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  1. #1
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    XT Shadow Plus RD selection help

    Hi--

    I need a new RD and am looking at the Shimano XT Shadow Plus.

    I need the normal, not rapid-rise kind. Tightening the cable shifts to a bigger cog.

    Amazon says it is "Top-Normal return spring optimized for RapidFire shifters". That is NOT what I want, right?

    Amazon.com: Shimano XT RD-M786-GS Shadow Direct Mount Rear Derailleur, Silver: Sports & Outdoors

    These guys list the same part# (RD-M786-GS) but say nothing about rapid-rise or not.
    Shimano Deore XT Shadow + Rear Derailleur (Mid Cage) - Brands Cycle and Fitness

    What's the deal? Will I have to replace my shifter to use this derailleur, or is there a normal model, or is it switchable somehow?

    TIA,

    Dennis

  2. #2
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    Did some more reading -- am I correct that the -SGS are high-normal, and the -GS are regular? If that's the case, Amazon has either the wrong description or part#.

  3. #3
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    The XT 786 Shadow+ rear derailleur is NOT rapid rise. The description on amazon is not very clear.

    You'll need dyna-sys 10 speed shifters for this derailleur. Also, depending on what chainring/cassette combo you're running you'll need to decide on long cage vs mid-cage. Long cage is for bigger gearing ranges, mid-cage for lesser range.

    Required Capacity = (big ring - small ring) + (big cog - small cog)

    Here is the long cage version (in black) of what you're looking for with a better description:

    Shimano XT RD-M786-SGS Shadow Direct Mount Rear Derailleur, Black : Amazon.com : Sports & Outdoors

  4. #4
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    SGS=long cage and GS is medium cage.

  5. #5
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    Thanks all for your help.

    Let me give a little more background on my situation. I caught a stick and bent the R derailleur hanger or so I thought. It was a pretty hard impact. It broke a spoke and bent two others, and I went down.

    I straightened the hanger, but the cage is now off at a crazy angle. I presume it is supposed to be parallel to the plane of the cogs? It appears to me that the whole mechanism is twisted, not just a bent cage.

    It shifts OK but is noisy where the chain enters the lower jockey in some combinations.

    Anyway, it is the derailleur I learned to ride on, it has 2100 miles on it, and I wouldn't mind upgrading it.

    As for long or medium cage, I have a homemade 2x10 conversion with 36/24 rings and 36/11 cogs, so I have a capacity of 37. The medium cage has a rated capacity of 35, and according to the sticky in this forum, it would be close enough. So I am leaning that way. Comments?

    Also, I am rethinking the Shadow Plus model and thinking of just getting an XT Shadow. That's what's on there now according to Trek.
    TrekBikes.com Bike Archive | 2012 Superfly AL Elite
    Chain slap or dropping the chain isn't much of an issue, and I am trying to make the thing lighter, not heavier. Plus there are fewer parts in the non-Plus I assume.

    Or go with a XTR Shadow non-plus while I'm at it? It isn't all that much more expensive than the XT Shadow Plus.

    Or I guess there would be nothing to risk if I put it in a vise and tried to bend it back. It does feel a little sloppy already though.

    Thanks again for your input.
    XT Shadow Plus RD selection help-bent-r-der-800.jpg

  6. #6
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    You can do with the medium cage. The shadow plus is really nice. I understand not wanting to make the bike heavier, but you're talking a 1/10 of a pound. If you really want to lose weight get new wheels or replace all your non-drivetrain parts or replace your entire drivetrain. I know that seems overkill, but a few grams here and there really doesn't make a noticeable difference. That Shadow+ is sweet. I'd go for it.

  7. #7
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    on my 3 ring setup i just switched to an xt shadow longcage from an xx medium and the shifting doesnt feel quite as exact with the long cage but otoh it moves to the big cog easier. New cable and housing feels so much better too

  8. #8
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    Shimano XT RD part numbers explained:

    Thanks for the input everyone.

    I was looking for a breakdown of available part#s. The Shimano web site is no help--it lists only one XT RD on the North American site. Europe and Australia list four, but the links don't go anywhere.

    So I called Shimano in Irvine CA and here is what I learned in case anyone else is interested:

    RD-781 Shadow
    RD-786 Shadow Plus
    All XT line is 10-speed, and the rapid-rise is no longer manufactured.

    As J.B. Weld already pointed out, GS is medium cage, SGS is long cage. There is an extra letter after the GS or SGS indicating Silver or Black.

    The RD-780 is a discontinued model replaced by the 781. "Minor changes" the guy said.

  9. #9
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    Ok, I ordered the 786 in medium cage. I rode a '13 Superfly SL which has this RD and it really shifted NICE. It had XT shifters and I have SLX however.

