Crazy Idea: bamboo swift folder
 

I've been lusting after the James' Swift folder for quite a while, but I wanted something with a cushier ride. Also, I'm really cheap and I like bamboo (it's really nice to work with).

I'm thinking of building one out of old bike parts and bamboo based on the swift folder design.
I'll probably be using salvaged BMX dropouts, a titanium bottom bracket shell, an old seat-tube, and an old headtube. I'd appreciate any tips...particularly suggestions on the pivot joint.

I think that I've figured out almost everything except for the fork (although it'd be nice to see a swift in person).

Anyways, my big question is the fork: should I go carbon (bmx) or suspension (Meks)?

I want the folder to be simple, efficient, and fun. However, I also have arthritis (very early stage) and want to reduce road vibrations as much as possible.

-matt

Bamboo is cool, like it alot. I guess you`we seen what is going on with bamboo in the "Framebuilders forum"?

I wouldn't put carbon anything on a folder. The bike needs to be able to withstand more damage than normal from bouncing around in a suitcase, closet, or trunk. Carbon isn't really good for that.

I'd probably use metal seatstays to make the folding mechanism a little easier. How are you going to get a flat bamboo main tube?

alex

FWIW.... I hope you already have some experience building frames, as well as working with bamboo. If you do not construct the bike properly, you could easily wind up kissing asphalt whilst riding 15mph or faster, hardly a pleasant experience.

Along similar lines, I'd be concerned about a bamboo bike without a downtube. Aluminum tubing is quite strong for its weight, and can be shaped and butted for additional strength; the top tube of a Swift is fairly large and robust. I don't know if you can find / grow a bamboo pole that will match the same strength as the Swift's top tube.

Also, let's face it... If you need to reduce road vibrations, an unsuspended 20" wheeled bike simply is not the way to go, and even changing frame material is not going to make a huge difference. If anything, cushy tires like Big Apples, and possibly a carbon stem, carbon handlebar, gel padding and good bar tape might do the trick. But unless you have a critical need, I'd look into either a suspended 20" folder or, better yet, something with bigger wheels.

1. I like bamboo because I can get it (SF Japantown), it's clean to work with (no need for torches in my Apt), and it has a very high strength (it'll bend before it breaks).

2. While I'm not expert at bamboo bike building. I consulted a guy at TAPS plastics who advises some custom framebuilders that use bamboo:

I really don't like risking injury, so I've over-engineered everything. The bamboo's air dried (not flame dried). It'll be reinforced with epoxy sealer. The inside will be reinforced with polyurethane foam. The outside will be reinforced with hemp lugs (ala Bmeres).

I also don't plan to do any messenger-esque stuff (racing cars, going against traffic,etc). If I build the bike, I'll be testing it gingerly at first (residential street, curbs) before riding around town.

4. The toptube will be two tubes of bamboo strapped together in parallel. They're 29 mm in diameter with 5 mm walls.

5. I will be using a metal seat-tube, metal seat stays, a titanium BBshell, metal dropouts. Anything contacting metal will be metal.

6. I've been following the bamboo thread and Bmere's thread for a while. Over spring break, I gathered material from around sf. I'm building a bamboo fixed gear cyclocross bike based on the Waterford X-33.

The swift folder actually is a logical candidate for this manufacturing method. It only has one hinge, and an elegantly simple geometry.


Thanks for the suggestion Baccialupe. I'm already planning on using the Big Apples (heard good stuff on them). I'm not sure on the carbon stem (where do I find one long enough?).

awetmore, I'm curious about the need for metal seat-stays. I was just going to use metal for the top 3 cm (the actual overlap point to the tube), and joint it to bamboo. I'll stop considering carbon (I'll need to see how much a swift fork costs).

I'm still curious about the fork, since I've heard good stuff on the Mauna Kea thread about the MEKs fork on his DT.

Sounds like you are good to go. :) I will be watching your progress with great interest.

I would go with a normal fork and Big Apples to start with. You can always put on a suspension fork later, but my guess would be it won't need it.

The seat post is an integral part of the frame's strength, so make sure it is good enough for the job.

Actually, Jur, after reading your posts on the DownTube mini SA review, I wonder if I'm just being a nut.
While I have a feeling that I could do it, and do it well, I wonder if it's worth doing anymore.

