8 speeds on a 9-speed cassette?
I have a well-used Trek 520 that is in need of a drivetrain overhaul. The older RSX 7-speed STI shifters are showing their wear (the right one slips on downshifts occasionally) so I'd like to replace them with bar-ends. I've noticed that 9-speed bar-ends are much easier to find than older 7-speeds. Since I have a 7-speed freehub on the bike now that's in good shape (just the cassette needs replacement), I'd like to keep it. I just read the following on Sheldon Brown's site for a description on a 7-speed freehub for sale:
"You can use a 7-speed cassette, or, if you want more gears, you can install 8 sprockets of a 9-speed cassette, and use 9-speed chain and shifters to get 8-speed shifting without exceeding the 126 mm spacing."
Has anyone ever done this? This would solve several problems for me: it would allow me to use the current wheel and dropout spacing and replace the worn shifters with new bar-ends. Since I plan on replacing the cassette anyway, the extra expenses would be for shifters and brake levers, which I'd need to get once my current STI's complete their disintegration. Once the wheel wears out I could replace it with a 9-speed and be on my way. If not, I run the risk of spending the money for a new 7-speed drivetrain which would be rendered obsolete if my shifters give up.
So, have any forum members ever attempted the 8-speeds-from-a-9-speed-on-a-7-speed-hub trick mentioned above?