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.