Results 1 to 30 of 30
  1. #1
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367

    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
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    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
    mtbr member
    Reputation:
    Join Date
    Oct 2005
    Posts
    1,000
    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
    mtbr member
    Reputation: J.B. Weld's Avatar
    Join Date
    Aug 2012
    Posts
    5,895
    SGS=long cage and GS is medium cage.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    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
    mtbr member
    Reputation:
    Join Date
    Oct 2010
    Posts
    757
    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
    mtbr member
    Reputation:
    Join Date
    Mar 2008
    Posts
    785
    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
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367

    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
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    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
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    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
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    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
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    2,944
    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
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    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
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    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
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    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
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    2,944
    ^^ 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
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    Thanks. Looks like I'll have to replace everything.

  18. #18
    mtbr member
    Reputation: mitzikatzi's Avatar
    Join Date
    Sep 2008
    Posts
    1,808
    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
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    2,944
    Quote Originally Posted by mitzikatzi View Post
    no!
    Sorry, SRAM Attack. Not their normal line.

  20. #20
    mtbr member
    Reputation:
    Join Date
    Mar 2013
    Posts
    291
    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
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    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
    mtbr member
    Reputation: mitzikatzi's Avatar
    Join Date
    Sep 2008
    Posts
    1,808
    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
    mtbr member
    Reputation:
    Join Date
    Mar 2013
    Posts
    291
    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
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    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
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    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.

  26. #26
    mtbr member
    Reputation:
    Join Date
    Mar 2013
    Posts
    291
    Quote Originally Posted by Thatshowiroll View Post

    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.
    This is Shimano 9 spd shifter, 770 in my case.

  27. #27
    mtbr member
    Reputation: mitzikatzi's Avatar
    Join Date
    Sep 2008
    Posts
    1,808
    Quote Originally Posted by Thatshowiroll View Post
    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.
    Not quite the Sram 9spd 1:1 to slightly different to the Shimano 10spd 1:1 ratio. It is very close. Over 9 changes it is enough of a difference so at the end of the cassette the cog and chain don't line up. Much like using a Shimano 9 spd shifter on an 8 speed cassette. It almost works but not quite.

    To get good shifting with a Sram 9 spd shifter and 10spd Shimano RD you need a spacer hack block as mentioned.

    Other claim the Sram 9spd shifters and Shimano 10spd RD work as they are. The only way to know for sure is to do it yourself. I wouldn't bother.
    Last edited by mitzikatzi; 08-16-2013 at 08:14 PM.
    Duct tape iz like teh Force. It has a Lite side and a Dark side and it holdz the Universe together.

  28. #28
    mtbr member
    Reputation: YJGUY's Avatar
    Join Date
    Mar 2005
    Posts
    45
    Sorry to add onto this but I'm fairly new and had a few questions along the same lines and this saves making a duplicate thread.

    I'm looking to upgrade some drivetrain parts on my 2013 Giant Reign. I'd like to change my rear derailleur to the M786 and use the XT shifter which, from what I understand, is needed. I may also change out the front derailleur and shifter if I can.

    The current specs to my bike:

    - SRAM X7 F/R derailleurs
    - SRAM X5 shifters
    - SRAM PG 1030 11x36, 10-Speed Casette
    - SRAM S1000, 24/38 Crank
    - KMC X10 Chain

    My question is, can I continue using my SRAM casette, chain and crank or do I need to run the complete XT package to get this to work properly with their dyna-sys system? I will probably change everything (crank, chain, casette) in the coming months but would like to start with the rear XT derailleur/shifter for now if I can get away with just that. If not I guess I'll just save up and buy the whole package.

    Another question, I like the gearing I've got and would like to stick with it, would I need a long or medium cage rear derailleur?

    Thanks!

  29. #29
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    1,367
    You should be OK replacing just the RD and shifter.

    As for long or short cage (they call the short one "medium" actually), the medium has a rated capacity of 35 teeth. The formula is

    (big ring - little ring) + (big cog - little cog)

    So you have a 39-tooth capacity.

    The capacities are rated conservatively. I run 37-tooth capacity with a medium-cage and there is plenty of slack to spare. I have been advised here that 39-tooth will actually work, but haven't tried it. It would be marginal. That said, you shouldn't be in the small/small combo anyway.

    But let's see what someone else says.

  30. #30
    mtbr member
    Reputation: Thatshowiroll's Avatar
    Join Date
    Jan 2009
    Posts
    1,439
    Finally got around to doing the hack.
    9 speed SRAM grip shift, chain, and cassette. 10 speed xt shadow plus rear derailleur and 6mm spacer.
    Tried it without the spacer, sucked. Installed the spacer and it worked flawlessly.

    Highly recommended.

Similar Threads

  1. Shadow +
    By DJ/UF in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 0
    Last Post: 08-15-2012, 11:48 AM
  2. xt shadow or xtr shadow rear derailleur
    By scoholofo in forum All Mountain
    Replies: 38
    Last Post: 01-11-2012, 03:49 AM
  3. Shadow or non-Shadow for a low-geared 'cross setup
    By AndrwSwitch in forum Cyclocross
    Replies: 2
    Last Post: 09-27-2011, 08:55 AM
  4. Anyone run the WTB shadow V?
    By RC JonB in forum Weight Weenies
    Replies: 10
    Last Post: 08-08-2011, 08:11 AM
  5. Rear derailleur cable selection XTR triggers to XTR shadow
    By JeffcoHo in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 2
    Last Post: 02-18-2011, 07:44 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •