deus ex machina?

last night i undertook a bicycle tinkering project that i had been awaiting for some time. i wanted to change the gear ratio on my fixed-gear commuting bicycle, and convert from a 3/32" to a 1/8" drive train at the same time. going to a taller gear was a practical desire, as i had been spinning out with my existing 45:20 combo (although getting that loaded steel beast up hills was certainly no problem). going to the larger chain was more a vanity thing, thinking it somehow truly meet and proper (as it were) for a singlespeed. after finally procuring a 44-tooth 144 mm bcd front chainring, to go with the 17-tooth track cog i already had in my parts box (one of at least a half dozen clementine boxes, actually) i set out to make the switch.

the work went easily enough, given that the existing cog had been secured with blue loctite since last october. but the results were disappointing for a couple of reasons. first, the chainring had roundness issues. i got the rear wheel snug at what seemed like a good chain tension, only to have it sag and tighten as i turned the cranks, in perfect synchronicity with their rotation. i adjusted the location of the ring, which helped a little, but not completely. perhaps in the light of the day i can get that a little better.

second problem is chainline, and the fact that the 1/8" chain is far less forgiving than the 3/32". the cog is out as far as it can go already - too far, in fact, to put the lockring on. this is because the loctite from before got into the spacers and i couldn't get them off. a shorter bottom bracket spindle would help - i am using a found-it-laying-around shimano spindle that is 113 mm - i need to get hold of something meant for a triple, more like 108 or 109 mm. the wheel could also be dished less, to gain a couple of millimeters, which i will need once i get a spacer off to make room for the lockring.

the third problem was related to the lack of lockring and the glue not being dry when i took it for a test spin to get the cog on good and tight. just a little backpressure was enough to totally spin the cog off. ass! my bike went from completely rideable to completely unrideable with just an hour's effort. this is what most people would call a failure. at least i wasn't planning on riding it to work today anyway. but damn. i was hoping god would appear, hanging off the end of my chainwhip perhaps, but it was not to be, not last night anyway.

time to get to work. tomorrow we go to the velodrome! haha! and i can fuck around with the bike later...