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New cassette: 11-32 to 11-25……Di2 now not shifting correctly. Any ideas?

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  • July 22, 2018 at 5:52 pm #28753
    rambino

    My bike’s stock componentry was Ultegra Di2 6800 (compact 11-32 / 50-34)

    Last month installed new semi-compact R8000. Chain left as was. Smooth shifting as per usual.  Very happy. All good.

    Two days ago, I ditch the Ultegra cassette/chain and add a shiny new Dura Ace C9000 11-25 cassette and a KMC X11EL (nothing out of the ordinary) – but ever since, the shifting is all out…ESPECIALLY from 11 to 10

    It actually shifts kind of OK between 9 – 1 but no where near as crisp as it was before. No amount of micro shifting does the trick. Basically, if you get it perfect in one area (near enough impossible) it goes out in another.

    For the KMC chain, I have kept the same chain length again – though it was slightly shorter due to old one having 1cm stretch – and visually it looks OK….but I can’t be 100%

    Also, mech hanger looks OK and is unlikely to have been damaged during work being carried out….but again can’t be 100%

    So, I’m confused: too long a rear mech cage… chain compatibility/length… alignment issues…bent hanger or bent cage…..or what?!

    Any ideas?

    Thanks

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  • July 27, 2018 at 8:36 am #923945
    0
    shmooster
    kevvjj wrote:
    If the GS derailleur shifts from 11 -12 then 25 can’t be too small can it. Have a think about it…

     

    I’ve thought about it, still doesn’t make sense.

    July 25, 2018 at 11:24 am #923943
    0
    andsaw

    Try putting chain over big

    Try putting chain over big front ring and big ring on cassette and miss out the rear derailleur altogether and add one full link will be correct length of chain.

    July 25, 2018 at 6:06 am #923941
    0
    CXR94Di2

    Its an odd one, but long cage

    Its an odd one, but long cage derailleurs shouldnt spoil the shifting.  chain length and setup are the usual culprits

    The obvious clue, taking your comment, is that when you change the cass back to the ultegra 11-32 all works fine again.  So the issue points to the DuraAce cassette.  Do you have another 11-25 cass either ultegra or sram to try? 

    July 24, 2018 at 7:57 pm #923939
    0
    Anonymous
    rambino wrote:
    mc wrote:
    Looking at the photos, the B-screw needs adjusted to bring the top jockey wheel nearer the cassette while on the biggest sprocket, however that may mean it fouls on the smaller sprockets.

    The b-screw is currently all the way out – so don’t think I can get it any nearer the cassette. Besides, it doesn’t seem to make a huge amount of difference how the b-screw is set.

     

    kevvjj wrote:
    That chain looks too short by a couple of links at least. That shouldn’t really affect the shifting as much as you state though. Have you played around with the limit screws?

     

    Are you absolutely sure about chain length? Look at how stretched it is in the big-big picture. I’d be worried taking any more off.

    And no, I haven’t fiddled with the limit screws. If memory serves me correct you need to be extra careful with the limit screws on Di2 RD’s? Apparently if not set correctly it can greatly reduce battery life? I’ll have a go anyway.

     

    Thanks

    I think you misread my quote. Indeed I believe the chain needs lengthening – it is currently too short.

    July 24, 2018 at 6:56 pm #923937
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    rambino
    mc wrote:
    Looking at the photos, the B-screw needs adjusted to bring the top jockey wheel nearer the cassette while on the biggest sprocket, however that may mean it fouls on the smaller sprockets.

    The b-screw is currently all the way out – so don’t think I can get it any nearer the cassette. Besides, it doesn’t seem to make a huge amount of difference how the b-screw is set.

     

    kevvjj wrote:
    That chain looks too short by a couple of links at least. That shouldn’t really affect the shifting as much as you state though. Have you played around with the limit screws?

     

    Are you absolutely sure about chain length? Look at how stretched it is in the big-big picture. I’d be worried taking any more off.

    And no, I haven’t fiddled with the limit screws. If memory serves me correct you need to be extra careful with the limit screws on Di2 RD’s? Apparently if not set correctly it can greatly reduce battery life? I’ll have a go anyway.

     

    Thanks

    July 24, 2018 at 6:30 pm #923935
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    mc

    Looking at the photos, the B

    Looking at the photos, the B-screw needs adjusted to bring the top jockey wheel nearer the cassette while on the biggest sprocket, however that may mean it fouls on the smaller sprockets.

