Rear Mech - need some advice PLEASE
 

Turns our the the rear Mech I bought is different to the one I currently have on my other bike - shud hv checked before I bought.

On my first bike I have an XT which is the the one that when the cable tension is increased the chain is moved inwards towards the larger cogs. The new XT one I bought is reverse to that, i.e increasing cable tension moves chain to the outside, smaller cogs.

So now I know there are different types of XT derailleur - is one better for shifting that the other or is simply preference ?

If it is preference I will stick with the one I am used to, therefore, what is XT type called that moves the chain inwards when tension is increased.

Also, how do I know if I need a long or short cage for the new bike I am putting together ?

THANKS !

Its called 'Rapid Rise'.

Long Cage - wider range of gears
Short Cage - shorter range of gears
I can't remember how to know exactly what is recommeneded, i think there was a 'forumla' or something i read. I"ll try and find it for you!

:)

Here you may find shiny_car's post of help to you :).

[QUOTE=Riles]
is one better for shifting that the other or is simply preference ?
QUOTE]

I've been running both for almost a year now, with approximately equal usage, and can honestly say that I don't think that there's really any difference in shifting performance, so for me it would just be preference. There is some kind of shimano press release type thing that I've seen that says which one is better for what, but I can't remember what it said.

Capacities of deraillers is on the shimano website to compare with your cassette to decide long/short cage.

i prefer a med. cage rapid rise rear mech. over others... it just seemsmore natural shifting and the sort

I was under the impression that long cage deraillers were for bikes with 8 or 9 speed cassettes that have a 3 gear chainring and short cage deraillers are for bikes that either have a narrower cassette or have a 2 gear chainring. alot of street bikes also use short cage I guess because the lower gear on the cassette isnt as big so the chain doesnt need to move as much. I could be wrong but that was my understanding on lc or sc rule of thumb. as far as towards or away I dont think it makes a difference except for the type of shifter you have. one will move it one way and the other the other way.

the longer cage is just to pick up slack.. so the smaller the granny upfront is the more likely it is you need a long cage.

i use a med. cage because i dont use my granny gear up front, i usually only use the big ring or middle...

nevertheless, longercage is for slack pick up on smaller front rings