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  1. #1
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    Medium Cage on Mountain Bike

    What are your opinions on running a medium cage rear derailleur on a standard mountain bike drive train (standard == something with approx 45T chain wrap)?

  2. #2
    Redheaded Stepchild samburger's Avatar
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    Works for me for the time being, running a 3x9 speed 11/42 setup.
    just a n00b with an ego

  3. #3
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    Quote Originally Posted by samburger View Post
    Works for me for the time being, running a 3x9 speed 11/42 setup.
    Which gears are problem gears for you, and do you ever forget and accidently shift into them?

  4. #4
    Redheaded Stepchild samburger's Avatar
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    What exactly do you mean by "problem gears"? If you mean gears that just don't shift smoothly, I don't have any. X9 derailleurs are wonderful If you mean gears that cause the chain to rub the derailleur, that's a result of poor choices in shifting, & can be corrected by never shifting to a high (small) gear in the rear while in the granny gear up front, & vice versa.
    just a n00b with an ego

  5. #5
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    Hmmm...no, I mean a medium cage derailleur has approximately 33T chain wrap capacity (slightly higher for SRAM I think--maybe 37T). And a full range mountain bike gear set is usually around 45T (for example, a 22/32/44 up front and an 11/34 rear would give you (44-22)+(34-11)=45T chain wrap). Therefore there would be some gears that would simply not work with a medium cage derailleur. Depending on your chain length, if it was long, then you'd eventually lose the ability to take up slack in small/small chainring/cog combos, or if your chain was too short, you'd jam up the drive train trying to shift into large/large combos.
    Last edited by IntoTheWild; 10-15-11 at 06:52 PM.

  6. #6
    Redheaded Stepchild samburger's Avatar
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    Hmm, not sure about that one. It's entirely possible that I'm recalling memories incorrectly & I have a long cage, but I could've sworn I got a medium. I got my derailleurs from fleabay, any way you know of to measure & check to see whether it's medium or long? You've got me curious now..
    just a n00b with an ego

  7. #7
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    Not sure of measurements, but here's a picture:

    rderailleurs.jpg

    Also, for Shimano derailleurs, the model number will have GS designation on the end for medium cage and a SGS for long cage.

  8. #8
    Ho-Jahm Hocam's Avatar
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    How often are you in the big ring? I think you'll be fine for the entire middle ring (32-22)+(34-11)=33

    Or you could go 2x9.
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  9. #9
    Redheaded Stepchild samburger's Avatar
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    Dug up the box the derailleur came in, 'tis a long cage after all
    just a n00b with an ego

  10. #10
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    Quote Originally Posted by Hocam View Post
    How often are you in the big ring? I think you'll be fine for the entire middle ring (32-22)+(34-11)=33

    Or you could go 2x9.
    Yeah, I use the middle ring mostly, although I use the small ring for the most part on one particular trail. Due to that latter fact, I would want to shorten the chain so all my gears in the small ring are useable. Of course this makes it dangerous shifting into the big ring if I'm not mindful of what I'm doing. I guess it's a question of how much I trust myself. I rarely use the big ring, though.

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