Best bamboo bike build anywhere !! I love how you kept the joints nice and slim so that the frame flows smoothly and doesn’t look like Fred Flintsone made it
Hi breathestrong, Was it flexing at the lugs, or in the tubes ? The direction the carbon runs in is very important, it has a very high tensile strength but poor compression, so you need to get the length of the fibres across the joints as close to 90 degrees as possible to prevent hinging, and then consider the direction of any forces that will be transmitted through each joint and wrap accordingly. Bottom bracket is probably the worst as it takes force from almost every angle, I used combinations of 3k twill and 12k tow to get the structural strength there. If it was weak tubes, you could cheat a bit here. Take an old 700c 20 - 25 inner tube and cut it 8” from the valve, tie a knot in each end and wrap with saturated twill cloth (enough to expand to the I/d of the tube. Knock the nodes out of the tube and clean the inside with glass paper on a stick. pass the wrapped tube down the bamboo pole and inflate the inner tube, once cured deflate and remove the inner tube this will give you a composite component that has carbon fibre strength with bamboo looks.
Lez C I used jute, which I now know was a mistake so I think it was mostly the lugs. Also the tubes were possibly too small diameter so my next frame will most likely use carbon and larger diameter tubes
Effin h, mate. Mind blown!
Best bamboo bike build anywhere !! I love how you kept the joints nice and slim so that the frame flows smoothly and doesn’t look like Fred Flintsone made it
awesome video, cant wait to start building mine!
Great build!
My first build was a flexy disaster, now I know what I lacked...patience 👍
Hi breathestrong,
Was it flexing at the lugs, or in the tubes ?
The direction the carbon runs in is very important, it has a very high tensile strength but poor compression, so you need to get the length of the fibres across the joints as close to 90 degrees as possible to prevent hinging, and then consider the direction of any forces that will be transmitted through each joint and wrap accordingly.
Bottom bracket is probably the worst as it takes force from almost every angle, I used combinations of 3k twill and 12k tow to get the structural strength there.
If it was weak tubes, you could cheat a bit here.
Take an old 700c 20 - 25 inner tube and cut it 8” from the valve, tie a knot in each end and wrap with saturated twill cloth (enough to expand to the I/d of the tube.
Knock the nodes out of the tube and clean the inside with glass paper on a stick. pass the wrapped tube down the bamboo pole and inflate the inner tube, once cured deflate and remove the inner tube this will give you a composite component that has carbon fibre strength with bamboo looks.
Lez C I used jute, which I now know was a mistake so I think it was mostly the lugs. Also the tubes were possibly too small diameter so my next frame will most likely use carbon and larger diameter tubes
Lez C also great tip about the internal reinforcing! Tnx 👍
so how is the bike holding on these days?
Also interested in that.