ABB's Bike Trailer

[atomicbartbeans]

http://i26.tinypic.com/24wzhwn.png (http://i26.tinypic.com/24ywep1.png)
(touch to make it bigger)
(that's what he said)

Yeah. I had been wanting to build a simple bike trailer for a while, and somehow about an hour ago my mind was like "well why not take it further, giving you the bicycle motorhome construction project of your dreams?"

The picture is just a rough visualization. Here are my goals...

For those of you who think this is too big/heavy to be pulled by a bike, you're simply wrong (http://www.bikesatwork.com/hauling-cargo-by-bike/hpv-cargo-capacity.html).
large enough inside to sleep one adult - i was thinking 6.5'x4' for the base... high enough inside to accommodate chillaxing while sitting up
fully enclosed and rain-tight
safe enough to tow with a bicycle on public roads - tail and side lights, reflectors, etc
freestanding sans bicycle
window on front and each side, locking door in rear, some means to let in air while keeping door closed
12V electrical system to power LED/CFL lighting (both inside and out), ventilation fans (probably PC case fans), stereo with iPod input - possible inclusion of a small 120V inverter, maybe even PV array wired in series on the roof for charging
sort of lightweight (50 pounds? 100 pounds? who knows. I only weigh about 125 and I'm not at all averse to pulling something heavy)
use of as many recycled/second-hand materials as possible - for the purposes of this project I'm acting as if I'm nearly broke


I was thinking a wood frame of 1x2s and aluminum sheeting for the exterior. I think that will make it super easy (and hopefully cheap) to build. The sheet metal could be scavenged from an old above-ground pool. Windows could be made with plexiglas. I already have a set of 18"ish wheels in great shape, scavenged from my early childhood mountain bike.

How neat would it be to go on a trip with one of these? The spacious (compared to a typical bicycle trailer) interior would allow you to store everything you need for camping, all without the hassle of loading up a touring bike. You could even stick your friends in (as long as they sit near the axle). Personally, I'd also just haul it around town to look badass.

Incidentally, my research has shown no current or pending legislation regarding restrictions on what one may pull behind a bicycle. I don't think it would be much wider than one of those tricycle-bikes. I'd love advice and input, as this project is unlike anything I've done before - actually, AFAIK unlike anything anyone has done before.

[atomicbartbeans]

Well, I just got back from Bargain Outlet with some horrifically cheap 2x4s, 1x3s, and peanut M&Ms - I'll update with frame construction pics.

[709]

If you're going with flexible aluminum sheeting, why not make the front a little more aerodynamic? Even shaping it into a simple point (ala a boat's bow) would probably help greatly pedaling against a headwind.

[Brad]

Well, I just got back from Bargain Outlet with some horrifically cheap 2x4s, 1x3s, and peanut M&Ms - I'll update with frame construction pics.
If you're looking to save on a lot of weight, you might want to try polystyrene (plastic) instead of aluminum for the outer shell. I've been using polystyrene in the above project and have been surprised by how strong it can be when properly supported and cemented. It'll certainly be more fragile than aluminum, but that'll only really be an issue if you're in a collision.

I got my sheets from http://www.usplastic.com, for what it's worth. This type (http://www.usplastic.com/catalog/product.asp?catalog%5Fname=USPlastic&category%5Fname=76&product%5Fid=3008), specifically.

[Dorian Gray]

Crazy project, atomicbartbeans! :)

If you're going with flexible aluminum sheeting, why not make the front a little more aerodynamic? Even shaping it into a simple point (ala a boat's bow) would probably help greatly pedaling against a headwind.
Good idea. Even more important is the aerodynamics of the rear. A flat rear will cause eddies that consume lots of energy in their formation: energy that comes from your quads! A flat front won't cause nearly as many or as large eddies, and your body will have already messed up (and accelerated) the air hitting the front. Both front and rear are important, but if you have to choose one, go with the rear. Perhaps put the door on the front instead of the rear to permit this?

Also, make it as low and narrow as you think you can bear!

