Query-

RE: 7 speed Sora, are shimano 7 speed cassettes spaced the same as standard (ie. you can buy new) 7 speed freewheels? I saw on Harris Cyclery the Sora 7 speed shifter and said compatible with both, but sheldon's cribsheet on spacing seems to suggest otherwise.

I'm curious because I've got a NOS bike I want to use for cyclocross that has a 6 speed freewheel drivetrain. I switch back and forth between the original wheels with the knobbies and modern cassette wheels with slicks and just use the bar-ends in friction for the modern wheels. It'd be cool if I could put a 7 speed freewheel on the original wheels and a 7 speed cassette on the new and have indexing for both. Plus I'm feeling I might want brifters if I race it.