i have a set of vento's that are 8 speed and i run a 9speed marchisio cassette on that, it works fine, they are imported by a company called RSI, same people who do all the Ambrosio bikes, rims etc.
the marchisio sprockets are basically problem solvers for people like us who refuse to stop using old stuff! i'm not saying it is definately possible but it's got to be worth a look. the sprockets work by having a carrier that fits the hub with a sprocket of the correct width for the system you want then fits on the carrier then a spacer the right width then another carrier, sprocket and spacer etc, the idea being that you can get carriers to fit different hubs and then space them for the system you use therefore being able to mix and match brands etc.
i think it will work because my wheels being 8speed but running 9 and my 9speed wheels run 10 aswel although this is all campag but i don't see why the shimano set up wouldn't work, with marchisio you would just use different spacers, the sprockets and carriers would be the same regardless of whether you run campag or shimano.
just find a dealer who has an acount with RSI or check this out. i used to deal with a guy there called martin when i was in the trade, always very helpful.
hope that helps, that is their website but i didn't see the cassettes i was talking about, give them a ring, i should add that the cassettes are about £100 but they last ages, mine is about 6 years old and still going strong, but i got one for a customer less than a year ago when i was still in the trade.
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