Saturday, September 09, 2006

Bike Progress

Yes, we have a drive train! I was very busy this weekend and made some great progress. I installed standoffs for the upper guide roller, and both lower guide pulleys. I also tacked a stand pipe on the drive bracket to hold the front derailleur. I put a few old chains together, and tested the setup to make sure it would work. I'm not totally happy with my decision to use plastic idler pulleys in the lower run to inhibit the bouncing of the chain. They are a little noisier than I thought they'd be, and give a hell of a vibration. I might ditch them later for the rubber skate wheels since they don't have any real tension on them. The gear in the top run works great.

I installed a mount for the rear brake, and made sure it would work as I planned. Then I disassembled it again, and started cleaning up my amateurish welding job. There are a couple places that need to be ground off and rewelded, and a couple places where I probably could have done better if I had just closed my eyes. I think the hardest part of mig welding so far is being able to see what I'm doing - the gun hides so much. Anyway, I have much more to do, before assembling it the next time. I also still need to build a seat, which will be a challenge due to so many variables and arbitrary things like wide butt, skinny butt, lumbar support, shoulder support, tilt, back length, adjustability...

I started to add cable nips to allow naked cables for the long straight runs, but after tacking one on, decided to bag that idea and just have the flexible housings run the full length of the cable. It really wasn't worth the extra work for......why do they do that anyway? I mean how much weight do you really save? I can't see how it reduces friction in the housing, since the friction occurs at the bends, and you haven't eliminated any bends.

I'm sure that when I'm done with this project, I'll look back on it and have to conclude that I know nothing about bicycles, welding and design. But maybe that's not the real goal here. It's a chance to learn to weld, and to play around with bikes. It's also a chance to build something myself, and to use my tools which otherwise collect dust in the garage. But more than that, it's something positive in a world that sometimes seems pretty dismal. My bike is always there waiting for me to come out and play, and it will always be as good as I want it to be.

Jack

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