Sunday, May 23, 2010

New Bike Details

The basic features of my new bike were described in a previous post. In this post I'll show some close-up shots, and explain some of the technical details.

This first shot shows the dashboard. Right now it's just a mockup made from twinwall plastic. (I have plans for a nice piece of plywood.) The computer is the Cycle Analyst 2.0 from Their new large-screen model would work better here. The switches control two front lights.

The second shot shows the front panniers, with the child seat base between them, and the power switch for the motor and lights behind that. The child seat itself fits into one pannier, as you see.

Now we see the child seat installed, held in place by a single bolt into the base. The seat is by Wee Ride, but most of it has been chopped off. The foot rests were very small, for example, whereas the panniers allow even a six year old to ride comfortably, in something like a kneeling position.

The seat base also houses most of the electrical connections, including the Cycle Analyst shunt, as can be seen when the lid is flipped up.

Here you see the motor gearhead, mounted inside the frame triangle. The motor is available from Cyclone, with the gearhead attached. This is the 24V, 360W version, and weighs about 3kg altogether. The controller is inside the motor case.

The planetary gearhead provides about 9.5 : 1 speed reduction, and the chain provides another 2.3 or so (32/14), for a total of about 22 : 1. This is using the middle (32 tooth) chainring. I can also use the large (42 tooth) chainring, for a total of 29 : 1, so that the motor runs at higher rpm. This means less current, and more range, but less power and a higher-pitched sound from the gearbox.

The motor chain tension is adjusted simply by sliding the motor up and down the mounting.

Here the motor itself is visible on the right of the gearhead. Rather conveniently, all the places where water can get into the motor are between the mounting plates, basically inside the frame. This is a nice feature, since the motor itself isn't supposed to be used in the rain. In this installation, however, it's fully protected. (I recently found out that the duct tape above the motor is needed for this.)

You see how the wire entry point is protected.

The battery is the black thing at the top of the rear panniers. This one is a LiFePO4 made by Li Ping of Shanghai. The specs were said to be 24V 20Ah, but actually they measure a little better than this on the Cycle Analyst. Ping had to put the cells together in a different way in order for the battery to fit into the space. The price was also very reasonable, so (to this point, only 1300 km so far) I'm very pleased with it. (The weight is about 5kg.)

Finally we see, from above, the attempt to make the whole bike aerodynamic. The idea was to approximate the familiar "tear drop" shape of aircraft wings and so on. I can't say I've noticed much drag reduction though! I wonder if joining the front and rear panniers together, with side panels of some sort, would make much difference?

Sunday, May 16, 2010

Latest Bike

This is a continuation of my "Bike Project" post.

About two years ago my cheap Raleigh frame reached the end of its life, as the pivot bushing for the rear swing arm wore out, and couldn't be replaced.
So I searched for a new bike, looking for another full suspension frame as this is needed when carrying hard-shell panniers at high speeds on rough city streets. I also needed a frame that fitted my existing panniers, and with replaceable suspension bearings. The Norco Fluid met all these requirements. (See below.)

A new bike meant an opportunity to try new ideas. Some problems with the Raleigh were:

1. The low placement of the motor exposed it to water and mud.

2. The 8 speeds were fine for city commuting, but hauling a heavy trailer around the Gulf Islands required additional low gears.

3. The WeeRide front child seat mounted to an ugly, heavy steel bar clamped between the headset and seat post. It had to go.

These three problems were solved by a single new structure, formed by a pair of aluminium plates clamped around the frame by about ten small bolts. (See below.)

1. Holes were cut to mount the motor to one plate, in the middle of the frame triangle, a location that protects it from the elements. All the potential entry points for water are actually between the plates.
2. The motor was turned around, putting its drive sprocket on the left instead of the right (the rotation reversed). The left crank was replaced with a crankset, so that the motor chain could still drive the cranks as before. But the existing triple crankset on the right was left intact, so that the standard 27 gears remained.
3. At the top, these plates were joined by a sturdy piece of aluminium U-channel to form a base that the WeeRide attaches to by its usual bolt.

Detail of how the carrier struts attach to the frame.

The front panniers then re-attached easily to the aluminium plates, and the fairing went back onto the panniers. I made fibre glass rear panniers to match the front as well.

And that's basically it (for now). More technical details to follow ...

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 ...