I measured my 6 speed cassette and my 7 speed cassette and found out that the 7 speed is slightly wider, a couple of mm. No surprise. But since I dont have a 8 speed cassette then I cant measure it. So, my question is...

1. How wide is a 8 speed cassette?

2. How wide is a 9 speed cassette?

3. Since the 9 speed chain is quite alot narrower then the 6 speed chain, is it possible to get a old 6 speed front derailleur to work with a 9 speed chain if the shifters is friction and NOT index?

Cheers mate.