Building a Bamboo Bike

[Kalle Knast]

Hi,
I'm trying to build a bamboo bike. I roughly follow Brano Meres' strategy: http://www.bmeres.com/bambooframe.htm. First build a jig that holds the components in the correct positions, and then join the bamboo rods with carbon composite joints. Now, I'm about to finish the jig, and figure it's time to learn a little bit about bamboo.

I'm looking for bamboo rods that first, can be bought in USA, second, have a 4-6 cm (1 1/2 - 2 1/2 inch) diameter, third does not break even after several years, and fourth do not crack (or cracks as little as possible).
Or any other properties that are desirable from bamboo bike tubing.

Which bamboo should I chose? And, how do I tell a good bamboo rod from a bad (provided they are the same species)?

All advice are appreciated.

Thanks,
kalle knast

[langsen]

I hope I am not hijacking your thread, but I am also building a bamboo bike and it can be difficult to find information. I collected my bamboo from a local grove and then cured it in my oven. I don't believe the species of bamboo will significantly affect the strength of a properly designed bicycle frame. If the bike is stiff enough to ride, it is strong enough. As for the cracks, I think they will inevitably occur some time down the road. I plan to wrap the cracked section of the culm with epoxied sisal fiber.

The joints are the crucial bit. I'm curious about your frame jig -- I was having difficulty coming up with a jig that could handle the variations in bamboo diameter and straightness while still maintaining correct alignment. How have you built your jig? How are you mitering your joints? Are you going to vacuum bag the carbon fibre?

I just found some very helpful photos that show Craig Calfee building a bamboo bike using Gorilla Glue, polyester resin, and sisal fibers. I think it's called the "Bamboo Bike Project".

Please describe your project in more detail, I'd enjoy to hear about it.

[Kalle Knast]

Hi,
You are certainly not hijacking my thread. Happy to discuss the project.
Excuse me for the delayed reply, but the jig was not quite ready (and still is not), so in order to be able to show how I want it to work I needed to build a little more on it. I just finished, but unfortunately I ran out of supplies and could not complete the particular part. Anyhow, it can still illustrate my intention. So...
As Brano Meres, I want the jig to fix the metal parts (seat tube, bottom bracket, rear dropouts ...) in their exact positions. Once they are in place, I think the bamboo tubes can be held in place by gluing them to the metal parts. See http://www.bmeres.com/carbonframe1.htm for an example with carbon. I will probably try to use carbon fiber for the joints, but I also have seen Calfee's bikes with joints of natural fiber and epoxy. They seem great, but I think making joints of such fibers requires more skill since they only have strength in one direction, unlike like woven carbon cloth.

About the cracks, Brano told me that his frame still (after 3 years) do not show any traces of cracks. But, unfortunately, he does not know which kind of bamboo he used, only that it was treated against insects.

http://www.princeton.edu/~turesson/jig_seatPost_2
http://www.princeton.edu/~turesson/jig_seatPost_3
http://www.princeton.edu/~turesson/jig_seatPost_4

Thanks,
Kalle Knast

[langsen]

The jig looks good! I don't have a jig yet. I've been trying to decide between something like the 8020 frame jig:

http://www.instructables.com/id/EAGXSQSF18DW8ZH/?ALLSTEPS

or the jig described in Talbot's framebuilding book, or even something ultra-simple, like the PVC elbows Craig Calfee is using as a jig here:

http://duck-rabbit.ldeo.columbia.edu/bamboo/Photos.html

I'm using the free version of bikecad for most of the frame design:

http://www.xcontario.com/bikeCAD.html

and the tubemiter software for all the mitering templates, it's a great combination. I just need to finish up the design and start building.

Are you building a mountain bike or a road bike?

More importantly, did you find a source for the bamboo?

[Kalle Knast]

Hi,

I will try to build a mountain bike.

The 8020 jig looks great, but I think it will be a bit unpractical for bamboo bikes. Since you will wrap the joints in some epoxi-drenched fiber, you need good accessibility around the joints. The 8020 jig seems to only provide good accessibility in front of the frame, but not behind, between the frame and the jig.

The ultra-simple Calfee jig seems to require a lot of skill and experience in order to get the parts properly aligned. He might use some special trick to control the alignment of the parts, but from the pictures I have not been able to figure out what it is.

