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Thread: Potenza 11 rear derailleur probelm

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    Default Potenza 11 rear derailleur probelm

    Hey folks,

    I’ve been having some trouble with the Potenza rear mech on one of my bikes lately. While riding the mech will get locked into only working with the large cogs. It won’t shift into the smaller 7 cogs. If I get off the bike and give the parallelogram a strong wiggle it’ll release and then move through the full cassette again.

    I disassembled the derailleur yesterday and found a feature I didn’t know about- moving the outer parallelogram plate drives a rotary mechanism inside the main pivot that tensions the rotary spring in there. Do all derailleurs have this feature or is this a campy thing? Anyway, I cleaned and relubed the whole thing but it is very rough with a serious indent feeling halfway through the parallelogram’s sweep. Any ideas if this is fixable or if this is a common problem with campy mechs? I’m pretty sure the thing is outside of its warranty (this problem first crept in only a few months after I built the bike).

    Crunch cruch, notch notch


    Any advice is appreciated.
    - Brad Comis

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    Default Re: Potenza 11 rear derailleur probelm

    Are you sure it isn't a frayed or kinked cable hanging up in the housing somewhere? That's what it sounds like. It would hang up on a specific gear because of the location of the cable issue in relation to its travel thought the housing. Snags only as the cable is released by the shifter to move the derailleur to a higher gear.

    I'd pull the cable and check it and the housing for issues, especially at the end of the cable that is in the shifter (though this is more of problem spot with some Shimano shifters.)

    As far as the mechanism of the rear derailleur, that's how Campagnolo handles their B-adjustment, if I understand what you are asking. Shimano puts that adjustment in different locations, depending on the generation of derailleur.
    Last edited by j44ke; 05-19-2019 at 08:26 PM.
    Jorn Ake
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    Default Re: Potenza 11 rear derailleur probelm

    If there is something busted in the derailleur, I am going to guess it has something to do with where the spring inserts at either end. You can see on Page 17 of the replacement parts manual the exploded diagram of the Potenza rear derailleur. The parts that might not be to spec are the spring RD-SR008 and the ratchet which comes included with the pulley cage as part RD-PO004. If the spring, when fully loaded (which it would be with the derailleur in the lowest gear) pulls out of the slot at either end, then it might hang until the end pops back into place. The ratchet is one side and then there is a spot inside the "knuckle" on the derailleur body where the end of the spring fits.

    Conceivably, there may be a way to insert the spring wrong way around (might have one end longer than the other to match corresponding slots) so check that. If the short is in the long then it might pull out.
    Jorn Ake
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    Default Re: Potenza 11 rear derailleur probelm

    Sounds to me like the outer face of the parallelogram is bent. If you try to twist the outer pivots you'll realize the outer face can get offset relatively easy.
    you can try to re-jig it by using two small adjustable spanners.
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi così colà dove si puote
    ciò che si vuole, e più non dimandare"

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    Default Re: Potenza 11 rear derailleur probelm

    I had another look at the derailleur on Monday and I couldn't tell if the plates were bent by eye. The hardware went into place without too much trouble, so I suspect that either the plates are straight or they are both bent evenly. The cables are nice and smooth as well (as soon as fully housed cable can be at least).

    Either way the notchy feeling of the derailleur moving across the cassette is very much present. I mounted the mech back onto the bike and it does shift a bit better than before now that is has been cleaned and relubed, but I suspect there will be some hesitancy in the cogs around the middle of the cassette where that notchy friction is present.

    The problem is coming from this internal mechanism inside the main pivot. Here is a rather unfortunate image of the spinna-ma-thing inside the pivot that is driven by the rotation of the outer plate and varies the "B-tension" as the derailleur moves across the cassette. I've finger sketched some rotational arrows in here to kinda-sorta show where that pesky notch is. The spring insertion point is circled. If I move the inner parallelogram plate it is nice and smooth, the pivot at the pulley cage pivot is smooth too.
    https://s4.photobucket.com/user/WheelNut2/media/IMG-9385_zpslktuagbr.jpg.html][IMG]https://i4.photobucket.com/albums/y121/WheelNut2/IMG-9385_zpslktuagbr.jpg
    - Brad Comis

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    Default Re: Potenza 11 rear derailleur probelm

    Campag calls that "planetary gear", not sure the name is correct for the purpose but may give the idea.
    IIRC, it's made of hard resin so my take is that one or more of its teeth have burrs or the whole gear is skewed. Past this, there isn't much to do aside from saving the mech for spares (cage, pulleys, limits screws, bolts, etc.)
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi così colà dove si puote
    ciò che si vuole, e più non dimandare"

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    Default Re: Potenza 11 rear derailleur probelm

    I just had the same problem on a Campagnolo Chorus 11 speed rear derailleur. Something in the "planetary gear" mechanism was jamming causing the derailleur to make an audible click and stick in a couple of spots. Realizing it could not be disassembled to access the mechanism I took it apart enough to access the spring seat, jam a hex wrench in there to stop the spring seat from rotating, and forcefully moved the link that is connected to it. Hearing a couple of loud crunches told me I broke whatever is in there. Success. The derailleur now works with no binding, although without the variable spring tension mechanism. It seems to actually shift better this way.
    Jon Kendziera
    Jonny Cycles

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