Mountain Biking - Fron Derailuer size?

Right now I am buying a new front derailuer for my Trek 4300. I thank the Deore LX will do fine, but I am not sure what size to get. I have the options below:

http://www.titansfan098.com/uploader/derhelp.JPG

How do I decide which size to get? Any better than the others?

Thanks in advance!

the top pull means the cable comes down to the derailer from the top. Bottom pull means the cable comes up to the derailer from the bottom. Then the size, 1 1/8, 1 1/4, 1 3/8, is the size of the toob the derailer is clamped to. Just get a pair of calipers and measure it.

What's wrong with the one that is on it? There is not much difference between front deraillieurs, if it is not worn out or broken, replacement is kind of stupid if you ask me.

What's wrong with the one that is on it? There is not much difference between front deraillieurs, if it is not worn out or broken, replacement is kind of stupid if you ask me.


I will agree with this, My 10 year old Explosif is XT throughout, and I am still running the original front mech. Mind you I am on the 3rd rear mech now. My bianchi is younger and front mech is Acera. Once again on 2nd rear mech but original Front.

The only front mechs I have ever known to wear out are the real cheapies, and even they worked fine right up until they got so much play in them that they had to be changed.

Thanks for the input!

The reason I am purchasing a new front derailuer is because the metal cage that shifts the chain is bent, not fixable by adjusting the clamp that goes on the tube. Also, it is a thick 8 speed derailuer on a 9 speed bike. Not a big deal, but I may as well get a 9 speed one when I am buying a new one.

And one last question: What's the difference between a top pull and a bottom pull? Any performance difference?

Thanks again!

-Garrett

Thanks for the input!


And one last question: What's the difference between a top pull and a bottom pull? Any performance difference?

Thanks again!

-Garrett

No difference,in performance, but it all depends on what your bike is set up for. If the cable to the mech. comes from above, then you have top pull, if the cable comes from below you have bottom pull.

Incidentally. Deore front mechs are one size with shims for differrent diameter tubes, and I believe they are set up for top and bottom pull on the same mech.

Get this and don't worry about it: SHIMANO XT M760 FRONT DERAILLEUR. It's a snap to setup, too, with a multi-clamp band design that works for all three seat tube diameters, and a dual pull design that allows it to be used with either top or bottom cable routing.