sunnyboy44

Dear reader,
As the title says, my plan is to build a recumbent bike out of bamboo. Before I go further I will introduce myself as this is my first posting here. I live in New York City, am going to high school, and love to tinker with/build stuff. I started with model soldiers, then started making model planes (still doing so) and now I want to build my own bike. I have minimal knowledge about bike building, although two great guys from my school are already helping me a little, and so I need some place where I can ask a lot of questions and get answers from people who know what they're talking about. All help is much appreciated!

The Bike:
I already have an idea of what I would like to build and it is almost entirely the same as this bamboo recumbent made by Klaus Volkmann:

https://www.youtube.com/watch?v=erxjvLgxULo

The only variation to the design I would purposefully do is lengthening the two bamboo pieces that attach to the back wheel (my lack of bike vocabulary already becoming apparent) so that the seat could be pushed forward a few inches, allowing a rack to be placed over the back wheel.

Questions:
I have a number of them but first and foremost; is this the best design for a bamboo recumbent? I want the bike to be short wheel base (for the small city) and aerodynamic (again I think that a short wheel base helps with this because of the angle of the seat) and able to carry at least my school bag.
2) What should the thickness of the bamboo be? I am cutting it down this weekend from a friends property so the supply isn't a problem. Also, the friends I mentioned before have a blowtorch to heat treat the bamboo.
3) Is my first step to make 1:1 plans on a big piece of paper? If it is how do I go about starting this? Do I need to take my height into consideration?

Curious and excited,

-Sunnyboy44

LWB_guy

Bamboo is a good, strong material. I never saw a bamboo recumbent before I viewed that youtube video you posted. I made a wooden recumbent. It is LWB. I made a luggage rack for the rear end like the one shown on this webpage:
https://www.k3pgp.org/bikerack.htm

Instead of angle aluminum, you can build a rack out of small pieces of bamboo. The back of the bike seat stops at the top of the rear wheel. So you have room to put a bamboo rack behind the rear wheel. Just copy the one shown on the k3pgp webpage using bamboo and figure out how to attach it to the rear wheel and to the bike frame.

You can skip the buckets if you're just carrying a few books -- less than 10 pounds. However, you want to get the weight as low as possible if you want to carry heavy weights--like, for example, a load that weighs as much as four bags of groceries. If the weight is too high above the rear wheel axle, the bike gets top-heavy and wants to fall over whenever you lean to turn.

LWB_guy

Your bike must be built to fit your x-seam. The bike frame should be long enough so that when your foot pushes the pedal to its most forward position, your leg will be fully extended.

The other important consideration is comfort. The seat must be comfortable. You must be sure nothing touches your legs as you pedal.

Good luck.

Allen

It's not the thickness of the bamboo that you need to be concerned with, it's the diameter of the tubes.
You want 2 inch tubes at least.

I've built several bamboo diamond frames and small diameter tubes = a swing set bike.

Google Brano Meres, he has a good how to on the building of his bamboo diamond frame.

3M Scotch weld is a good glue to use
West Systems is an easy to use epoxy system.

Go into the framebuilding section of BF and search for Bamboo.
There are many threads in there started by bamboo builders.

Oh, and buy your bamboo for your first bike from a supplier like Bamboo Hardwoods or Frank's Bamboo.
Their bamboo is from China (so it's aged already and less likely to split).
Fresh bamboo needs a year or so to dry.

sunnyboy44

First, thank you for the advice on the rack LWB_guy, I will keep it in mind for when I get to building that part. I have thought about how I could make a seat but cannot think of anything thats seems like a great idea. How does one go about building a seat?

