On a related note, just wondering: are all thread sizes on 1" pitch cogs the same? If one found a "skip-tooth" sprocket on eBay, would it fit any track bike or very old non-track bike, like post #1? Or are there various sizes (sheesh, French skip-tooth cogs ) I have a track bike, not finished, and I have a 6T and a 10T and suspect that, in use, do not want either.