Originally Posted by Squeazel

Thanks!

I thought it would be easier with the Shimano 3-speed cogs, too. I tried 2 different ones, and 18 and a 21 tooth, and they both skipped under load. I decided that my chain was incompatible somehow- I only had a 7-speed chain, so I broke apart a 7-speed cassette and modded those cogs. The beauty is that the original shifting ramps on the cogs are lined up since they used to be adjacent on the original cassette, so the shifting is absolutely flawless.