[Banana]

Dorian Gray,

I'm a idiot at aerodynamics- I find it somewhat counterintuitive that rear would be more important than front as I always think of air hitting the front hard but leaves a bit of vacuum in the rear area. I'm just not understanding how eddies would drag on the object?

[pscates2.0]

I was wondering about that, but that's how you always see these things. I don't know much about aerodynamics and speed design, but you always see such thing tapering toward the trailing end. And it seems like you could get it lower (sitting up at the waist, you're not much over 3" feet tall...and if it was more of a pillow-propped "raise", you could get away with a trailer that was only about three feet tall?

Maybe a wedge/tear shape, with the skinniest part toward the back? And as low/small as possible. Would probably be much easier to deal with. You don't need a "has everything luxury RV" ...just a place to crash, stay warm and dry, etc? I'd go smaller/sleeker, rather than a big 6' x 4' "cube".

Slinging things around a bit in Illustrator (http://homepage.mac.com/pscates/mockups/trailer.gif) (anything for an excuse to launch it) :)

I think of those tapered/wedged soapbox racer cars (http://blog.makezine.com/img413_1482.jpg), where things narrow and come down. You could provide a really simple skeleton and easily tack the sheet aluminum to it?

BTW, I saw this (http://blog.makezine.com/med_wagon_skis.jpg) at the soapbox link above...can you say "sled o' death"? :D

[Artap99]

BTW, I saw this (http://blog.makezine.com/med_wagon_skis.jpg) at the soapbox link above...can you say "sled o' death"? :D

I don't know...that kid seems pretty happy :)

[709]

abb, your project and the subsequent ideas made my mind drift into fantasies of living in an Airstream (I have these once in a while), so I meandered over to their site to daydream a little bit...

I thought you'd appreciate the logo on their homepage (http://www.airstream.com/):

http://www.davidlegatt.com/images/albums/userpics/10002/AirstreamLogo.jpg

:D

[atomicbartbeans]

Crazy project, atomicbartbeans! :)
Thanks! :D
http://www.davidlegatt.com/images/albums/userpics/10002/AirstreamLogo.jpg
After looking on their site for a few minutes, I sadly couldn't find any bicycle trailers. :( I guess it's a marketing gimmick to illustrate the ease of towing one. Cool nonetheless!
If you're looking to save on a lot of weight, you might want to try polystyrene (plastic) instead of aluminum for the outer shell.
Thanks for the info, but it's already taken care of - a friend had a dismantled old above-ground pool in his backyard, and he gladly gave me the aluminum wall - it's about 65 feet long (rolled up right now of course) and 5 feet high, so I have all the siding/roofing I need!

Also, make it as low and narrow as you think you can bear!
I was wondering about that, but that's how you always see these things. I don't know much about aerodynamics and speed design, but you always see such thing tapering toward the trailing end. And it seems like you could get it lower (sitting up at the waist, you're not much over 3" feet tall...and if it was more of a pillow-propped "raise", you could get away with a trailer that was only about three feet tall?

Maybe a wedge/tear shape, with the skinniest part toward the back? And as low/small as possible. Would probably be much easier to deal with. You don't need a "has everything luxury RV" ...just a place to crash, stay warm and dry, etc? I'd go smaller/sleeker, rather than a big 6' x 4' "cube".

Slinging things around a bit in Illustrator (http://homepage.mac.com/pscates/mockups/trailer.gif) (anything for an excuse to launch it) :)

I think of those tapered/wedged soapbox racer cars (http://blog.makezine.com/img413_1482.jpg), where things narrow and come down. You could provide a really simple skeleton and easily tack the sheet aluminum to it?
Leave it up to you guys to be this crafty. :) Paul, I really love your diagram. I'm still not sure what I'm going to do tapering-wise, but I'm really not building this for speed - the bottom frame (I put it together today) is 7 feet long and 4 feet wide, and I don't really expect to exceed 10-15 mph (or scale any steep hills) considering that it'll already be heavy. Its purpose will be more of a "tow it 10-30 miles for camping trips" deal than long-distance touring. Hence, I don't care a ton about aerodynamics - this is already pretty big, and I'm designing it for plenty of room inside. Nonetheless, some tapering (such as this (http://www.cedargate.com/imgs/misc/camper01.jpg)) couldn't hurt.

