Brian wrote "I have found a use for the adjustability of rear dropouts. I tried to
get one of my old Colnagos to shift with a large inner cog on a 7sp
freewheel. It would not shift until I let the screws way out, suddenly
it worked fine. Still does. Sometimes it's all about the shifting."
When doing this I have found that if the derailleur will shift from the fifth cog to the seventh, but not from the sixth cog to the seventh that the chain is too tight. Adding a chain link at this point will help and should have you shifting in all combinations. This can be a lot of chain, though, and with a short cage derailleur you may get some rattling back there.
Tom Sanders
Lansing, Mi