    Woodstock MT: ok on the extra weight. My son munged his cassette, so I gave him my SLX and got an XT. That will more than make up the difference, plus it's rotating weight sort of. A good wheelset is my next major purchase Lord willing.

    Thanks again everyone.

  10. #10
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    Got the new RD installed, and ya'll are right, it is a great RD. I'm not about to remove my chainstay protector, but it does eliminate probably 75% of the chain noise. I did find myself hitting the rough areas faster! It shifts great.

    And I never lost the chain. It wasn't but occasionally it did. I'm guessing that this setup will never drop it.

    The 37-tooth required capacity works fine with the medium-cage -- there is some to spare still.
    Last edited by DennisF; 05-25-2013 at 09:23 AM.

  11. #11
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    I'm looking to purchase the XT Shadow Plus. Going from SRAM X9/gripshift, so I'll need new shifters. Which Shimano shifters are compatible with the Shadow+?
    Would the Shimano XT M-770 shifters work?

  12. #12
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    Yes, any Shimano Dyna-sys (10 speed MTB) shifter will work. There was also some discussion in this thread about long cage vs medium cage.

  13. #13
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    I know it works with SLX and XT and XTR. I don't think there are any other models of 10-speed Shimano shifters.

    I upgraded from SLX to XT. Although some dispute this, I believe that the XTs shift easier (less force required). Someone said they have better bearings. And you can multi-shift in both directions.

    Also, the XTs have a 2x 3x switch that my old '12-model SLXs did not. I converted to 2x, so that was a nice plus.

    The XT is slightly lighter than the SLX (20 gram savings). Given the extra features, I'm just glad it isn't heavier.

  14. #14
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    I forgot to specify this is for 9 speed. The deraulleur is 10 spd, but you can adjust to 9 spd.
    The shifters I asked about are also 9 spd.

  15. #15
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    According to this guy (See #3), it can't be done.
    Dyna Sys 10 speed compatability with 9 speed (Shimano systems)

    I think you could just get a 10-speed cassette and 10-speed chain and be done with it. Not sure tho. I think I read here that a 9-speed crank will work with a 10 speed chain.

  16. #16
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    ^^ That guy is right. The cable pull is dramatically different on Shimano 9 and 10 speed. SRAM and Shimano 9 speed were the same, and Shimano diverged, perhaps to ensure that SRAM stuff could not be mingled with theirs. It also served to make it so that you have to have a complete 10 speed Shimano system, or not at all.

    A rear derailleur itself has no concept of indexing, so if the 9 and 10 speed shifters used the same cable pull it would work. BUT THEY DON'T. It won't work.

  17. #17
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    Thanks. Looks like I'll have to replace everything.

  18. #18
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    Quote Originally Posted by colinl View Post
    ...snip.. Sram and shimano 9 speed were the same..snip...
    no!
    Duct tape iz like teh Force. It has a Lite side and a Dark side and it holdz the Universe together.

  19. #19
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    Quote Originally Posted by mitzikatzi View Post
    no!
    Sorry, SRAM Attack. Not their normal line.

  20. #20
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    Quote Originally Posted by Thatshowiroll View Post
    Would the Shimano XT M-770 shifters work?
    Yes if you're comfortable drilling a couple of holes in your new RD.

  21. #21
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    Quote Originally Posted by gumby. View Post
    Yes if you're comfortable drilling a couple of holes in your new RD.
    What does that mean?

  22. #22
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    Quote Originally Posted by Thatshowiroll View Post
    What does that mean?
    You can get a Shimano 9 speed shifter to work with a Shimano 10spd RD with a well place hole drilled in the RD "arm".

    You can do a "Hack" to get a Sram 9 speed shifter to work with a Shimano 10spd RD.
    Duct tape iz like teh Force. It has a Lite side and a Dark side and it holdz the Universe together.

  23. #23
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    Quote Originally Posted by mitzikatzi View Post
    You can get a Shimano 9 speed shifter to work with a Shimano 10spd RD with a well place hole drilled in the RD "arm".
    There doesn't seem to be much shared on this so I started a thread...

    Shadow + 9 spd Hack

  24. #24
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    Quote Originally Posted by gumby. View Post
    There doesn't seem to be much shared on this so I started a thread...

    Shadow + 9 spd Hack
    Good idea. I could replace the derailleur only and use my current SRAM shifter.

    Gumby. I'm assuming you're using a SRAM 1:1 ratio shifter? Also, I understand the 1st pic, but not clear on the 2nd pic.
    Seriously considering this.

  25. #25
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    Just found this solution, which may be simpler.
    The one with the brass block:
    Hacks: SRAM / Shimano Drivetrain Mix & Match Special Edition

    The idea comes forom a MTBR user named Steevoo.

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