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  1. #1
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    9150 Rear Derailleur & Chain

    Hi everyone.

    I have recently installed a 9150 groupset on a new SWorks Roubaix frame and the shifting between the middle few sprockets isn't quite right. Hanger has been checked, chain length is right and I've been over all the Di2 adjustments several times.

    My query is regarding the B-Tension screw which the 9150 manual calls the End Adjust Bolt. If I tighten it to spec and it's real close to the largest sprocket (30 tooth) the shifting is real good, but by the time I shift to about the 6th sprocket, the chain goes loose and sloppy. If I tighten it up again in the lower gear, the shifting is poor.

    These un-sprung 9150 derailleurs are a bit strange because their hanger mount just flops around until you get chain tension on them. Does anyone have any experience with them which you can pass on please?

  2. #2
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    Something is not right, take it back the bike shop and have them take a look.
    BANNED

  3. #3
    'brifter' is a lame word.
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    How do you know your chain length is correct? What method are you using?
    I work for some bike racers
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  4. #4
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    Quote Originally Posted by cxwrench View Post
    How do you know your chain length is correct? What method are you using?
    Straight from the R9150 dealer's manual which is chain around the large chainring and sprocket + 3 pins (1 full link). I then used the Chain Length Calculator app to double check. I think the app uses the Park Tools rigorous equation to calculate the number of links.

    But I think you are on the right track. If the chain had a little more tension in the lower gears it would be ok. I wonder if minus 1 link would help.

  5. #5
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    Shift into the small up front and small in the back.

    What does the rear mech cage and pulleys look like vs. the chain? Anything touching? How much tension is on the cage in this gear?

    Take a picture of it in this gear, the small/small and post it.


    If you haven't guessed yet, I'm telling you to resize your chain using the small/small method.
    use a torque wrench

  6. #6
    'brifter' is a lame word.
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    ^This^. I'm a fan of the longest possible chain.
    I work for some bike racers
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  7. #7
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    Thanks, will do that tonight and post the picture. With the 52/36, 9150 Di2 won't allow me to go fully small/small but I'll post what I see in the smallest sprocket and small chainring.

  8. #8
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    Quote Originally Posted by Rebem View Post
    With the 52/36, 9150 Di2 won't allow me to go fully small/small but I'll post what I see in the smallest sprocket and small chainring.
    Why's that? My 52/36 Ultegra 6870 Di2 allows full cross chaining (big-big or small-small) better than any group I've ever tried. And small-small is very quiet (more so than big-big).

  9. #9
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    The default programming is to restrict it so as not to cross chain. You can remove the restriction but to be honest I don't mind the setting.

  10. #10
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    Quote Originally Posted by Rebem View Post
    The default programming is to restrict it so as not to cross chain. You can remove the restriction but to be honest I don't mind the setting.
    ^this^

  11. #11
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    Spoke to Shimano tech support yesterday and the advice is that the 9150 is sensitive to chain length. Looks like I need a link or two shorter in order to get the chain tension on the smaller sprockets. He suggested placing the bike in the 52/11 combination and observe if the rear pulleys are vertically aligned. Mine aren't - the lower one is slightly further back so I can probably lose a link or two. Will try it over the weekend and report back.

  12. #12
    'brifter' is a lame word.
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    Quote Originally Posted by Rebem View Post
    Spoke to Shimano tech support yesterday and the advice is that the 9150 is sensitive to chain length. Looks like I need a link or two shorter in order to get the chain tension on the smaller sprockets. He suggested placing the bike in the 52/11 combination and observe if the rear pulleys are vertically aligned. Mine aren't - the lower one is slightly further back so I can probably lose a link or two. Will try it over the weekend and report back.
    Put the bike in the work stand. Small/small. Does the chain rub on the rear derailleur anywhere? Like the bottom of the upper pulley? If it doesn't you're good. You can double check this by shifting to big ring. Shift up to the big cog and check the position of the pulley cage. You can hold the chain w/ your fingers and twist it like you're pretending to make the chain shorter. If the pulley cage goes wayyyy forward/up and pedaling the bike by hand doesn't feel smooth then you probably don't want to shorten the chain.

    Remember...just because the guy your spoke to works at Shimano doesn't necessarily mean he has all the right answers.
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  13. #13
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    Quote Originally Posted by Rebem View Post
    The default programming is to restrict it so as not to cross chain. You can remove the restriction but to be honest I don't mind the setting.
    Interesting. Is that only in Synchronous mode or even in manual mode?

  14. #14
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    Quote Originally Posted by LiquidCooled View Post
    Interesting. Is that only in Synchronous mode or even in manual mode?
    All modes to my knowledge. I run in manual and it's there. Synchronous would just handle front-back changes for you and semi-synchro just flicks a couple of sprockets when you change the front chainring.

    @cxwrench - point taken. Checked your suggestion and it was all good. Removed one full link tonight and it's shifting perfectly.

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