My jig is probably pretty bad it you want to use it with a cad drawing, because it does not have any good reference points for measuring angles. For example, the seat tube holder (see the figure) has many more degrees of freedom than the seat tube holder on the 8020 jig. I think this is something that will make it very hard to get the alignment right, if you use the type of jig I'm building and want to start from a drawing of a frame.

To avoid this problem, I will use my old frame (which I like (not the specialized in the picture)) to align the jig. Place it in the jig, lock the jig in position, then take out the frame again without disturbing the alignment of the jig (sounds tricky, huh?), and finally, place the new parts in the aligned jig. Or something like that.

I have not yet decided how to chose bamboo. Any advice are welcome.

The finished seat tube holder:
http://www.princeton.edu/~turesson/jig_seatPost_3_sml


Thanks,
Kalle Knast

[drwelby]

Hi, I designed that 8020 jig and I just found this discussion looking for backlinks to the page.

One thing you should know is that frame jigs are only for tacking. You don't want to weld a frame that is so rigidly constrained because the heat of welding or brazing causes metal expansion. Since the metal has nowhere to expand easily to, it instead will cause weird alignment and buckling issues.

Generally, you tack the frame to hold alignment, then take it out and finish it in a repair stand.

With bamboo you don't have the heat problem, but you can do the same thing. Tack the bamboo with epoxy, then when it cures take it out and do your wrapping.

In my jig if you want more room on the backside, just space the fixture points away from the frame using pieces of 8020. It's easy, it's like an Erector Set for big kids.

Marc

[Mark Meckes]

Hi, This is a very interesting and inspiring discussion!
While y'all are working on the frame, here's a prototype for a bamboo wheel.

http://www.bamboocraft.net/gallery/data/3019/medium/1030907-779.JPG (http://www.bamboocraft.net/gallery/showphoto.php?photo=316)

This wheel, minus hub, is one single culmtinuous piece of bamboo, cut from a single culm.
There are no connecting joints except where the last spoke ends and the first spoke begins.
Because it is a continuous piece, and the way in which the cut culm is opened and formed into a wheel, and the way in which all of the spokes (strips) are positioned in vertical alignment, this structure is very strong. Also very hard to explain. :confused:

Anyway, I am jesting on the notion of adding a rim and tire to it and turning it into a bike. :p
This wheel was one of these accidental discoveries while playing with bamboo.
In this case folly preceded form and function.

Regarding bamboo for your project ...
Here's a generic listing of Bamboo pole suppliers in the US (http://www.bamboocraft.net/poles_raw_materials.html)

Also I would suggest that you start a New Thread at the Bamboo Sources Wanted (http://www.bamboocraft.net/forums/forumdisplay.php?f=103) Forum
... and provide details of the specifications needed.

In your situation(s) I'm presuming that you're not after large quantities of bamboo but rather the best quality for the project and of the dimensions that you need.
I'm sure there's got to be someone around who would love to know that some of their bamboo became part of a bike.

Apart from the diameter and lengths that you need, here's some things to consider in the course of selecting bamboo for your project.

- Straightness - varies with species/selection process
- Culm Roundness - varies with species/selection process
- Taper of length/consistency in diameter - varies with species and portion of culm selected
- Culm wall thickness - varies with species and portion of culm
- Weight - varies with species, culm portion and age at harvest
- Node prominence - varies with species
- Internode distance - varies with species and portion of culm
- Surface color - varies with species or manually applied treatment
- Resistance to splitting - varies with species, age of culm, and post harvest treatments

Mark

[langsen]

Is there any species of bamboo that would be too weak? I'm under the impression that, for the most part, bamboo is pretty strong. What's the weakest (lowest MOE, lowest tensile strength) species that can grow to > 2" diameter?

I'll take a guess -- tell me if I'm wrong -- if I find a 2.5" culm of any species of bamboo it should be strong enough for a bike? (Given suitable curing, joining methods, frame design, etc).

I like the bamboo wheel! It looks awesome. How do you make it? Like you said, I wouldn't use it on a bike, but it is incredible.

Here is a sample joint I made to practice using the tube mitering software:

http://farm2.static.flickr.com/1273/1085165710_73e1969437.jpg

Like drwelby suggests, I plan to use the jig to tack the frame together with epoxy, then wrap the joints with sisal/epoxy after the frame is out of the jig. I'm considering vacuum bagging the joints, but I'm not sure if it's necessary. Either way, the whole thing should be pretty messy.

