I have a 1990 Trek 1420. I recently replaced the speed downtube shifters with 8 speed sti levers. I found a balance to where everything works pretty well, but not flawlessly. I figured that was just the comprimise I would make for the convienience of STI levers.
However, I got to thinking. Can I fit an 8speed HG cassette in place of my 7speed HG cassette? Is the overall size of the cassette the same or am I not going to have enough room for an 8 speed? My frame has 130mm rear spacing. I am assuiming that the worst case scenario would involve redishing my wheel to create some room?