Advertise on Bikeforums.net



User Tag List

Results 1 to 7 of 7
  1. #1
    Junior Member
    Join Date
    Apr 2006
    Posts
    12
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Nexus 3-speed very slow to downshift

    I have a Nexus 3-speed hub (on an Electra Amsterdam women's) that is slow to downshift. I've adjusted the tension correctly, I believe, so that the yellow indicator is centered between the lines in second gear. Upshifts are immediate and clean.

    The problem is that when downshifting from third to second, or second to first, the shift is quite delayed -- it often takes several seconds and several rotations of the cranks before the shift actually happens. I've tried adjusting the cable so that it is "closer" to the lower gears, but it doesn't matter. It seems like it's not a problem of the cable pulling correctly, but rather an internal stickiness that causes the shift to take some time to take effect.

    Any suggestions? Thanks!

  2. #2
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    19,585
    Mentioned
    27 Post(s)
    Tagged
    1 Thread(s)
    Shifting in the direction where you're pulling the cable is usually sharper than that there the hub's return spring is. However if the difference is big, it might be that you're not easing off some pedal pressure during the shift. The sliding parts that make the transition from one drive path to the other are under load when you're pedaling and the added friction of the load can be too much for the return spring to overcome.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  3. #3
    Junior Member
    Join Date
    Apr 2006
    Posts
    12
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    Shifting in the direction where you're pulling the cable is usually sharper than that there the hub's return spring is. However if the difference is big, it might be that you're not easing off some pedal pressure during the shift. The sliding parts that make the transition from one drive path to the other are under load when you're pedaling and the added friction of the load can be too much for the return spring to overcome.
    Thanks for the response. It's definitely not just a matter of easing up on the pedals, that doesn't seem to make much difference. I have other 7- and 3-speed Nexus bikes so I'm used to the feel of downshifting and this can be 2 - 5 seconds longer than on those bikes (where it's nearly instantaneous). Maybe it's an issue with the return spring? Maybe I need to lube it inside somehow? Though I hear that is very rarely needed.

  4. #4
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    19,585
    Mentioned
    27 Post(s)
    Tagged
    1 Thread(s)
    Something is making the clutch too sticky for the sprint. Take a minute to work it back and forth off the bike and see if it returns quickly or you can detect the same sluggishness. You don't have to take the wheel off or even disconnect the cable. Simply find a bare area and pull it away from the frame like a bow string and let it snap back.

    If the hub quickly pulls up the slack, then odds are the hub isn't the issue. Check the cable run for a hard bend or crushed housing. Otherwise it might simply be a worn cable housing, or one with dried or sticky lube. Sticky cables are the #1 cause of similar problems on derailleurs, so there's no reason to assume that an IGH would be immune.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  5. #5
    Saving gas on my commute Scooby214's Avatar
    Join Date
    Oct 2010
    Location
    Oklahoma City
    Posts
    508
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I suggest pulling the bell crank off the side of the axle, and trying pushing the shift rod in a few times. If the rod comes back out freely, then your problem is probably in the shifter or cable. If the rod comes out with resistance, the problem is in the rod or in the hub. Check the rod by pulling it out and see if it is coated in a light grey grease. If the rod is not covered in grease, and meets resistance in popping out, you may wish to lube the hub through the shift rod hole.

  6. #6
    tcs
    tcs is offline
    Palmer tcs's Avatar
    Join Date
    Mar 2007
    Location
    Parts unknown
    Posts
    4,142
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think you'll be headed down the right road with the advice so far. Just in case, here's the rebuild/overhaul instructions for the Nexus 3, with a trouble-shooting chart on page 11.
    "When man first set woman on two wheels with a pair of pedals, did he know, I wonder, that he had rent the veil of the harem in twain? A woman on a bicycle has all the world before her where to choose; she can go where she will, no man hindering." The Typewriter Girl, 1899.

    "Every so often a bird gets up and flies some place it's drawn to. I don't suppose it could tell you why, but it does it anyway." Ian Hibell, 1934-2008

  7. #7
    Senior member Dan Burkhart's Avatar
    Join Date
    Oct 2004
    Location
    Oakville Ontario
    Posts
    4,801
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm inclined to think your problem is most likely the shift rod is either bent or gummed up. It's a low normal hub, so upshifts are positive action, downshifts are spring return.
    I'm with the guy that said to pull off the bell crank and pull out the shift rod. Roll it on a flat surface to check that it's straight, and clean and oil it before re installing.
    I've solved many similar issues this way.
    Gearhubs demystified and other cool stuff.


    Rule #12: The correct number of bikes to own is n+1

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •