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  1. #1
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    Nexus 8 twist shift, need help fixing

    I have a Townie 8 with the Nexus hub and twist shifter. I was experiencing a bit of delayed shifting, but today things went from not great to bad to worse. The shifter seems to have bit the dust, but I'm hoping it can be rebuilt. It no longer twists through all 8 gears, just the first one or two. Seems like some kind of cog came loose or something and it got all messed up. I haven't wrenched on a bike for 30 years, so I'm well out of my comfort zone. Still, I'd like to at least poke around a little in there and see what's what. Can anyone point me to information about how to take these apart without having them explode, and of course, how to reassemble?
    Thank,
    Dan (a very new member)

  2. #2
    Senior Member bikeman715's Avatar
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    check out shimano.com or parktools.com, they should help with what you are looking for. good luck

  3. #3
    cab horn
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    Quote Originally Posted by whizfish View Post
    I have a Townie 8 with the Nexus hub and twist shifter. I was experiencing a bit of delayed shifting, but today things went from not great to bad to worse. The shifter seems to have bit the dust, but I'm hoping it can be rebuilt. It no longer twists through all 8 gears, just the first one or two. Seems like some kind of cog came loose or something and it got all messed up. I haven't wrenched on a bike for 30 years, so I'm well out of my comfort zone. Still, I'd like to at least poke around a little in there and see what's what. Can anyone point me to information about how to take these apart without having them explode, and of course, how to reassemble?
    Thank,
    Dan (a very new member)
    http://www.sheldonbrown.com/nexus-mech.html

    First thing you need to do is ascertain whether or not it's the shifter that is messed or if your cable/housing is fouled.

    So remove the cable/housing from the equation and try dry firing the shifter with it (cable/housing) removed.

    I'm *think* you can find the shifter exploded/service manual on the shimano techinical documents website, but I doubt it.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  4. #4
    Senior member Dan Burkhart's Avatar
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    Quote Originally Posted by operator View Post
    http://www.sheldonbrown.com/nexus-mech.html

    First thing you need to do is ascertain whether or not it's the shifter that is messed or if your cable/housing is fouled.

    So remove the cable/housing from the equation and try dry firing the shifter with it (cable/housing) removed.

    I'm *think* you can find the shifter exploded/service manual on the shimano techinical documents website, but I doubt it.
    I think Operator has hit on the likely cause of the OP's problem. First thing to look for is to see if the wires in the cable housing have pushed through the ferrule in the shifter cable stop. When that happens, the shifter will exhibit the symptoms the OP described.
    Gearhubs demystified and other cool stuff.


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  5. #5
    Broom Wagon Fodder reverborama's Avatar
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    I would say the most likely problem is in your cable. Look for the small arm that comes out of the right side of the hub The cable housing should go into that and it should stretch the cable out. If the housing is out of there, it could do what you're describing. You'll need to shift to first to get the maximum amount of slack to get it back in there. You might also need to adjust it at the shifter with the barrel adjuster. If it all looks like it is in the right spots, put it in fourth and adjust it with the barrel adjuster until the two marks align in the window on the top of the right side of the hub.

    This is all very difficult to describe. A bike shop should be able to sort it out very quickly. I would be surprised if the problem is not in the cable.

  6. #6
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    Thanks for all the replies. I'm embarrassed, relieved, and throroughly mystified to say that I took it into a shop and the mechanic just grabbed the shifter, gave it a few twists, and all was well again. I honestly have no clue how to explain this because it was quite resistant to shifting in my hands, to the point where I feared damaging it if I used any more force. Either he used more force, or the problem had cured itself before I showed it to him. With a little luck it will stay cured.
    Thanks again,
    Dan

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