    The problem may be the GS is designed to have a higher ramp over the cassette, so with the B-screw adjusted so it clears the small sprockets, the gap is too large on the big sprockets, which can cause imprecise changes/jumping.
    Whereas the SS will be designed to have a shallower ramp, and keep closer to the sprockets. (Ignoring the chain growth problem, if you were to fit it to a wide range cassette and adjust it to clear the large sprocket, it would likely be too far away on the small sprockets, giving shifting problems on the smaller sprockets)

    July 24, 2018 at 6:11 pm #923933
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    Anonymous

    Oh, and if your new chain

    Oh, and if your new chain shifts perfectly on your old cassette then I would also check (as previously advised) the cog orientations on the new cassette.

    July 24, 2018 at 6:08 pm #923931
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    Anonymous

    That chain looks too short by

    That chain looks too short by a couple of links at least. That shouldn’t really affect the shifting as much as you state though. Have you played around with the limit screws? From experience I have found that there is often a subtle difference in overall width between some cassettes and getting the limit screws adjusted makes some difference, especially when shifitng from the biggest cog.

    I really would also check the B screw adjustment too.

    July 24, 2018 at 5:15 pm #923929
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    rambino
    Podc wrote:
    Sorry if this is insulting but is the wheel seated in the drop-outs properly?

    No, not insulting…

    Just a moment ago I removed the wheel, checked the cassette and inspected the dropouts and all looks good.

    Everything should work together fine – compatibility should not be an issue.

    Current and last generation Dura Ace and Ultegra are cross compatible. And the 11spd KMC chain has been specifically designed with these groupsets in mind. It should work!

    I’m almost back to thinking the mech hanger is slightly bent, but …the drivetrain returns to normal if I go back to the ultegra cassette, so it’s unlikely.

    I’d temporarily go back to the 11-32 had I not shortened the chain so damn much!

    I’m totally at a loss. 

    Looking like a LBS trip.

     

     

     

    July 24, 2018 at 3:15 pm #923927
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    Podc

    Sorry if this is insulting

    Sorry if this is insulting but is the wheel seated in the drop-outs properly?

    July 24, 2018 at 2:25 pm #923925
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    rambino

    Yes, I did the cassette

    Yes, I did the cassette myself. 

    Chain definitely 11 spd

    Really can’t see why KMC would make a chain that wasn’t compatible with Shimano 11spd drivechains. I’ve checked online and can’t find any mention of compatiblity issues.

    I bought the cassette, 2 new Corsa G+ clinchers, lates tubes and the KMC X11el chain to breathe new life into my bike’s recently redundant stock DT Swiss RR21 wheels, which had been shod with GP4000 clinchers. The sidewalls had worn through on the Contis so I’d been cycling around on the massively practical Bora 50 tubulars. But get this, after fitting the new tyres, tubes, chain and cassette, I took the bike for a ten minute spin to a mini Sainbury’s. And in that time, all of ten minutes, I somehow managed to destroy both brand new tyres. First the front brake shoe spun around, destroying the tyre wall and buckling the wheel, then, when i got home to inspect the damage, I realised that my rear tyre had a massive gash in it, just above the side wall. Talk about bad luck, right? That or somebody sabotaged my bike whilst I was in Sainsbury’s. Both tyres now complete write-offs. Anyway, this is why I’ve gone back to the really annoying Bora tubulars which you see in the photos. Though, weirdly…the 11-25 shifts slightly better attatched the Campy free hub body than the DT Swiss. Very odd, very confusing and very annoying. I can still ride my bike but the shifts are just very clunky. Forget about shifting out of the saddle whilst attacking a climb! Because hey, that’s always been my strong suite!! Not…

    Now I’m waffling…

    Thanks for the help and advice

    July 24, 2018 at 11:55 am #923923
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    CXR94Di2

    The final photo, there looks
    The final photo, there looks to be plenty of wrap around the 11t cog and the jockey wheel.

    A quick check, you fitted a 11 speed chain not a 10speed? There is a small difference in external width, a chain can sometimes be reluctant to drop down a cog because it’s sits on the edge of the larger cog.

    Did you fit the Cass yourself? Check the cogs are all facing the correct way, eg all numbers face outward

    finally it could be just a compatible issue and kmc doesn’t like the Dura ace cassette

    July 24, 2018 at 11:27 am #923921
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    rambino

    Here you go…

    Here you go…

    July 24, 2018 at 10:55 am #923919
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    CXR94Di2

    the small small photo, the
    the small small photo, the chain looks slack as though the derailleur has no more spring tension. Take one more photo with it big chainring and 11t cog please. I would say chain is too short by one link(2pairs)

    July 24, 2018 at 8:55 am #923917
    0
    rambino

    Small-Small

    Small-Small

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