Saturday, May 15, 2010

Bike Project

I've been meaning to document some of my ideas and designs concerning bicycle transportation, and now seems like a good time.

I've commuted by bicycle since I was eleven years old, when I passed my Cycling Proficiency Test and received a permit to bike to secondary school. Until around 2000 I rode classic 12-speed sports bikes with drop handlebars, but then I started to experiment.

After my frame broke for the second time, I thought I'd try a mountain bike, but with road tires and drops. It worked ok. (See picture.)

For bringing things to and from work I attached some steel boxes, intended for hanging file folders. They locked, and were totally waterproof. They were a bit noisy though, going over bumps in the road, especially when carrying metal objects. I wondered if full suspension might be a good idea.

At about the same time I started to experiment with rain ponchos. The idea I had was for one that was as small and tight as possible (no big flapping thing). More like a tent than than poncho, hence the provisional name "bike tent". It attached to the frame of the bike, by means of a bar that projected forward from the headset. The hem of the poncho was stiffened by a rather elaborate contraption consisting of a chain threaded through short pieces of plastic tubing. (When the chain was put under tension, the hem became stiff.) It worked well, although I still needed to wear waterproof boots and gaiters.

I thought about putting panniers at the front, the idea being that they would block some of the rain hitting my shins, as well as improving the bike handling. Here's a picture of the styrofoam plug I made, intending to make the part from fibre glass. The plug was shaved down to the point where I could ride with hitting my knees on it!

Unfortunately the bike itself was stolen at this point. Time for a new bike, and chance to experiment with full suspension.

Here are the front panniers, and I stuck a bit of a fairing on the front of them, a bit like a motorbike. I thought it might look nice, as well as perhaps making it more aerodynamic. You'll also see the aluminium tubes added to strengthen the rear carrier.

It looked better with a lid, and a paint job.

Now, at about this time my wife and I had our first child, and I wanted to bring him with me. Throwing him in the cargo box made a good picture, but wasn't practical for the roads.

But products are available for this sort of thing, fortunately. One doesn't have to invent everything!

So the bike was developing nicely into a pretty useful machine for getting to work, carrying groceries, children, etc. But for a while I'd thought about adding an electric motor to the bike, to see how that would be.

One of the ideas driving these experiments is that cycling has a lot to offer developed countries, as well as developing ones, in terms of reduced congestion, improved health and fitness, reduced cost, less pollution, etc. Of course cycling is rare in Canada, due to numerous barriers, some of which can be addressed by changes to the bike itself. The main barriers are:

1. It's perceived as dangerous.
2. It's too strenuous (especially going uphill).
3. The range is too limited.
4. You get wet, or otherwise have to put on a full-body rain suit.
5. You can't bring enough stuff with you.

#1 is of course a misperception. The best measure of the total risk of an activity is its effect on life expectancy, and cycling increases life expectancy (as well as general health). We just have to get the word out.

#2 is addressed by adding an electric motor. The motor's output is roughly that of a fit human, about 1/2 horsepower, which makes a big difference.

#3 is also addressed by the motor. It allows higher speeds, at the same or lower level of effort by the rider, so that longer commutes become feasible.

#4 is addressed by the bike tent (see above and below). It's quicker and easier to put on than a rain jacket, pants and overmitts, and it's much better ventillated, so you don't get sweaty. (Especially with a motor as well.) You can ride to work in your work clothes, even in heavy rain, and arrive perfectly dry.

#5 is addressed by stay-on-the-bike, waterproof storage panniers, as well as by trailers (see below).

As you see, I chose a mid-drive system, where the motor is mounted to the frame and drives the crankset. The engineer in me liked the idea of the motor driving the wheel through multiple gear ratios, so that the motor is always close to its peak power and efficiency. (This is the Cyclone motor, by the way.) This first setup had 8 speeds, from the cassette on the back wheel. I figured I didn't need any low gears, with the extra 360 Watts on board.

However, once you have some extra power, it's tempting to increase the loading. A second child appeared, and sometimes they want to bring friends along! My flat bed trailer, intended for cargo, sprouted a back rest for children. (I also continued to experiment with the "bike tent" concept, now adding what look like umbrella tines.)

The next post should take us up to the present ...


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  2. Good stuff, thanks for sharing your ideas.