Drivetrain issues

Yesterday the chain on the road bike that was damaged in the wreck earlier this year came apart - one of the links just parted. I called home for a bail-out, then threw on a new chain and went to work.

As I expected, the cassette is worn and skipping with the new chain. This isn't particularly safe since I can't accelerate in traffic as well as I should be able to, so I have to do something about it before hitting the roads again.

My original plan was to convert to an 8 speed cassette. They're a LOT cheaper ($20 versus $60, and the chains are $8 versus $30) and 10 speeds is ridiculous overkill for me - there are gears in there where I can shift and I can't even tell the difference. With the indexed shifting, converting may involve having to do some fiddling with a cable pull adapter.

The Performance shop in A2 has both cassettes. I'm leaning towards making the move to 8 speed now rather than spending $60 on a cassette just to get my use out of a $25 chain. According to Sheldon Brown, the cog spacing on Shimano 10 speed is 3.95mm, on the 8 speed, 4.8. So it's likely I'll need a cable pull adapter. I'm toying with the idea of designing and 3D printing one. I'm sure I can pull off the pulley and use a standard bearing, but I'm not sure about the body of such an adapter. I MIGHT be able to pull one off fully 3D printed, by making a quite chunky body for it.

I can probably use the thing without the adapter in the short term, because I can feather the upshift.

Also, Sheldon suggests a couple of methods for slightly altering cable pull travel simply by re-routing the cable. Probably not enough to make up a whole millimeter per click though.

FOLLOW-UP: The 8 speed cassette I needed was $35, and Performance gave me a discount bringing the 10 speed one down to $52, so I just did that. I really don't have time (or in the winter, inclination) to do a lot of fiddling with an experimental drivetrain modification.

More bike fun

So I threw the new cassette on, and while I had it up on the stand I decided to try to figure out why it has been shifting funny lately. I found out it was only shifting over a part of its range and was very sluggish. While shifting through the range, the cable snapped.

It turned out the cable at the shifter had gotten badly frayed (surely as a result of the accident earlier this year) and stray strands were caught up in the mechanism. I eventually had to remove the shifter, which involved removing the bar tape and unstringing the brake cable from the bike. I had to partially disassemble the shifter to get all the bits of cable out of it. I have another cable ready to install, but with the weather looking like snow and ice tomorrow, I'll have to ride the winter bike anyway so there's no point in pushing to get it back together tonight. Besides, I need new bar tape anyway. I'll have to bring the bike inside to wrap the bar and get everything together anyway so I'm not worried about working outside in the cold either.