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  1. #1
    Senior Member vredstein's Avatar
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    Nexus 8-sp won't freewheel

    Just got through cleaning and doing an ATF bath on my Nexus hub. I only disassembled it down to removing the carrier unit. After reassembly, the hub won't freewheel freely. It will freewheel, but with a lot of resistance. Bearing preload doesn't seem to be an issue since I tried installing the wheel with no play and with obvious play. Same issue either way. Any ideas?
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  2. #2
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    Have you done this before? Perhaps you tightened the cones too much? That might do it.

  3. #3
    Senior member Dan Burkhart's Avatar
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    Is it an earlier series hub with pawls rather than roller clutches? If so, you may have dislodged one of the pawls during re-assembly. If it does not feel right, you need to pull the internals again and check it out.
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  4. #4
    Senior Member vredstein's Avatar
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    Quote Originally Posted by 400trix View Post
    Have you done this before? Perhaps you tightened the cones too much? That might do it.
    I disassembled the hub only as far as you did in your second video. The only cone I had to remove and install was the non-drive side cone. I first assembled the hub with it adjusted just to the point where there was zero play. I found the freewheeling drag. I removed the wheel and readjusted the cone so there was play (I could feel the side to side knock once the wheel was installed), and the freewheel drag was still there. The hub shifts fine while on the stand, it rear wheel rotates forward fine and smooth. It's just the backward rotation where the drag is very noticeable. On the stand, I rotated the cranks, let go, and the rear wheel drives the entire drive train including the cranks forward. I can only think a drive side dust cap is making contact with the cog.
    The hub is definitely assembled properly. I double checked it with the exact Shimano Tech doc for the SG-8R36, all dust caps, driver cap, and snap ring are installed correctly in the correct order.
    Last edited by vredstein; 12-25-12 at 10:02 PM.
    "See, it's not that getting wet is a big deal. Really, it's what you're getting wet with.
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  5. #5
    Senior Member vredstein's Avatar
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    Quote Originally Posted by Dan Burkhart View Post
    Is it an earlier series hub with pawls rather than roller clutches? If so, you may have dislodged one of the pawls during re-assembly. If it does not feel right, you need to pull the internals again and check it out.
    It's an SG-8R36 with the roller clutch. I have two of these wheels. I did the ATF bath on both. I'll install the second wheel and see if the same issue comes up.
    "See, it's not that getting wet is a big deal. Really, it's what you're getting wet with.
    Fenders....because it's probably urine."
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  6. #6
    Senior member Dan Burkhart's Avatar
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    Quote Originally Posted by vredstein View Post
    I disassembled the hub only as far as you did in your second video. The only cone I had to remove and install was the non-drive side cone. I first assembled the hub with it adjusted just to the point where there was zero play. I found the freewheeling drag. I removed the wheel and readjusted the cone so there was play (I could feel the side to side knock once the wheel was installed), and the freewheel drag was still there. The hub shifts fine while on the stand, it rear wheel rotates forward fine and smooth. It's just the backward rotation where the drag is very noticeable. On the stand, I rotated the cranks, let go, and the rear wheel drives the entire drive train including the cranks forward. I can only think a drive side dust cap is making contact with the cog.
    The hub is definitely assembled properly. I double checked it with the exact Shimano Tech doc for the SG-8R36, all dust caps, driver cap, and snap ring are installed correctly in the correct order.
    OK, 8R36 rules out a displaced pawl as it doesn't have 'em. Could just be frictional drag between the driver and the dust cap.
    Gearhubs demystified and other cool stuff.


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