Anyhow, the first day of design & construction went very well. Here are some pictures I took (here (http://www.flickr.com/photos/atomicbartbeans/sets/72157605564713804) is the full set on Flickr with bigger versions):

http://farm4.static.flickr.com/3121/2571653345_37e407edc7.jpg

http://farm4.static.flickr.com/3277/2572477228_1d62f37a01.jpg

Yeah, I know it's huge. I kinda want it to be. The steel L-brackets will end up on the bottom, guarding the wood frame from knocks. Of course, I still need to add cross-pieces and mounting points for the wheel brackets; this is only the outer edge.

http://farm4.static.flickr.com/3059/2572478062_369a926882.jpg

http://farm4.static.flickr.com/3087/2572478680_0f31501d7b.jpg

20 inch wheels, and brackets inspired from here (http://howtofixbikes.blogspot.com/2006/07/big-homebuilt-el-cheapo-bicycle-cargo.html). The brackets will be bolted to the frame.

http://farm4.static.flickr.com/3021/2571656181_8e5662c5d6.jpg

Hitch on bicycle - the towing arm will be made of an old bike frame; the end will be an open tube with holes in the top and bottom. The clevis pin (yes, that's really what it's called) will connect the eye bolt to the tube, held in place by the cotter pin. This design, while simple, gives the freedom of movement necessary while making turns.

http://farm4.static.flickr.com/3069/2572480090_9b08f3633e.jpg

Some lumber and square aluminum supports (siding not shown). I still haven't gotten the aluminum decking that my friend also offered me - I'll bring it home tomorrow using the trailer as a flatbed (once I get it together).

My goal for tomorrow is to finish the bottom frame and mount the wheels, construct a towing arm (to the bicycle), and take it for a test spin/materials pickup run. I'll also get a big sheet of plywood for the deck, cut it to size, and screw it down. Then I'll start working on the upper frame - using either 1x3s or those aluminum pieces (I'm leaning towards aluminum because they're hollow in the middle for routing cables), I'll build the wall frames. I'll design it so that the door and windows are mounted directly to the frame, not the siding.

This begs a few other questions...

Where should I mount the wheels - right at the midpoint? Back further?
Exactly where shall I attach the wall frame supports to the bottom frame?
How tall should the interior be?
What shape should I make it - to what degree should it be tapered, and how hard would it be to design a wood frame with such odd angles?
What color should I paint this beast? White enamel or something sexier?

[Yonzie]

Where should I mount the wheels - right at the midpoint? Back further?They should be placed to insure that they will be slightly behind its centre of gravity.
You most definitely don't want them too far forward, since that'll make your rear wheel fly.
Too far back would place all the weight on your rear wheel, so that would be bad as well, although better, of course.

[atomicbartbeans]

Yeah, and since I'll have stuff inside, I can always shift the weight around.

[Bryson]

Thanks! :D
I don't really expect to exceed 10-15 mph (or scale any steep hills) considering that it'll already be heavy. Its purpose will be more of a "tow it 10-30 miles for camping trips" deal than long-distance touring. Hence, I don't care a ton about aerodynamics - this is already pretty big, and I'm designing it for plenty of room inside.


I don't think the tapering would be for the sake of speed: more for the sake of your legs. Even the slightest hill will make dragging this thing significant.

[pscates2.0]

Yeah, I was thinking more along those lines than setting any sort of trailer-towing land speed record... :p

But it looks cool. But it already seems heavy...that wood frame alone has to weigh a bit, doesn't it? :eek:

My stepfather built a neat little "luggage trailer" to tow behind their hot-rod, the yellow '29 Ford coupe he built. He got the trailer built but, unfortunately, wasn't able to get it painted and completely wired/trimmed (the same yellow as the car, flared fenders, etc.) before he unexpectedly passed in late 2004. It's sitting out beside the garage, next to the car, still bare metal...