These guys were on this forum a couple months ago:

http://daedaluscycles.com/bicycles/home

Looks like they've made some cool bikes so far.

[Mark Meckes]

Hi langsen,
Regarding structural properties of different bamboo species, unfortunately I have found little info that truly emcompasses every aspect about the hundreds of possible craft and construction species, and the info I've seen has been of fairly general analysis with little details of growing conditions etc.
Compound this with the fact that a very small number of species materials are available commercially in the US, most imported, though there are hundreds of species growing in horticultural environments.
Other species in different parts of the world are available on a mostly local/regional basis.

When harvesting bamboo, one thing I notice is the great variability of culm quality in a grove. This is most evident in a wild grove in which there is a great deal of competition for growing space among the mass of culms, living and dead, and difference between that which is growing at the outside periphery or interior of the grove.

Some things that affect a culms quality are ...

Location of planting
Climate certainly affects the culm quality, additionally, events such as ice storms and snow load on culms can cause minute cracks which can show up later in the harvested material.
One method to detect minute surface fissures of dried bamboo is to wet the culm surface, and if a minute crack exists it will show as a fine darkened line.

Local growing conditions
Soil type, nutrients, water availability, sun exposure, spacing etc all affect a culms quality.
As examples of differences ...
Culms growing on drier hillsides with more sun exposure and less growth nutrients may be smaller in diameter/height but can be tougher/stronger.

Culms growing in more shade with more moisture/nutrients may grow larger/taller and are good for splitting.
Similar conditions apply to basket makers selecting tree wood species for basketry.

Age of culm at harvest
This obviously affects culm quality as does managing/selective spacing of the culms in a grove, because overcrowded culms are individually able to grow fewer leaf branches, which can also result in a shortened life span of a culm and less accumulation of the substances which bind their fibers together in their after life.

One indication of age/culm quality of bamboo can be seen in their color and weight and flex. If you have an opportunity to sort through a large amount of bamboo you might notice these differences.
Green and dried have different tell-tale signs which varies with species.
This is where experience comes into play, as after a while one gets a feel for these things.

Post harvest treatments
This certainly affects culm quality, especially due to the nature of bamboo. Degradation of the bond between the fibers is not evident till after the drying process has ceased.

Then of course there are differences between species or portions of species which affects their strength.

- Wall thickness (species types and culm portion)
- Woodiness/density (species type and age of culm)
- Internode spacing (species type/portion of culm - Closer nodes + stiffer boo)
- Culm surface texture (species with more porous surfaces are more affected by exposure to weather/degradation without a protective coating)

In the case of a bamboo bike frame, using relatively short pieces, I would think that the critical component will be how the connections are made.

Regarding making of the bamboo wheel ... I was sure I wrote about this but can't find it. I'll put something together about this soon.

Cheers,
Mark

[sfeland]

I am planning on building a recumbent bicycle out of bamboo but I need to learn more and will need to build my frame jig as well. I enjoyed reading your posts and wish you the best building your bikes!

[langsen]

I look forward to seeing the bamboo recumbent!

A couple people have recently posted homemade bamboo bikes to velospace. Here is one from Princeton, NJ:

http://velospace.org/node/7419

The jig looks very simple.

Here is one from Asheville, NC, also with a simple jig:

http://velospace.org/node/8221

[M0rtii]

Ok, so I recently returned from Italy where despite being an avid mountain biker, I gained a whole new appreciation for riding. I also stumbled on Brano's instructable and have been inspired to begin designing a carbon/bamboo bike as well. (It's nice to know others are trying.) I have absolutely no experience in design and engineering, only some carpentry, so I'm gonna do this crash course style. From what I've read about the different types of bamboo available near College Station (i.e. in Austin and Houston), and from what others here have said, it looks like my best options for a strong (horrible word) species would be iron, guadua, calcutta, or black. And as someone mentioned, it really shouldn't make that big of a difference, but my biggest concern is that something like iron bamboo, since its solid, might weigh too much. I've never handled much bamboo, aside from a cane pole, so I don't know if it would still be relatively light, despite a solid core.

Any thoughts from those who have more experience. Better yet, if you had to just pick a species off the bat that sounded good, what would you go with?

I'm also thinking of making a run to pick up samples and do stress tests for myself.

[drumstickguy]

Incidentally, I have a friend who did a research project where he filled the tube of a bike with syrofoam, and it GREATLY increased the strength of the frame, w/o making it much heavier.

