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  1. #1
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    Sram GX drivetrain driving me nuts

    Sram GX Eagle 12 speed drive behaves thus: shift 1 through 5 OK, then 6-7 is a total Charlie Foxtrot, and 8-12 is fine except out of sync with the shifter. That is, 11 on the shifter is 12 on the cog. Checked and meticulously adjusted hanger, tried various cable adjustments, B-screw, stops,etc. WTF? I can move the sweet spot to any 4 o 5 gears I like, but always it seems like the cable moves more than it should.
    Wait, I had an epiphany: the cable is anchored on the wrong side of the clamp screw! Nope. Checked against a friend's X01. Exactly the same.
    Only a couple hundred miles on the bike and it has never been right. Any advise from the wise?

  2. #2
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    The 12 speed can be finicky.....and it's tough to diagnose over the interwebz.
    I am amazed by how bad some shops set it up and give it to customers.
    ( I guess that goes for any groupo or bike)

    Without knowing exactly what or how you adjusted stuff.....there are a ton of set up docs and videos out there.
    A few things are very different from most drive trains

  3. #3
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    The hanger has to be perfect. Check your chain wear. I'm on my 3rd chain since I got my bike in February. Also, these derailleurs seem to bend pretty easy too.

  4. #4
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    The hanger is dead-nuts on per Park hanger gauge. The chain has maybe 200 miles on it and measures barely worn. The H/L stops really don't figure in this behavior, but adjusted anyway. The derailleur 'looks' straight. The upper jockey wheel travels laterally further that the cog is wide. I think the answer may be... SLX.

  5. #5
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    Quote Originally Posted by tyrebyter View Post
    I think the answer may be... SLX.
    Hahahaha! Win!
    I got a bike about a year ago that came with GX EAgle....it took a little work to get it working. But....it didn't blow me away....and seeing all my other bikes are Shimano....
    My 2 main bikes are XTR shifter with XT derailluers
    My 3rd bike has XT shifter with SLX der.....

  6. #6
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    Had a good stare-down with the GX-Spawn-of-Satan last night and we have come to an understanding. You can have all measurable parameters perfect, and still shift like poop. In my case, a key to proper indexing is the angle of the cage. Eyeballing it was inadequate. Trial and error (grabbing and yanking) was required to dial in the indexing, and the whole derailleur is quite sloppy so I can imaging this being a regular thing. I prefer engineering to art in my machines.

  7. #7
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    But...but....how are you going to live with only 11 speeds after enjoying the marvels of 12?
    And I should add...the big reason for me to switch was the GX shifter broke after a few rides. SRAM does have great customer service...because practice makes perfect

  8. #8
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    b screw has to be spot on, they give you a red thingy you hold up to the cassette. I tried fiddling without and got the symptoms you speak of. Cassette has to be tight on xd driver, this also gave me weird shifting as I did not notice a slightly loose cassette.

  9. #9
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    Sounds like you have done all the right things... I would bet the cheezy SRAM cage/carrier assy is twisted slightly. I twisted mine from pulling in debris on 5th ride and it was junk even though there was no visible deformation. I did all the same checks as you but it wouldn't shift properly until I replaced it.

    In my case, this has proven to be a 'regular thing' due to common occurrence of sucking in debris from this low hanging 1X12 SRAM arrangement. After next derailleur failure, I am converting to the more traditional length cage and more economical version of a 1X11 Shimano for this reason. Will go with SRAM 1X11 cassette due to XD hub.
    12 Santa Cruz Heckler
    18 Kona Process 153 AL/DL (27.5)...

  10. #10
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    I think that is the answer.
    Notice the Eagle derailleur shift ratiio is 1.12 while Shimano 11-speed is 1.1. That's pretty close (diff = 1.7%). Anyone try a Shimano derailleur in an Eagle drivetrain? Shimano indicates an 11-speed SLX mid-cage has a 39 tooth range; not quite the 40 tooth span of the Eagle cassette... and not quite $50US.

  11. #11
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    Just don't.
    If you're frustrated with a 12 speed SRAM system.....do you think a SRAM/ Shimano 11/12 Frankenstein set up is going to be bettererer?
    You could always try a JTek ShiftMate with it for a total FUBAR

  12. #12
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    Sounds like you have tried all the adjustments possible. Were they done in the proper order, if so, might try replacing the cables and housing. I had issue with my old Tomac years ago, the LBS replaced the cables and made my Ghost shifting a thing of the past. Just my .02. YMMV
    Let us know how it works out. I just converted to a GX 1x12-so far so go. Might save all of us the same frustration you've been through.

  13. #13
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    Quote Originally Posted by tyrebyter View Post
    Anyone try a Shimano derailleur in an Eagle drivetrain? Shimano indicates an 11-speed SLX mid-cage has a 39 tooth range; not quite the 40 tooth span of the Eagle cassette... and not quite $50US.
    If and when I go away from GX12 Eagle 'debris magnet' I will do what many have done:
    - 1X11 with Shimano XT der (M8000 w/med cage)
    - XT shifter

    The above Shimano 11spd components work fine with SRAM 11spd cassette. I have an XD hub so...
    - SRAM 11spd cassette (10-42)
    - SRAM 11spd chain

    Only thing left is to get similar ratio of my current 10-50 GX12 cassette / 34T chainring, I would change GX Eagle chainring to 32T (SRAM).

    On my previous 26" 3X9 I found the Shimano derailleur worked fine with either SRAM or Shimano cassettes. Same theory goes for the 11 spd.
    12 Santa Cruz Heckler
    18 Kona Process 153 AL/DL (27.5)...

  14. #14
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    Has anyone figured an economical way to get a new 12sp cassette for an XD freehub body? I know the new NX only works with splined hubs, which solves many peoples' problems with upgrading to Eagle. But, am I sentenced to spending $200+ on every new cassette?

  15. #15
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    $80US for a Hope freehub to say 'goodbye XD', and others are similar. But then you're stuck with second-tier 12-speed fodder like Sunrace, or expensive options like e13.

  16. #16
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    Quote Originally Posted by tyrebyter View Post
    $80US for a Hope freehub to say 'goodbye XD', and others are similar. But then you're stuck with second-tier 12-speed fodder like Sunrace, or expensive options like e13.
    Well, there’s the new NX cassette that takes a splined driver. Do you consider that 2nd tier? It’s definitely heavier.

  17. #17
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    Quote Originally Posted by tyrebyter View Post
    Had a good stare-down with the GX-Spawn-of-Satan last night and we have come to an understanding. You can have all measurable parameters perfect, and still shift like poop. In my case, a key to proper indexing is the angle of the cage. Eyeballing it was inadequate. Trial and error (grabbing and yanking) was required to dial in the indexing, and the whole derailleur is quite sloppy so I can imaging this being a regular thing. I prefer engineering to art in my machines.
    Just wondering if the"Grabbing and Yanking" took care of the shifting problems?
    I was able to put on 40 miles this weekend with no issues. Shifting was even better than my Shimano XT 2x10, but 40 miles is not much of a test either.

  18. #18
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    I didn't see what bike, but setting at the proper suspension sag on a full sus is critical too.

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