Rear mech to cassette difference

Ollieda

I've got a 7 speed cassette and trying to buy a new rear mech. Just wondering if theres any problem putting a 8,9 or 10 speed mech on and adjusting the screws so it won't got further that the lowest and highest gear? Also if I do this and then get a 10 speed shifter, is there any problem having the rear mech set to only cover seven gears as the limiter screw should stop it going any further if I've failed to count to seven and am trying to shift further than I should right?

I know the simple answer would be to get a 7 speed rear mech but I'm looking at upgrading my wheels and cassette around September so just trying to future proof my shifters / rear mech.

topdude

An 8, 9, 10 speed mech will work as the shifting is determined by the shifter not the mech.
You can't change to a 10 speed shifter with a 7 speed cassette as the shifter will move the mech in smaller steps so the chain will not line up with the sprockets, so you will need to fit a 10 speed cassette to use a 10 speed shifter.
Read this http://www.sheldonbrown.com/k7.html for more info on gearing.

Ollieda

right then, I guess i'll just stick with my current rear mech till i'm ready to upgrade my wheels and casette.

Thanks for the info