As for the source of bamboo; I really want to use the bamboo that I get this weekend. Isn't it okay if I just heat treat the fresh bamboo?
I plan on using hemp fiber for the lugs (lugs are the places where the frame sections meet right?) and so far I have found only one source:https://www.rawganique.com/HAfabric.htm Are there other suppliers?
As for the glue/epoxy; I want to be a environmentally smart about this bike as possible, and so I want to avoid fancy chemical mixtures that I don't understand. Is there a glue/epoxy that one can make yourself? I read on wikipedia about "a simple paste made by cooking flour in water." which I will be testing.
Tires: I want to skip the petroleum based tires and buy some nice natural rubber ones. Can you recommend a supplier?
I'm all over the place with my questions right now, but I just need to amass some data to get things started.

Even more curious

-Sunnyboy

LWB_guy

If you wish to avoid "fancy chemical mixtures that I don't understand" and use water-based glue, then don't be surprised when your frame disintegrates when you are riding your bike and it rains.

On the other hand, if your bike to last beyond the next rainfall, then I would also recommend using West brand epoxy. It is what I used for my wooden bike.

There are several kinds of West epoxy you can use: The first kind is resin/hardener. You mix two and half parts resin to one part hardener. It stays workable for 45 minutes, then hardens. You have to clamp the pieces together until the epoxy cures. It takes 24 hours for the epoxy to cure at 70 degrees F. If the temperature drops below 60 degrees F, then the epoxy won't cure. I used 105 hardener/206 resin. When it cures, it is stronger than the wood.

The other kind, which my friend recommended, is G/5 epoxy. You only have to hold the parts together for 5 min. It cures in 5 min. I did not try this because I thought I might not be that quick.

When the epoxy is cured, it can be sanded, drilled, filed -- just like wood.

Allen

Google, "hemp fiber" and you will find handfuls of suppliers.
Aged bamboo is least likely to split. Flame curing helps. Expect splits and charing until you learn your medium.
Flour paste is sufficient for construction paper projects, not for building a bicycle.

BlazingPedals

The bike shown in the video reminds me of a Reynolds T-Bone, only in Bamboo instead of Ti. Best design for a bamboo SWB would be a 'stick bike' like the one shown, or possibly like a Bacchetta-type highracer. IMHO. Keep the frame simple!

It sounds like you're trying to turn this into a 'completely-natural' project. I'd advise against going too organic. Organic glues aren't as strong and don't last. Natural gum tires, if you can even find any, will wear very quickly. Latex tubes, while giving a nice supple ride, lose air quickly. My advice is to only go natural when you can do it without making sacrifices in durability or safety. Go ahead and use hemp wrapping at the joints/lugs, but make sure they're wetted with epoxy. Maybe you can use carbon fiber for the seat, head tube, even dropouts. That way you'd be sequestering the carbon!

sunnyboy44

The cooking flour in water was a stupid idea, but I am not going to abandon the idea of a better glue just yet. I searched around a little and found this article about Caulobacter crescentus, a bacteria, that proves that natural glues have some serious strength.
https://www.physorg.com/news63981444.html
That glue is far from necessary (or available) for a project like this, so I searched a little more and found this article about the findings of Syed Imam at the National Center for Agricultural Utilization Research in Peoria concerning starch-based glues. It explains how the starch-based wood glue is water-resistant, strong and environmentally good compared to the industrial wood adhesives "made entirely from petroleum and natural gas," and including "carcinogenic ingredients" and exposing workers to "formaldehydes and phenolics"(https://news.thomasnet.com/IMT/archiv..._a_natura.html). The article was written in 2002 and if the author was right in his prediction that starch based glues would be available one year later, there should be some available today. Does anyone know of any such glues or know of a place where one could ask for them (glue.com or something along those lines....)?

Blazingpedals- Thank you for your kind input. I am trying to make this project as simple, cheap and clean as possible, and I am willing to make sacrifices. Now the frame; I looked at some Bacchetta highracer bikes and agree that that design is probably a better idea, but am not exactly sure why. The only difference I see is that the two pieces of bamboo that connect to the wheel and main piece under the seat, meet the main bamboo section at a different angle. Will this make securing the three pieces together easier and the seat more reclined resulting in a more aerodynamic profile?
I know my x seam is 45.5 inches, so how would I start designing the bike if I am making it like a stick bike? I also want to use the type of steering system on the Bacchetta (where the steering wheel is right over the wheel) but how much room do I need to have to allow for my knees to bend under it?

