[vitox]

Yes it does. A medium cage x.9 will only take up to a 32t on the cassette, while a long will do 34t. Brand doesn't really matter, but size does.

i think theres a problem here with the jargon

a longer cage will make the derailleur take up more slack, thats what you guys keep referring to.

the pulley and body design is what makes the derailleur be able to reach a larger sprocket, and in thise case that doesnt change between the long and med cage versions.

the number you are referring to is the max. difference between amount of teeth, that the derailleur can still take up slack in.
for instance if you have a 12-34 setup, and a 22-32-44 setup, then if you use the 34 cog and 44 ring, youd be using 78 teeth, and if you use the 12cog and 22ring you would be using 34 teeth, meaning your derailleur would need to take up 78-34 teeth of slack which is 44, outside of range. but since you never go smaller than 16t on the 22ring and never bigger than say 24 on the big ring, your maximum needed tension capability drops back to 28 which can be served by a mid cage derailleur, now factor in a chain growth on a dual suspension bike of the equivalent of 2 teeth and you have 30.

 

[urbaindk]

But listen to what you said...

You bent a cage.
Your spring broke
then something else broke that caused you to replace it
it lasted only months

In my mind that is unacceptable.

.

Let me clarify a little. The x.7 derailluer lasted for a total of about 1.5 years. After I bent it, it lasted another few of months (4 or 5) before something else broke during a race. It still shifted smoothly but it didn't pull tension on the chain. (somehow I managed not to drop the chain.) That's not too bad if you think about it. I was pretty pleased actually.

I've had two shimano (LX and XT) derailluers that I have bent. After I bent them back they catastrophically failed shortly after (roughly 1 month) sheared throught the aluminum casting. I've had a few others that just stopped working because something bent.

Personally I'd rather have something that bends a little and still sort of works than breaks and takes out a bunch of spokes as it goes.

That's my experience and I'll admit that my sample size is rather small so take it with a grain of salt.

I'm going on about 6 months now with the x.9 with no problems.