Semester Bicycles- Hextube bamboo composite frames made in the rural South

Commuter, Concept, Utility / Cargo Bike 9 407

Semester-bicycle-sideI was born in Alabama, and spent the first 18 years of my life there, so I was very happy to hear about a bike related project that is focused on creating jobs and better lives for people in one of the rural communities in the Black Belt region of the state. In the town of Greensboro (not far from the area where the Rural Studio program at Auburn University’s School of Architecture is working to improve the lives of poor, rural residents through design), a collaborative design group called MakeLab has partnered with HERObikeFuture PartnersPublic-Library, and industrial designer Lance Rake to develop a bike that can be made locally from the bamboo that is abundant in the region.

Semester-hextube-sketchesTake one glance at the bike, and you can see that it is different from the bamboo frames that seem to be everywhere these days. The main triangle is comprised of engineered composite bamboo “Hextubes,” which you can see in the sketch above, and the photo below. The Semester Bicycle Kickstarter page explains:

 “Each tube is actually a structural stressed skin composite: a bamboo core is skinned on the inside with carbon fiber and covered on the outside with a durable glass/epoxy lamination. The bamboo fibers run parallel along the length of the tube, while the carbon fiber and FRP skins are laid at 45° giving torsional rigidity and protecting the bamboo. The resulting Hextube is incredibly strong and lightweight.”

Semester-bicycle-hex-tubesThe fact that these are engineered tubes means that they are always consistent in size, shape, and performance, so they can reliably mate with the steel headtube and rear triangle that make up the rest of the frame. That makes this design more manufacturing friendly than the majority of bamboo bikes, which need to be individually custom fitted and joined due to variations in tube diameter and wall thickness. Since the goal of the Semester Bicycle projects is not just to produce bamboo bicycles, but to create jobs for the people of Greensboro, that consistent manufacturability is quite important.

Semester-bicycle-teamThe video at the top of the Semester Bicycle Kickstarter page does a great job of explaining the project. For more information, there is also a good post today on the Core77 blog written by the designer, Lance Rake. As an Alabama native and a fan of local small scale manufacturing, this is definitely a project that I am personally backing. They have 13 days left to meet their $40,000 funding goal on Kickstarter, so I encourage you to stop by the page too, and help them create a better community in the town of Greensboro if you can.

See additional images below (courtesy of Lance Rake and the MakeLab team) including more of the development sketches, and a few prototype frame designs.

Semester-bicycle-sketches

Semester-bicycle-sketches-2

image

Test model made from hextubes and lugs fashioned from a salvaged steel “cadaver” frame

Semester-bike-prototype

Design experiment using bamboo hextubes

Semester-bike-prototype-2

Early version of the hextube bike with external lugs and smaller section tubes


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9 Comments

  1. Impossibly Stupid August 15, 2013 at 4:50 pm -  Reply

    Holy crap, this is actually a well-executed concept with reasonable prices! That $1300 full build sure looks sweet. Who knew bamboo fenders would be so pretty?

  2. Matt August 16, 2013 at 7:19 am -  Reply

    But why bamboo? Surely you could just make it out of carbon? It’d be a whole lot lighter.

    Seems perverse to make claims about bamboo being sustainable and then use carbon fibre, epoxy, powder coat and other polluting, unsustainable products to make it. I’ve got some vegan shoes that are made from dead cows but the laces are hemp…

    Still, can’t knock these guys for providing work for communities

    • art August 21, 2013 at 2:01 pm -  Reply

      Because making the tube out of all carbon requires a bunch of layers, which gets expensive fast. This composite looks like a really good balance between the cost of bamboo and the consistency of an engineered material.

      The only thing that concerns me is that they say the hex tubes are incredibly strong, but don’t provide any mechanical or environmental test data. Delamination is going to be a serious issue with moisture and temperature variation. The fact that they say the use of dissimilar materials “dampens” road vibrations doesn’t lend confidence that they have any real data.

  3. MJ August 17, 2013 at 10:43 am -  Reply

    I like the idea. In terms of materials use, I’m not sure a bamboo bike actually out performs a cycle made from re-purposed or recycled steel or aluminum. Unless of course there is a compelling argument about carbon sequestering in the growth and harvesting of the bamboo.

    Thoughts?

    • Paolo September 14, 2013 at 10:00 am -  Reply

      carbon is already difficult to recycle, is a mix of different components, the idea to mix also with bamboo is not so good, i can see here not a eco bike but a not reusable mold for the carbon.
      I don’t like any kind of wood bike, the longevity of a bike some time is more than 10 years, the industrial production of a metal frame take a lot of energy, but at the end you have an object (that without accident) could life forever or be recycled 100%.The value of this project probably is in the production process more than in the product. the same concept could be more useful for furniture design.

  4. Rick October 4, 2014 at 9:09 pm -  Reply

    Well, the Hex Tubes sure look interesting.

    One could use wood instead of bamboo. I could envision using a mix of different types: walnut, cherry, oak, etc for a fine furniture look or even using them in fine furniture for legs or shelf supports.

    Inlay “decals” would be cool too.

    How difficult is it to remove the inner tube after the epoxy sets up? Does the epoxy stick to the rubber or does it peal away easily. Or do you have to use a release agent or another non-porous layer such as Mylar?

    Thanks,
    rick

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