:(

But it was a teardrop thing, and curvy and rounded (very Airstream-ish, but only about three-feet tall and 5-6 feet long...but it had the nice curved, lowered look of the car, and would've looked awesome riding behind it, with matching paint, chrome trim/accents and a smaller set of similar wheels and tires). It was to hold suitcases, etc. since the car didn't have much interior space (two seats and about 6" of room behind them, if that).

[atomicbartbeans]

Well, day two went a little slower than I thought it would, but I'm very pleased so far.

http://farm4.static.flickr.com/3002/2574086325_c69f59d758.jpg

Tomorrow I'm going to screw in 45° inside corner braces to add sturdiness.

http://farm4.static.flickr.com/3079/2574911148_b005e8ebfd.jpg

The wheels mounted quite well - the brackets seem like they'll take quite a lot of stress. I decided to put them about three inches aft of center - the trailer naturally tips slightly forward when unsupported, which is exactly what I wanted. The entire thing rolls *very* easily (more so than my bike) and probably weighs about 35 pounds right now.

I also acquired plywood to use as a deck - I'll cut out holes for the wheels, which will eventually be completely enclosed in a well.

I also wanted to say that this is the most fun I've had in a really long time - it is amazing watching it come together from a pile of boards and screws, seeing as it's all my design and effort (with the help of a couple friends). Before I started this I wasted a ton of time around here doing not very much - so I guess my advice to those who are bored is to think of something something complex yet plausible that you really want to work on - you'll feel so much better at the end of the day. :)

[atomicbartbeans]

OMG!!1!479

Just took the frame for a ride around the block (which includes a ~150 foot hill; think San Francisco) - it handled like a champ. :)

[709]

That's looking really great. :)

How are you thinking about keeping it level when you're camping? Do you have some sort of 4-corner supports in mind?

[Bryson]

I imagine bike kickstands would do the trick: lightweight, quick, convenient and the real load will be on the wheels, not the stands.

[709]

I was thinking along those lines too. That, or some short EMT pipes he could affix under each corner.

[atomicbartbeans]

I imagine bike kickstands would do the trick: lightweight, quick, convenient and the real load will be on the wheels, not the stands.
I was thinking the same thing (I have a couple lying around) - not sure how sturdy it would be if you sat at one end though.
I was thinking along those lines too. That, or some short EMT pipes he could affix under each corner.
EMT pipes? :confused:

The ideal supports IMO would be four hinged legs that swing up inside the frame for travel, and also have some sort of length adjustment to level the trailer on any terrain.

Anyhow, here's what I did to the frame today:

http://farm4.static.flickr.com/3159/2576338721_24561f3cfc.jpg

It's really really strong - you can stand (even jump) on *any* of those boards without it flexing.

For the test run I clamped on a quick-and-dirty hitch made from aluminum piping - sadly it got a little bent. It did show me that towing it is quite easy - the hill I pulled it up is steeper than any I imagine scaling in normal use, and I had a couple of cinder blocks also clamped on to simulate more weight.

I also got tons of odd looks from people, including cops - my footprint while towing this is about that of a sedan, so it's very noticeable.

Tomorrow I affix the deck - the plywood is all cut, complete with wheel holes. :)

[Brad]

EMT pipes? :confused:
EMT = Electrical Metallic Tubing. It's basically a metal conduit/pipe used for routing wires through buildings. I believe 709 is suggesting you use a short length of pipe standing up lengthwise to support the trailer.

Plastics guy that I am nowadays, I'll suggest that you could also use short segments of PVC. ;) Either should be available for cheap at your local hardware store.

That said... beautiful work so far! :)

[pscates2.0]

How is that not 135lbs. by now? :D

it just seems like it would be. I like those tires!

