Bicycle Mechanics - Can I put a long cage on my med cage derailluer?

I'm having some issues getting the right chain length with my three in front and my nine in back cog setup. I have an RD-M950 xtr rear mech that I'm using right now but I think that to get the full range of cogs I will need to use a longer cage rear mech. I also have an lx mech with a longer cage but I am wondering if I can switch the cages and still use the xtr.

Anybody ever done this?

I doubt it. If you had a XT and an LX I would say it is possible but I am sure XTR is completely different setup. You need to find a place that has a listing of small parts like that and has an interchangability chart.

I doubt it. If you had a XT and an LX I would say it is possible but I am sure XTR is completely different setup.

Why are you sure, tried it?

I'm having some issues getting the right chain length with my three in front and my nine in back cog setup. I have an RD-M950 xtr rear mech that I'm using right now but I think that to get the full range of cogs I will need to use a longer cage rear mech. I also have an lx mech with a longer cage but I am wondering if I can switch the cages and still use the xtr.

What's the issue you're having? If it's too much chain when in the small chainring and smallest cogs, be advised that you really shouldn't be using those combos. ;)

You are talking Shimano, they are not so good at selling the spare parts..

I did such before but it was a Campag Euclid MTB, RD,
and they dropped out of the MTB sector over 20 years back.
and I did so back closer to the production dates..


Just go shopping for a new one..
You would do better just getting a whole Long Cage rear Derailleur.

You are talking Shimano, they are not so good at selling the spare parts..
Campy is rapidly following in their footsteps.


Just go shopping for a new one..You would do better just getting a whole Long Cage rear Derailleur.
+1 Or just use the LX you already have. I expect the difference in shift quality between it and the XTR will be minimal to nonexistant.

A lightly used long cage derailleur would be cheaper than parts, if parts were available, which they aren't.

All new (2012/2013) XTR derailleurs are the new MTB 10 speed type, which will not work with your 9 speed shifters and cassette.

What are you max/min cogs and chainrings? Shimano publishes the 'capacity' ( (max cog - min cog) + (max chainring - min chainring) ) that their derailleurs can handle, and if your setup is less than the published capacity, it will work... if your setup is more, however, it either won't work or you will have to select chain length to allow shifting into the bag/big combo and avoid small/small.

OK, here's an exploded view of your existing rear derailleur. (In German.)
http://webandy.hekko.pl/shimano/TM/RD-M950_1996.gif

If I knew which LX derailleur you were talking about, I could make a guess, but it's pretty unlikely. Shimano tends to make the cage interface different between the various derailleur grades, much less different years.

I agree with HillRider: put on the entire LX derailleur. It's a couple grams heavier, but it'll work fine.

http://webandy.hekko.pl/shimano/jpg/Shimano_Anleitung_RD-M950-96.jpg

If you have a long cage that fits, it's worth a try. Putting long cages on e.g. Campy Nuovo Record derailleurs is a well established practice:

http://www.os2.dhs.org/~john/nr-rally.jpg

Ok, so it sounds like switching the cage is out...plus after looking at it closer the parts that I have are incompatible and I definitely am not wanting to order any parts (I am already waaaay over budget on this bike and I am afraid my wife's patience might run short).

I suppose I could just throw the LX on there but I have heard that some people will use a shorter cage and just avoid certain gear combos. I figured that I could set up the chain length so that the big-big works so that I dont blow up my drivetrain on accident and just never use the small-small.

This way I can have the quicker shift and better tension of the shorter cage xtr (plus I wont feel guilty knowing that its sitting in a box).

Is this crazy, naive, immature? All I know is what I read on the net so I open to correction.

Thank you

Ok, so it sounds like switching the cage is out...plus after looking at it closer the parts that I have are incompatible and I definitely am not wanting to order any parts (I am already waaaay over budget on this bike and I am afraid my wife's patience might run short).
A very common problem.:)


I suppose I could just throw the LX on there but I have heard that some people will use a shorter cage and just avoid certain gear combos. I figured that I could set up the chain length so that the big-big works so that I dont blow up my drivetrain on accident and just never use the small-small.This way I can have the quicker shift and better tension of the shorter cage xtr (plus I wont feel guilty knowing that its sitting in a box).
Yes, that works fine. If you assure big-big works for safety reasons, avoiding small-small is easy as it serves no purpose and, even if you accidentally shift into it, no damage is done.

As to the XTR offering "quicker shifting", maybe, maybe not and I doubt it would be noticable in real life but the satisfaction of using the better component is there.

Cool thanks!

Use a road cassette FTW.