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Silly question RE: MTB rear derailleur compatibility(6 posts)

Silly question RE: MTB rear derailleur compatibilityfloatch
Nov 11, 2002 9:18 AM
Hi all! I'm in the process of building my own cross bike from parts I'm ordering (and backordering, and backordering, etc). I'm planning on running 9 speed Ultegra STI levers, and I'm wondering about the shifting performance differences between an Ultegra rear derailleur, and maybe XTR or XT. I have a 12-27 cassette, which I know will work with an Ultegra RD, but I'm thinking shifting might be a little more reliable with an XT or XTR? Are the upper cages the same?
I know some of you guys are running a mix of MTB and road parts, so please let me know what I can get away with.
I'm relatively sure STI will work with pretty much any shimano parts, but I just want to make sure. There's nothing worse than skipping gears on a nasty uphill, right? Thanks, all!
re: Silly question RE: MTB rear derailleur compatibilityclimbo
Nov 11, 2002 11:37 AM
Ultegra should be fine, I see mostly road ders. over MTN on the East CX scene. Basically most people run whatever they have, if they had a spare XTR they'd run it. I use Campy so can't really coment on shifting performance but the only way to get perfect shifting is to go single speed. You should be fine.
re: Silly question RE: MTB rear derailleur compatibilityatpjunkie
Nov 11, 2002 1:20 PM
have run both XT and XTR on Ultegra STI's. No problem, cages are a little longer and may be prone to snagging but it hasn't happened yet (I don't think I've snared a long cage rear derailleur) on my MTB either. This is usually the arguememnt against long cage derailleurs. If you plan on thrashing your bike or riding in bad elements you may want to go with bar ends as Shimano STI's are prone to clogging and dying and aren't repairable. It can get quite costly. I ran STI's that died an awful death way before their time. Have switched to bar cons and am quite happy. Cheaper, fixable, great in mud and friction mode on the front allows you to feather the front der.
re: Silly question RE: MTB rear derailleur compatibilitylaffeaux
Nov 11, 2002 1:32 PM
The rear cassette also comes into play. Since you're running a 12-27 you can run either a road or MTB deraileur. However if you went with an larger MTB cassette 11-32 or 11-34 you should probably use the longer caged MTB deraileur (especailly if you have a triple on the bike). Different set-ups require different parts. The advice to go with whatever you have laying around is the best.
re: Silly question RE: MTB rear derailleur compatibilityatpjunkie
Nov 11, 2002 2:31 PM
Shimano Road der. will work up to 27, after that it's MTB. Campy's will go to a 29. The cross Nazi's will tell you if ya can't push it in a 39-27 you should be running. I'm 230+ and run a 36-30 on one bike.
re: Silly question RE: MTB rear derailleur compatibilityjrm
Nov 11, 2002 4:46 PM
Im using an LX derailler with a 12-27 cassette and it works well.