12 speed adjustment (chain length)- Mtbr.com
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  1. #1
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    12 speed adjustment (chain length)

    I got my Ibis Ripley LS built with Shimano 12 by my LBS. I have XT shifter and SLX casette (10-51T) and rear deraillure. It has a 32T front ring on XT cranks. It just doesn't shift right. On the stand the 51 clicks and in the mid gears shifting to a smaller ring doesn't shift or is really slow. I adjusted the cable tension, end adjustment screw all over from aligned to the marker to way off. I adjusted the low adjustment bolt all over. Things only get marginally better. My current guess is the chain is too short. I asked the mechanic and he said that he used all the links that came with the SLX chain. I saw a picture at:
    https://dansbikeblog.com/article/how...eed-drivetrain

    My top and bottom positions don't look like this picture. It looks like I have less links.

    Can someone tell me how many links you have for the above teeth counts?

    Help.

    TIA

  2. #2
    Trail Rider
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    Can you post any pictures of your derailleur in those positions?
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  3. #3
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    Check your derailleur hanger with an alignment tool. If that is the issue you won’t ever get it dialed in until you straighten it out. It can cause problems even when the bend is not/barely visible.

  4. #4
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    If the chain is too short it will negatively affect shifting only in the biggest cassette cog. I think your problem is something else.
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  5. #5
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    This sounds like it could be a kinked cable. I see this quite often in the shop. In the lower gears, the kink is outside the housing. As soon as the damaged cable gets in to the housing, the shifting gets slow. A mechanic may reduce cable tension to get it to shift better in the mid/higher gears. When this is done, the derailleur doesn't hit the largest cog correctly and results in the clicking.
    Opinion, but it something I check first when these symptoms exist.

  6. #6
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    All,
    Thanks for all your advice. It was the chain length. I took it to another shop and had to buy a new chain. It was missing 3 links. They also did the checks that was mentioned above.

    Another characteristic of the issue was the up shifts, when it worked, clunked like any SRAM system or a little more that Shimano 11speed.

    Now that everything is fixed the up shifts are amazingly smooth, it is nothing I have experienced. Down shift is a little better than the Shimano 11 speed, which I have always thought was its strong point. For a little while there I was regretting not going with Shimano 11 but now I'm impressed. I hope it holds up reliably but all my Shimano or SRAM have.

  7. #7
    thecentralscrutinizer
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    Yeah, the 12-spd Shimano components are sensitive to chain length and B-adjustment. Once it's set-up though, it is the best shifting system out there. I have my HT and FS bikes switched over.
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  8. #8
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    Do you have to compress the shock and frame like you do with an SRAM 1x installation?

  9. #9
    thecentralscrutinizer
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    Quote Originally Posted by danoiz View Post
    Do you have to compress the shock and frame like you do with an SRAM 1x installation?
    Yes. I've attached the Shimano Derailleur install that has the chain length info in it.

    https://si.shimano.com/pdfs/dm/DM-MARD001-03-ENG.pdf
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  10. #10
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    Thanks, but I already had already read that doc or I wouldn't haven't asked the question. So, I tried it both ways. With the suspension fully compressed, I would need two extra links as opposed to uncompressed so I obviously tried that path first. The chain, however, was too loose and I ended doing as Shimano recommended and everything is good. The Shimano derailleur cage comes a lot more forward than my SRAM ones. Once I got the b-tension set and the shifter cable tension right, everything is working great.

    I paired SLX cassette and derailleur with XT shifter for the multiple down shift. I'm sure this will be blasted as blasphemy here, but it doesn't shift all that much better than my GX grouopsets...which I've had in both 11 and 12 speed. Hell, even my daughter's new bike with SX shifts pretty good. I went the Shimano route to give it a try. I like the downshifts..those seem solid, but upshifts seem a little clunky compared to SRAM. Not trying to start a flame war, but it is what it is. I'll keep fine tuning it over the next week or so. I'm excited to get it out this weekend and break it it. \m/

  11. #11
    thecentralscrutinizer
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    So what were you asking the question above for then?

    It doesn't sound like you have it adjusted right. Maybe you need professional help and a visit to a bike shop.
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  12. #12
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    I'm sure I need professional help, just not sure for bikes. Hahaha!!

  13. #13
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    Quote Originally Posted by mopartodd View Post
    Yes. I've attached the Shimano Derailleur install that has the chain length info in it.

    https://si.shimano.com/pdfs/dm/DM-MARD001-03-ENG.pdf
    No, do not compress the suspension during chain length measurement. See note at the top of page 11 of dealer manual (PDF was at that link).

  14. #14
    thecentralscrutinizer
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    Read the "Notice" on page 12.
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  15. #15
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    Quote Originally Posted by mopartodd View Post
    Read the "Notice" on page 12.
    The "Notice" is post-chain install, post #13 is correct that you do not compress the suspension when sizing the chain.

  16. #16
    thecentralscrutinizer
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    Quote Originally Posted by Dogboy View Post
    The "Notice" is post-chain install, post #13 is correct that you do not compress the suspension when sizing the chain.
    Which doesn't make sense if the chain would be too short after the install. It has me wonder if the manual is correct. Seems like the compressed distance should be the point at which the chain is sized if there is a possibility of it creating a short chain.
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  17. #17
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    Quote Originally Posted by mopartodd View Post
    Which doesn't make sense if the chain would be too short after the install. It has me wonder if the manual is correct. Seems like the compressed distance should be the point at which the chain is sized if there is a possibility of it creating a short chain.
    My experience is that the suggested chain sizing instructions (with a FS bike at full extension) yields an appropriate chain length. Not sure why the "Notice" is even needed, but I'm sure there are some outliers that have more chain growth than average and it may just be a CYA scenario.

  18. #18
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    Quote Originally Posted by mopartodd View Post
    Which doesn't make sense if the chain would be too short after the install. It has me wonder if the manual is correct. Seems like the compressed distance should be the point at which the chain is sized if there is a possibility of it creating a short chain.



    We contacted Shimano and they said the sizing instructions were meant to be done with the suspension uncompressed.
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