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TL;DR I want to make a high capacity trailer from bamboo to ride around at a desert festival.

  • Bamboo structure (probably 1.5" or 2" major strength lengths, 1" for crosses)
  • Hitch using bamboo & bamboo joints to get it up to a rack or seat post, with one of the varied DIY hitches seen around the internet.
  • simple wheels with high rated weight capacity, or dual wheels
  • simple steel length with clamps on each side of the wheel to mount,
  • similar clamps to mount to the bamboo
  • weight capacity will be 300+ pounds
  • Estimated costs (at the moment) $200-$250 just for the trailer structure & seat location, and budgeting for mistakes)

Long version:

I'm seriously considering a heavy duty bike trailer for this year at Burning Man (those who don't know, giant arts/community festival in the middle of the desert, so very flat). I'm planning on having a large capacity 36v battery pack as I'm going to get an electric front-wheel conversion kit, and I want plenty of power (plus for lighting & such). So if I go for 20 Ah pack, that's something like 40+ pounds. Then on the trailer a small-ish disco ball suspended off the back with lights for at night. And another 12v battery for all the lights. And a small lockable storage space for stuff. And then a seat for someone on it. So, all told, plan on 300 pound capacity.

Searching around the net (both here and elsewhere), I think I've settled on bamboo framing & structure for it's strength, lightweight, and easy to work with (no welding!).

The two things I'm uncertain of right now, are the hitch & wheels & wheel mounts.

Hitch, I can do something fairly simple to attach it to a rear rack or even seat post.

Wheels and wheel mount is more complicated. I've seen quite a few people have success with 20" BMX style wheels but I'm trying to keep costs somewhat down. Or maybe something like plastic 20" wheels or 24" MTB wheels from Northern tool. As an alternative, use a much lower rated wheel in 16 or 20 inch, but go dually, so 2 wheels on each side. For mounting, seems like I could even just get a length of steel from Home Depot in the right OD, cut it to length, and put some clamp thingies onto it to mount the wheel (which includes bearings) and drill a hole in the bamboo and do the same to hold it in place.

It's very flat terrain with semi-formed dirt roads, not going to be going very fast (maybe 10mph) does what I've said above seem doable?

Móż
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Drizzt321
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  • Consider that a standard medium-weight bicycle can easily handle a 250-pound rider -- you don't really need super heavy-duty wheels, just nothing too lightweight. And I've seen bamboo bikes and they seem to work. You do need to study up on the construction techniques, though. – Daniel R Hicks Jun 23 '14 at 21:36
  • Also see existing question: http://bicycles.stackexchange.com/questions/1256/how-to-make-a-cargo-trailer – Móż Jun 23 '14 at 22:44
  • http://www.scribd.com/doc/24688327/A-Long-Term-Survival-Guide-How-to-Make-Bamboo-Joints has some great bamboo joins, and might even mean I don't need any squaring ropes on the trailer. Seen that other trailer link. Gives some of what I'm needing, but not all. And I included everything I need just to be complete. – Drizzt321 Jun 23 '14 at 23:55
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    @Drizzt321 we encourage people to ask one question at a time, and put some effort into asking clear questions. Your infodump makes it hard to write effective answers. Saying "what wheels should I use and how should I mount them" would be easier to deal with using the StackExchange format. I'd be happy to split my answer below into one per actual question if you want to work out what you actually want answers to. – Móż Jun 24 '14 at 00:43

1 Answers1

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It's not too hard to build a trailer that will handle 300lbs / 150kg, but moving the trailer and staying on the bike in front of it are very different problems.

First, moving the weight. The playa is not smooth, so you're going to need more force than you might expect just to make it move. But since you'll be going slowly you can simply gear down to deal with that. It will help if you have bigger wheels and fatter tyres, so the 24" wheels would IMO be a better option. Those are not as strong when dealing with side loads, but again you're not going fast so the big problem will be people jumping on the trailer rather than fast cornering. Try to load the trailer so it's not inviting to climb onto.

Second, staying on the bike. The simple part is balancing at low speed. If your bike is geared low enough that should be doable, I'd put the seat down so you can put feet on the ground easily and stand to pedal if you need to. The more difficult part is when one wheel hits a bump or pothole and the 150kg trailer decides to throw you sideways. The trailer might also be able to lift your rear wheel off the ground, at which point you're going to fall over. The other obvious route to the ground is someone stepping onto the back of trailer. You can reduce that problem by putting a bit of weight on the back of the bike - maybe put your battery pack there. That will also help with traction, especially if you're standing up to pedal.

If you can mount to one axle of the bike you'll be more stable. The higher up the attachment point on the bike the better leverage the trailer has to push you sideways. Ideally the hitch would be below the axle, and with a 26" wheel mountain bike doing the towing and 24" wheels on the trailer that will also help make the trailer level. Even dropping it an inch or two will help.

Hitch

If you can get access to a welder/someone to weld for you, that spring-and-chain hitch is very robust and unlikely to break or fail. It's pretty easy to make and if you prep it there's only 4 or 5 small welds to complete it.

But for a week of BM you can probably get away with just about anything. Even just cutting up a truck inner tube to make giant rubber bands and using them to tie a flexible lashing on the rear rack would probably work (test it well before you go, because if it doesn't work on site you're going to be grumpy).

Wheels

I think you underestimate the cheap wheels found on kids bikes. For a couple of weeks with 100kg on them, most 20" wheels will do fine. And kids bikes are often thrown away, so you can probably get them very cheaply. You will pay more for decent tyres (or a supply of puncture repair kits and tubes, if you decide to spend your time fixing punctures instead).

I think the main issue you're going to have is the dropout area. You need to distribute the axle load along the bamboo somehow, so it might be worth using MTB front forks on the wheels (running horizontally) as the attachment points for your lashing. If you use "recycled" kids bikes just cut the forks off at the fork crown, or even leave the steerer tube in place. That way you have a fairly long section to lash to (albeit all the load is at one end.

Design

I suggest a basic design like my megatrailer, scaled to fit your requirements. You could lash that up with bamboo, the main addition will be cross bracing of the bed so it doesn't turn into a non-rectangular parallelogram (wire or rope would also work). I've seen this rough design made of lashed bamboo before and it seemed to work.

megatrailer

A chariot design would also work - make the towing arm 2-4 metres long to reduce the forces at the bike end of it. That would simplify everything except getting it to the event. The more I think about that idea the more I like it. You can just use 2-3 lengths of thick bamboo as the towing arm, strap the front end to your bike rack and even just run one length down each side of the trailer. If you did that you'd want 4-6m lengths of bamboo, but it would look quite cool IMO.

Móż
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  • I hadn't considered leverage forces for up/down bouncing of the cart on the bike, especially rear wheel. I might try and work out one of rear axle type hitches. Perhaps the battery pack should mount rather forward of the trailer balance point to help with that. As for getting going, well, that's what the electric motor will help with :) – Drizzt321 Jun 23 '14 at 23:11
  • If you have a person on the trailer it gets harder because they move. The problem is that too much weight on the hitch is also problematic, partly because then side forces are more likely to damage your rear wheel (instead of the tyre sliding sideways the wheel buckles) – Móż Jun 23 '14 at 23:28
  • I was about to ask about dual hitch (one on each side), but then I realized that'd just be silly. However, what about doing one of the hitches that comes off of both sides and meets behind the wheel which the trailer then attaches to? – Drizzt321 Jun 23 '14 at 23:32
  • The Bob hitch? Sure, if you have a welder. They have a longer lever arm for turning than you really want, but they're pretty easy to weld up. – Móż Jun 23 '14 at 23:34