[bruce rutter]

I'm also working on a lwb. touring recumbent.with 29er wheels. I'm currently building a steel prototype first to get my frame geometry down. I've had a hard time getting any reliable information on what epoxy would work best on the joints any advice would be apreciateiated. also has anyone done any work on epoxy coating the inside of the tubing to lock the fibres. or would this ruin the vibration dampening characteristics of the bamboo. is there any data on tube diameter to stiffnes ratio for a given wall thickness for different species. and lastly is there relative advanteges of sissal vs, yute, vs hemp ? I'm greatful for any efforts to dilute my relative ignorance

[chiapasfix]

these are the bikes ive made so far. ive used dendrocalamus strictus ("iron bamboo")and phylostachys babusoidea (madake). they are both doing great, and are real strong. i used both hemp and sisal fiber. so far, i see no real difference between the different materials, except that d. strictus is heavier, but also stiffer. i am going to make the next one out of phylostashys aurea.
http://img158.imageshack.us/img158/5870/dscf5989sg8.jpg
http://img247.imageshack.us/img247/4665/cargocruisersq0.jpg

[CaroleMeckes]

Wow chiapasfix,
Those are beautiful bamboo bikes!
Carole

[bruce rutter]

Thanks for the info. Any Idea of the weight on these frames?

[bruce rutter]

What adhesive do you use on frame and what do you use on the wrappings? do you use any kind of anti fungal or epoxy on the inside of your tubes?

[attyphleger]

where did you get the second plan?

[rrooster]

To Chipasfix: For the iron bamboo, have you found any cracks?

[markatmizzou]

Hello all, I am new to the Bamboo forum but I am an avid cyclist. In looking at bamboo bikes online and the ones folks are working on here I have noticed that no one is using metal lugs which surprises me, it would seem like that would make the bike look cleaner and besides, lugs are cool. Any thoughts?

[stevelau1911]

Are they lighter than regular bikes made from aluminum?

[markatmizzou]

almost undoubtedly, Aluminum will be lighter than Bamboo. Even if the bamboo tubing is lighter the joints would not be, which is why I was asking about lugging frames with traditional metal lugs. Anyone know anything about that?

[Todd The Carver]

I am a fan of bamboo and recumbent bikes, and attended UBI's frame building class. Several years ago I found reference to the "Bamboocyclette", a commercial bamboo bike built somewhere in Asia. I have not looked for it lately.
As to the question of lugs, my concern would be that the edge of the lug might create a stress point in the bamboo. I suppose if your epoxy was 100 % rigid, and adhesive, it might work. I would actually make the lugs very short, like 1-2 inches. This would theoretically reduce the amount of leverage, and stress. I don't have the mathematical knowledge to calculate stresses, nor have figured out how to use autocad. If anyone can cast a calculating eye on these theories, have at!
I knew a guy once who made a bike-towed 'Camper trailer'. He could stretch out in it, and could tow it wherever he went.
Can't wait to see how this works out. I'd love to do something similar.

[langsen]

I've considered metal lugs for quite a while now, and come to the conclusion that metal lugs would be too difficult to use in this situation, mostly due to variations in the diameter and shape of each individual bamboo culm (some are oval, some are mostly round, etc.). I suppose you could select bamboo for a particular frame, and then cast lugs specifically for each joint of that particular frame, but otherwise I don't see how you could find lugs that would fit well enough.

Also, since this is essentially a bonded frame, the lugs need to be much deeper than those you would use on a brazed steel frame. The extra depth provides greater surface area for the epoxy to bond the materials, which is necessary because epoxy is much weaker than silver or brass brazing material. It would need to cover something like 2" - 4" of the bamboo (depending on diameter) to create a strong joint. Notice the depth of the lug sockets on a steel lugged carbon frame.

As for the weight issue, I believe the metal lug would likely be heavier than an epoxy/fiber joint. Consider that the bamboo used for the main triangle is probably between 1.5" and 2.5" in diameter, and imagine the weight of a steel lug of appropriate diameter and length.

It would certainly look a lot better than the epoxy/fiber joint. I'll give it that much. So, how about using carbon fiber lugs, custom formed for each joint?

[philwebb333]

Hello folks, I'm new to this thread. I'm getting excited about the idea of building a bamboo bike. I live in northern Thailand, where there is bamboo everywhere and used for everything, except for bikes. Thank you for the info shared. I especially like the bamboo spokes... sweet!

