the time has come to replace the only remaining parts of my original bike making the build a complete one.

i am looking to replace the rear derailleur and cassette (8 speed) but im a bit confused as to which one to get.
long or short arm ? and why ?

im not a speed freak or a XC racer and prefer the more rugged type riding so would i benifit from the short arm ?

i was thinking about getting the XT but would any one suggest something different ?

nothing too pricey :)

It's all to do with how many gear combinations you have, but to keep it simple. If you're using three rings at the front you use a long mech amd if you have two rings at the front you use the shorter one.

Let me know if you want the complicated answer.

Basically, like Mike says, if you run a triple you want long cage.

You could get away with a short cage mech on a triple, but don't ever end up shifting into 'big-big' 'cos it'll end in tears

I know he's gonna ask for the complicated answer :-)

Subtract your smallest rear cog from your largest rear cog (eg:31t-11t=21), then subtract your smallest chainring from your largest chainring (eg:44t-24t=20)then add the two figures (eg:21+20=41) to give you the Total Capacity of 41t. A short cage XTR mech has a capacity of 33t and long cage 43t, so the long cage would be the right mech.

Spot the typo, should be (eg:32t-11t=21).

LOL

the simple one is fine mate :) (show off)

im running 2 up front 8 at the back so now that im armed with the relevent info i'll get the short arm.

thanks mike much appreciated.

No problem, someone would've asked.

i use a short cage mech on a triple chainring set up. and i have a pretty big big ring.

shorter cage gives quicker shifts, something i now know is definatly true since putting a roadie mech on my DH bike to replace my dead long cage LX.

like the man kato says, just don't shift into big - big.

but i'm sure you wouldn't do that anyway.... would you?

: )

not with a 2 ring/bbash guard set up :)

well i hope not !