Monday, January 08, 2007

Ch-Ch-Ch-Chainges



This weekend I replaced the idler gear in the tension side of the chain with a skate sheel. Actually, it's a 3.8" wheel from a Razor scooter. I chucked it up in the grinder as suggested here, and sharpened an old screw driver to cut the groove. It worked like a charm, but the melting rubber smell was disguting even with the garage open. I also did away with the return side idlers, and replaced them with a tube. During comparison tests in the repair stand, I noticed quite a bit of drag coming from them all, and I never did like the vibration. The new chain controls seem to make a huge difference in both issues.

Jack

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Wednesday, January 03, 2007

What can I say?

Well, the pictures pretty much say it all. I felt brave Wednesday, and with a break in the rain, I decided it was time. It went pretty much as I had planned. My kids took the pictures.

I started off in the garage, going only a few feet on the first try, while staying close to the wall to grab on if I needed to. On the second shove-off I went for it, pedalling down the driveway, and turning slowly left to circle the cul de sac once before pulling back into the garage. It takes a conscious effort to turn, since I had to start by leaning the bike into the turn, which is done by steering the bike out from underneath me. It will take some getting used to, and takes a little more forethought than an upright bike, but it feels comfortable to control. Given time it will be, well, as natural as riding a bike.

The gearing felt fine, had it in low gear, but shifted up for the third try. The smaller pulley in the tension side of the chain is a little noisy. The chain hopped off of the smaller idler pulleys in the return side, but I knew this would happen. I know I need to make some keepers to go around the chain to keep it on the pulleys. That was a known problem. Also known was the fact that the grip shifter is terribly mismatched to the rear shifter. One click results in a shift of three gears. I'll be putting the thumb shifter back on at final assembly.

The first attempt at stopping was odd. The seat bottom is too long, so it's difficult to drop both feet to the ground at the same time. The trick is to drop one foot, keeping the other on the pedal, and lean enough to be stable. The first time I stopped, I just grabbed the bike stand to prop myself. The second time I almost fell over. The third time I did it right, but awkwardly.

Other things I think I might change are building a new seat (of course - same back curves and slope, shorter bottom, more downward curve at the front edge, and sliding it forward about an inch), possibly replace the small idlers with rubber skate wheels (quieter), moving the real idler pulley inward about an inch to better line up the chain, and maybe push the handlebars forward an inch or two. The handlebars are fine right where they are for riding, but they make mounting/dismounting difficult because of the way they overhang the butt. I find myself having to tip the bike off to the side while I straddle it, then lifting my leg over the bar and pulling the bike back up again. Wierd. I did some measuring with the crank assembled, and decided I have room to squeeze in the third chainring up front. I'll have to do that before paint, as I'll need to cut off the stub of tubing the front shifter is mounted on after I get a final location for it.

Both of my kids came out to watch me ride it, and took turns taking pictures - the best of which are posted above. Thankfully I didn't crash or they would have taken a very clear picture of that. And thankfully, no neighbors were out. Now to make some changes, ride it again, then take it all apart.

Jack

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