the idea of being able to lock my stuff up in it while I'm away with the motorcycle and having a dry place to come back to if it decides to rain.

I know that my Samurai, as sweet running as it was, would have hated me. Not so much just cruising down the freeway, but throw in some grades, and some headwinds, and some headwinds on grades, and the whole thing seems a bridge too far.

And I worry that you're going to suck fuel like crazy, and the range with a stock tank isn't that great to begin with. Plus there's the issue of getting the weight distribution right so that the trailer tow well, which isn't going to be easy with a short little trailer.

Not that I don't think the trailer sounds cool, and it sounds like you've been thoughtful about it. I, for one, would like to see you build it. But even being as lightweight and low-slung as you can make it, I still think you've only got about half the horsepower you'd need. Jeep Wrangler? That'd work. 60 or 66 horsepower Samurai? Not a given, I'm afraid.

One way to find out, though. Keep us posted.

When I picked up my DR350 I rented a U-Haul 5x9 trailer, non enclosed. It was 1360 lbs empty according to the sticker on it, with a 300 lb. bike on that. My Samurai did great with it, other than swaying a couple times when empty (pretty sure due to worn shocks and springs). I had been getting about 21 or 22 mpg before the trip with no trailer on the highway. With the trailer I averaged 19 mpg. The trailer also had the big ramp that stuck way up into the air. Not bad I figured. I did 60 mph very easily with it in 4th gear. I could have actually used 5th gear, but it took a bit more pedal, so I cruised at 60 mph, 4000 rpm in 4th. But yes I have the stock gas tank.

I thought about the weight distribution, but I think it's about right with the motorcycles basically filling up the whole length of the trailer. There's only about 7" or so left at the back behind the rear tires.

I have a 1.6 16 valve, which puts out almost 100 horsepower still in a donor vehicle. I haven't done a motor swap before, so it's something I'm not excited to do. And besides the DR350, the Samurai is my only vehicle, so I can't really take it out of commission for a month to swap engines. Still, I would like to swap them sometime in the near future.. 2 years or so.

As for the overall height, beside saying that it was about the same height as a stock Samurai, I don't think I said a number. It should be around 71" from the ground to the top of the roof when collapsed. I estimate my Samurai to be about 72/73" tall with the soft top on. And both are pretty much right on 5 feet wide.

 

[nmzj]

Do you have a friend that has a 16' car hauler? If so, borrow it for a couple of hours and tow it around with the samurai. It would probably weigh around 1500lb empty and would give you an idea of performance.

 

[adam25]

What about something like this? A RTT should cut down on trailer weight and a lower profile will give you less wind resistance. This particular tent is sold by http://top-tent.com/tent-units/m-o-a-b-tent-unit(no conection, just like the product) This type of set up would allow you to use the trailer for other stuff when not hualing the bikes.

 

[mhiscox]

I When I picked up my DR350 I rented a U-Haul 5x9 trailer, non enclosed. It was 1360 lbs empty according to the sticker on it, with a 300 lb. bike on that. My Samurai did great with it . . . Not bad I figured. did 60 mph very easily with it in 4th gear. I could have actually used 5th gear, but it took a bit more pedal, so I cruised at 60 mph, 4000 rpm in 4th.

Your results are better than my experiences, but it sounds like you have both a stronger running Samurai and more successful evidence than I do, and that what you've learned is encouraging. The trailer design is nice, so keep us posted as the build goes along.

 

[daverbmxer]

It probably helps that I have a Corolla carburetor and 2" exhaust with a high flow cat. Otherwise stock though. Last night I was trying to picture a convertible canvas approach to it, but it seems like it would be more set up work. Also I don't have any experience working with canvas.