Between managing patients, practicing root canals, and starting a goofy little "side business" to raise money for my sister's graduation present (establishing a "Matt Lau brand" of cookingware for med students who can't cook, and making jewelry).

(On the side note, if anyone's interested in commissioning custom jewelry, let me know. I'm thinking of inlaying swarovski crystals or opal carbachon's on my sister's future green ipod nano. I also do stock stuff like earings, pendants, etc, but I'm super busy with school right now.)

Yan's bike sounds ridiculously good. I'm 5'8, 165 lb (lost too much muscle), and I like to explore in conjunction with public transit (a small fold is great). I'm extremely demanding on my equipment (thus, I made my own PW Martin 000-12-fret guitar). If I can add drops and fenders, it'd be ideal.

Honestly, the crazy idea was just to meet a desire. The Swift folder frame is about $550, just out of my price range. But SA hubs in conjunction with everything else is really sweet. I may still build the bamboo folder in the future though...after reforming the US medical system, making millions of dollars, and opening my own business (it'll take a couple decades, wiht luck).

ps. Jur, I forgot to say that you're awesome. Aside from being in great shape, you managed to do some crazy touring on a small folder.
Hat's off mate!

Maybe a more "Strida like" folder is easyer to make out of bamboo. Not sure about the wheels though, might want to go for something more like a normal fork to hold the whels in place (not one-sided).

Well thanks! *blushes* You're in a different league altogether! I get fatigued just reading all you do.

I have had my fair share of widely diverse hobbies... won't bore you with a complete list, some of the highlights were homebrewing (from scratch), recorder playing, pressure lantern collecting/restoring, woodworking, choc cake recipe designing, programming the ill-fated eBookMan, and as many I don't remember right now. But I didn't do them all at once.

But building a bamboo bike for its own sake sounds like just the thing to try out. I'd try it if I could lay my hands on some bamboo, but I don't hold high hopes... :(

I don't know about a different league. For one thing, I'm less than half your age. For another, I'm not as in shape as you are (for now). Almost all of the hobbies above are direct offshoots of my dental school training, so it's not like I needed to devote tons of time learning them.

Seriously, school forces one to be either creative and slightly crazy, or a machine. You can guess what category I fall under.

The hobby side business thing is two parts experiment, one part joke, and also a way to make friends. Also, it lets me buy more raw parts to make cool stuff to give to people.

-matt

hmm, so no bamboo folder?
ive built 3 bamboo frames so far. one of them broke due to it being eaten by fungus before i built the bike, and I did not notice.
the other two are doing fine, even the bamboo cargo bike which has carried as much as 200kg no problem (made of iron bamboo dendrachalamus stictus)
ive thought of a bamboo folder, but have serious doubts as to how to do it, as the other frames are all based upon the double triangle design, which keeps lateral torque from cracking the bamboo.
so maybe having a real long main triangle?
then you get into hinges.....
hmm a real challenge indeed!

I saw some beautiful road bike frames built out of bamboo somewhere on the internet once upon a time. They were really works of art and were on sale at a very high prices. Carefully selected, it is a very strong tubular material and extremely light too, I think. As I recall, I think they had metal forks and dropouts.

Sorry, no bamboo folder. (Although I might change my mind in the future). Since I have a limited time to see patients, I figure that I'll focus on the rootcanals and crowns now, and think of bamboo folders later. My original vision was the Swift in bamboo: 1. it's a simply hinge that doesn't require propietary parts, and can be built big without hampering effectiveness. 2. The frame design is very strong--while a unitube probably shouldn't be done with bamboo, it'd be not too hard to have a simple truss. 3. The bike itself is a joy to ride, very efficient and stiff. It wouldn't be too hard to adapt whatever parts you want to add, provided that it can be on the original Swift. After riding on the Xootr swift for the past several months, I've really fallen in love with the bike. It's top speed is a bit limitted compared to some fancy road bikes and it's not good for offroading, but it's ideal for street riding. It's also very fun and solidly built. My main issue was building the Jigs. I'm currently too anal, and too lazy to build it (I'd rather graduate first).

Well that's a disappointment!!

I thought we were going to see some marvellous developments here.

bamboo is fantastic material.

http://craphound.com/images/bambooframe.jpg

http://www.bmeres.com/images/bamboo3.jpg

http://www.bmeres.com/images/bamboobike.jpg

http://www.calfeedesign.com/images/bamboo.jpg