[vishaldpatel]

Can someone comment on the weight of a bamboo bike? Where does it fall in relation to other materials - aluminium, chromoly, carbon etc..? What about structural rigidity / overall practicality?

[craftscn]

It is so amazing to see your Perfect bamboo bike, it is an unbelieveable bamboo craft. It takes a lot of hard work

[bicyclelover]

Hey there,

Just wanted to share with all you fellow bamboo bicycle buds, that if you are sourcing your bamboo, I can offer you vietnamese tam vong. Its not even hollow, yet fairly light. Just email me at bicyclesandmorebicycles@yahoo.com

Justin

[andrewsarena]

Really! amazing job you people did a great thing..... never seen a bamboo bike.

[bikebuilder]

Hey,

Some of the projects you guys have been working on are absolutely beautiful.

I might tackle one of these myself, but I need to solve a few things before trying it.

1. I can't figure out for the life of me how in the world the seat tube works. Is there a metal insert in there? Did you ream out the bamboo before putting the insert in there? Or did you just ream out the bamboo and use it without an insert? Also, how did you ream out the bamboo?

2. Does the resin stick to the metal bits? How did you guys do that? Just majorly rough it up?


Thanks,

bikebuilder

[Juneau Bamboo]

Hello all- here in Juneau Alaska we have put together a group to while away the shortening winter nights. We expect to pool together resources to build some bamboo bikes!
So far we have done all the research I'm sure you all have, found the instructables, etc. We have a bucket of epoxy resin and tools, etc.
Bamboo Hardwoods (http://www.bamboohardwoods.com/) is supplying us with some Tam Vong bamboo- I highly recommend them as their service has been great and they practice sustainable harvesting.
I have a question for any and all who know about this- what is your opinion on using Tam Vong? It is a structural type used throughout SE Asia. It is almost solid (little to no voids) and we were thinking of drilling it out to size. Kind of like milling really.
I will keep you all informed as we make progress but so far we are excited!
Check us out! (http://www.juneaubamboobike.blogspot.com/)

[bikeninja]

Hey ya'll great posts thus far, very helpful. I am currently in the process of building my first bamboo frame, so far it's been alot of fun. I am using Black bamboo for the top tube, seat tube and Tonkin for the dropouts. Does anyone know how to achieve the asthetic quality of joint that Calfee is producing? His are smooth and do not really show the hemp fibers. Any ideas?

[bikeninja]

I am also curious of the diameters of the bamboo you guys are using for the top tube and seat tube?

[danimal]

It appears that the joints are way over-wrapped and then sanded to shape. I build surfboards and so have a fair bit of experience with composites and epoxy resin. I would pre-tack one end of a length of raw hemp fiber w/ two minute epoxy (that can be obtained at any home improvement store) at the joint. Then wet out the rest of the fiber making sure to get full saturation. I would use resin with a forty-five minute pot life. Once you start your wrap, that initial tack should enable you to pull a good tight wrap which is crucial right up next to the frame members to minimize voids. You are going to want as much fiber in there as possible. Then just build up that joint, give it at least twenty-four hours to cure and sand away, being careful not to remove too much material. One more thing about epoxy resin for anybody wanting to do this, is that it MUST be thoroughly mixed. The resin will not cure on its own without the hardener. You could end up with gooey pockets throughout the joint. A good rule of thumb is three minutes of continual, vigorous mixing with a wisk. I hope this was helpful. Good luck!

[bikelife]

Hey ya'll great posts thus far, very helpful. I am currently in the process of building my first bamboo frame, so far it's been alot of fun. I am using Black bamboo for the top tube, seat tube and Tonkin for the dropouts. Does anyone know how to achieve the asthetic quality of joint that Calfee is producing? His are smooth and do not really show the hemp fibers. Any ideas?

Calfee are sanded and sanded till shape is formed.
you could to a outside mold to make some shape to it.
of just wrap in electrical tape and that would get it close.

[mmann1123]

Hey everyone I have found the large majority of 'how to' sites lacking in specificity. I am putting together a blog with a lot more detail and experiments together come check it out at http://bamboobike.wordpress.com/.

There are a lot of pictures and good details on how to choose materials, how to miter better, even how to make a hemp fiber head tube etc. Hope it is helpful.