-Sunnyboy

BlazingPedals

With a Bacchetta-style stick bike, the stays can be inline with the main tube. The dropouts should stick down below the line several inches, so that the chain can reach all the gears. The relation between the dropouts, chainstays, and idler will (hopefully, if you do it right) keep the chain from hitting the frame - or the fork. Having the chainstays in line with the main tube will make the seat higher, but will make the bottom bracket lower. Overall the riding position will be less extreme. Rich Pinto of Bacchetta seems to think that 28 degrees is the 'sweet spot' for the seat recline on that style of recumbent. I'd probably aim for that. As for dimensions, print out a pic of a Bacchetta and make a 'blueprint.' If it were me, I'd aim for a 46-47" wheelbase and build it up to my measurements from there.

I don't have much experience with 'tweener bar setups. The easiest way would be to use a pivoting stem such as a Terracycles Glide-Flex stem. The riser will probably be 12-18 inches long, and you can put a standard threadless stem on top. Tweener bars go in front of your knees and pull back along the sides.

LWB_guy

If your x-seam is 44.5 inches, add 3 1/8 inch to this to get 47.625 inches. The crank should be 47.625 inches ahead of the place where the seat bottom meets the seat back. At least, that's the way my wooden homebuilt LWB recumbent bike is. My seat back support post makes an angle of 57 degrees relative to horizontal. A straight board goes from my rear wheel support to the bottom of my seat to my crank. This board is tilted upward at 7 degrees from horizontal, so the front end is slightly higher than the rear end.

Your bike's geometry might be different. I recommend that you get big cardboard boxes to cut out templates. You know, refrigerator-sized boxes. Then you can experiment with cut-out cardboard pieces to make sure the geometry is right for you before you start cutting bamboo. All you need is big pieces of cardboard, a razor-knife, and a Sharpie.

LWB_guy

Have you thought about how you would attach the metal parts to the bamboo? The rear wheel axle, the fork, the handlebars ? On my wooden bike, I used angle aluminum. This is aluminum that is bent at a 90-degree angle. It is 1.5 in. wide by 1.5 in. wide by 1/8 in. thick. Easy as wood to cut & drill. Easy to cut with a hack saw too. I'd suggest you try to find some. I realized you could connect the bamboo pieces to one another, and the metal parts to the metal parts, using some kind of natural fiber, like jute or twine. I don't know if that would be strong enough if you hit a pothole, though. Of course, you'd have to be a good knot-maker so it doesn't come loose.

sunnyboy44

I will by making the plan some time this week and then build a 1:1 scale model of the bike and post some pictures. BlazingPedals, you say you don't have much experience with 'tweener bar setups, what other types are there? Are there some major advantages/disadvantages? LWB guy, I want to attach the stays with the main tube by sanding and scoring, gluing them together, wrapping them in hemp fiber and then soaking the joint with epoxy. For the places where metal meets the bamboo I was planning on doing the same; scoring, gluing, wrapping and soaking. Where would/could the angle aluminum that you mentioned be used?
Sorry for the lag in response been busy with school,
-Sunny

chucky

Thanks for this info and thanks to sunny for making this thread and posting that video.

I think I'm gonna make a dual 700c stick bike out of bamboo because it seems well suited for this style and I'm not entirely pleased with the commercial frame options (though I have a commercial frame almost dialed in to use as a sizing reference).

I like the idea of making it with my bare hands from materials that could potentially be grown in my yard. Matches well with my cycling ethos. Maybe I'll even try making a hard shell seat out of steamed balsa.

LWB_guy

I used the angle aluminum to make brackets for rear-wheel dropouts. I also used it for brackets for the two ends of my underseat steering rod.

You could use where you need to join members at right angles.

sunnyboy44

I have had a busy time at school and finishing a model plane of mine- updates will come when work gets done
-Sunny