That would be cool to sleep in, outside at night. I need to do that more...just in my own yard (don't need any of that "wilderness" and "snakes and bears" horseshit). :p

[atomicbartbeans]

How is that not 135lbs. by now? :D
The frame is about 45 pounds now. I'll weigh it tomorrow after attaching the deck. ;)

[Dorian Gray]

Looking great so far, atomicbartbeans.

I find it somewhat counterintuitive that rear would be more important than front as I always think of air hitting the front hard but leaves a bit of vacuum in the rear area. I'm just not understanding how eddies would drag on the object?
Think of it from a conservation-of-energy point of view. Eddies that are swirling (and continue to swirl for many seconds in the slipstream) required energy to get the air moving. That energy had to come from somewhere, and it comes from your forward motion.

The front of a body moving through the air does indeed push air in front of it, causing drag. But the "bit of vacuum" at the rear sucks you back, in addition to its eddymaking properties, causing more drag than the front. That's why aeroplanes often taper to a point at the rear. A road vehicle has practical limitations on length, so fastbacks (http://en.wikipedia.org/wiki/Fastback) are not all the popular. Fastbacks also cause lift at the rear, lightening the weight on the rear wheels and causing less traction, which is obviously undesirable. The Kammback (http://en.wikipedia.org/wiki/Kammback) eliminates some of this lift while shortening the vehicle.

[Fahrenheit]

When you are on the road, aren't you gonna be kinda slow? Cos normally its easy to overtake cyclists who sit to the left (or right in your case), but if you take up the entire width, aren't you going to be a bit of a hazard?

However, its looking awesome! :)

[atomicbartbeans]

Plastics guy that I am nowadays, I'll suggest that you could also use short segments of PVC. ;) Either should be available for cheap at your local hardware store.
PVC would be tits, if I could figure out some kind of ratcheting mechanism to adjust the length.
When you are on the road, aren't you gonna be kinda slow? Cos normally its easy to overtake cyclists who sit to the left (or right in your case), but if you take up the entire width, aren't you going to be a bit of a hazard?
Yeah, a little. I think it's justified by horse-drawn carts though - they're yet larger, slower, and towed not by a determined cyclist but a 1,500-pound animal. And they're still road legal virtually everywhere.

I'll make myself seen by motorists though - I plan to mount one of those reflective triangles that denotes a slow-moving vehicle, along with tail lights for night use. If I find that insufficient, I could get one of these (http://www.amazon.com/Delta-Airzound-Bike-Horn/dp/B000ACAMJC) as well, so I can be the loudest (in addition to widest and slowest) cyclist on the road. :p

Yeah, that makes me sound like a prick - I don't mean to be. From my test run I didn't notice anything to indicate driver irritation, and I wasn't riding any further out than I usually do. The trailer only extends laterally two feet beyond the center of my bicycle, which is only a few inches more than most handlebars. I pedaled around 10-12 MPH on flat ground, which I'm sure will increase as I gain confidence in towing this beast.

Another thing to talk about - I'm having trouble coming up with a sturdy towing arm design. The one I put together had the tendency to twist clockwise (as viewed from the front) with even a slight amount of tongue weight. Anyone have ideas?

[atomicbartbeans]

Hot sauce.

http://farm4.static.flickr.com/3276/2584063061_a0eb59ffc7.jpg

The towing arm is one of those brackets designed to store canoes and such on the wall of your garage - a mere $2.99. It's quite rigid and held onto the frame with two bolts.

I found it sturdy enough to tow my 170 lb. friend around the driveway, and then ride it about 5 miles for a lumber run - I picked up more 1x3s to make the upper frame. I also hit up the dollar store for polyurethane coating and caulk for waterproofing (both really cheap). Weather permitting, I'll start to assemble the upper frame tomorrow morning. :D

[pscates2.0]

That's pretty cool! :D

[Capella]

That looks awesome. :) Looks like it's quite an undertaking, too!

[zsummers]

atomicbartbeans = Pimp.

[Bryson]

I think I have found (via Digg, today) ABB's inspiration:

http://bryson.albassamtheatre.com//ABBcycle.jpg

[Brad]

*BUMP*

The people demand updates, abb!