i have a shimano deore mega 9 crankset. can i use an xt 8 speed rear mech or does it have to be a 9 speed?

Answer 1

You probably need to repost and clarify a few things- do you mean crankset (which is the front three gears) or cassette (which is the gearing on the rear wheel, usually 7 - 9 speeds)? Also, by rear mech, do you mean derailleur, or rear cassette?

I can tell you this - when Shimano moved from 8 to 9 speeds they changed the chain, so a 9 speed crankset and an 8 speed cassette might be problematic.

If you are only worried about your rear derailleur, then you should not have much of a problem - just set your adjustment screws correctly and go.

Answer 2

No. You need to match the cassette with the shifters on gear count with indexed shifters. If you have friction shifters, the size of the cassette doesn't matter. EDIT: What is a mech? Do you mean hub? Freehub? A 9 speed cassette should fit on a 8 speed freehub. A 8 speed cassette should therefore work with a 9 speed free hub.

Answer 3

It'll work perfectly, it's the amount of cable pulled by the shifter that governs how many gears. I'm using and old 8 speed Acera rear mech on my 9 speed Merlin at the moment after a stick ripped off the LX one! And to be honest, the shifts are crisper than my new Mongoose LX dual controls!!

Answer 4

I did this on a bike some years ago. I used a 9 speed compatible front derailleur along with that 9 speed compatible crankset. However, the rear derailleur, sprocket, shifter, and chain were 8 speed only. In my case, I had no problems.

Answer 5

Its better if you have a 9 speed

Answer 6

Yeah it's fine as long as you use an 8 speed chain. I take it your shifters are 8 speed too?

Answer 7

No Idea what the helll are you talking about