13 February 2008

Why I think bamboo bikes fix the wrong problem

I've been seeing a lot of posts all over the interweb about wooden and bamboo bikes. Hey, that seems clever! Solves the world's problems! Right? I'm not so sure.

So, I agree it would be a great world if everyone who wanted a bike had one. And, I agree that bikes are better for developing nations (and all nations) than cars, since they provide mobility and portability with few/no recurring costs. They even have nice side effects, like physical fitness and zero pollution.

What I don't buy is whether a bamboo bike is any more accessible to the developing world than a steel bike. Here is why I think that.

My criticisms could apply to any bamboo bike, but for argument sake I'll pick one. Let's pick on Bamboo Bike Project, a joint venture between the Earth Institute at Columbia University and Calfee Design.

First of all, let me thank them for trying to do good in a world where so many don't do squat. My criticism is to encourage you to seek a more realistic design, not to discourage you.

My first observation is that the bike is not made entirely out of bamboo. All of the components are normal components (and note that componentry is generally more than 50% of the cost of a complete bike). Suspend your disbelief and assume we can get all of the sundry components to put a bike together; let's focus on the frame itself.

On the bamboo frame, the following pieces cannot be made out of bamboo:
  1. The head tube, since it must support the bearings in the headset,
  2. the bottom bracket shell, since it must support the bearings in the bottom bracket, and
  3. the dropouts, since they must support the wheel.
The photo gallery confirms all of these constraints. One could presumably make these pieces from scap, if one had a machine shop. But machine tools are expensive (a cheap milling machine costs $525, a cheap bike costs $50), so let's assume that we don't have one.

The only other solution is to scavenge them from metal bike frames, and then bonded to the bamboo frame. So where do those parts come from? In this case, those parts must be taken off of broken bike frames. In this case, we do accomplish reuse of a small fraction of trash frames.

However, I think we could accomplish more by attempting to repair those bike frames. The cheapest, most common bike frames are made of steel, and improvised welders are not too difficult. Also, Sheldon Brown gives instructions to repairing bent frames via cold setting.

What could be done to improve this design? I have no concrete points here, only general guidelines:
  1. Consider the context in which these will be built. Does it ever make sense to saw off 99% of a bike frame and replace it with bamboo?
  2. Focus on the consummables. Assume that bike frames are pretty easy, and instead figure out a cheap hack to replace burst tubes or tires, rusty chains, broken cables and worn brake shoes. In other words, follow the 80-20 rule for bike repair.
  3. Make the bike more useful. I see that they added a large rack on the rear for carrying cargo or additional passengers. That's golden! Pursue this further, design bike trailers, or figure out how to use a stationary bike as a motor to drive tools, feed generators, or purify water.


adrogersam said...

excellent. nice to hear criticisms from someone who knows what he's talking about. the bamboo bike does look cool, though... i like your last point, too, about putting existing bikes to more uses. i've seen some of this stuff first hand, and it's pretty awesome. i guess this shows again that while we have fossil fuels, we should be using them to make things like components, full bikes, etc. that we'll need once the oil's gone.

adrogersam said...

"etc." = solar panels for another example

m e l i g r o s a said...

I came across your blog recently and wanted to stop by and say hi.
This bamboo post is good. They are def. a new subject of conversation.