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 ...

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