nexus 8 - requires cable retensioning all the time

Discussion in 'Cycling Equipment' started by CroWizCom, May 9, 2006.

  1. CroWizCom

    CroWizCom Guest

    i have a problem with adjusting gear shifting on nexus 8.
    while slowly breaking in for some 1000km and speed and ease of shifting
    increased from initial 'lazy' shifting.

    however, i am not happy yet.

    i use adjustment barrel to line the lines in 4th gear.
    if i check after while (15km) i notice that they are no longer
    aligned.
    i retension the cable with adjustment barrel, making sure that lines
    are aligned and that cable is stretched. after a while i can no longer
    shift to eight gear because cable is 'too short' and i have to readjust
    tesion / realign the lines.

    there does not appear to be any problem with cable movement and it
    moves with ease.

    its a new cable and new gripshift as provided with the wheel.

    z
     
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  2. jtaylor

    jtaylor Guest

    "CroWizCom" <[email protected]> wrote in message
    news:[email protected]
    > i have a problem with adjusting gear shifting on nexus 8.
    > while slowly breaking in for some 1000km and speed and ease of shifting
    > increased from initial 'lazy' shifting.
    >
    > however, i am not happy yet.
    >
    > i use adjustment barrel to line the lines in 4th gear.
    > if i check after while (15km) i notice that they are no longer
    > aligned.
    > i retension the cable with adjustment barrel, making sure that lines
    > are aligned and that cable is stretched. after a while i can no longer
    > shift to eight gear because cable is 'too short' and i have to readjust
    > tesion / realign the lines.
    >
    > there does not appear to be any problem with cable movement and it
    > moves with ease.
    >
    > its a new cable and new gripshift as provided with the wheel.
    >


    Check that

    a) the cable end is securely fastened; and/or

    b) if there are any guides or pulleys over which the cable runs, that they
    are not insecure and so moving on the frame and reducing the cable run.
     
  3. CroWizCom

    CroWizCom Guest

    it appears that yellow lines (was red dots) align in 5th gear. if i
    realign them back to 4th gear, after a while they are aligned in 3rd.
    so i am screwing adjustment barrel like crazy.

    preety clueless so far. none of potential 'playing' places on cable
    route generate entire gear slip.

    my most recent suspicion is that end bracket is moving up and down

    huh
     
  4. CroWizCom wrote:
    > it appears that yellow lines (was red dots) align in 5th gear. if i
    > realign them back to 4th gear, after a while they are aligned in 3rd.
    > so i am screwing adjustment barrel like crazy.
    >
    > preety clueless so far. none of potential 'playing' places on cable
    > route generate entire gear slip.
    >
    > my most recent suspicion is that end bracket is moving up and down


    Check that the rear axle isn't moving around under load / braking
    (check brake arm if drum-brake). Check length on your axle locks in
    the drop-outs, and tightness. If out, try using a thick grease or
    low-stength locktight? They do vibrate out of alignment (my experience
    from nexus7 in rear horizontal dropouts of a load bike).

    Also check that your headset isn't loose and changing tension.

    yours,
    Sam R.
     
  5. CroWizCom

    CroWizCom Guest

    i could understand that axle could rotate forward a little tightening
    the cable but i dont understand how would it move back? its not loose.
    i have v-brakes.
     
  6. Mike Reed

    Mike Reed Guest

    CroWizCom wrote:
    > i could understand that axle could rotate forward a little tightening
    > the cable but i dont understand how would it move back? its not loose.
    > i have v-brakes.


    Braking puts significant force on the axle. If you draw a tangent
    backwards off the rim from the center of your brake pads, that's the
    direction of the force on the axel generated by braking. The force on
    the axle is close in magnitude to the force on the brakes. With fairly
    steep seat stays, and pad offset from the stays, they can center nearly
    on top of the axle, which means the force would be nearly perfectly
    rearward.

    An axle allowed to move backwards will do so under braking.

    This is one fact that has made me nervous about my friend's Klein with
    rear/down facing dropouts. Plus the fact that it's impossible to remove
    the wheel without touching the chain is just plain lame.

    -Mike
     
  7. CroWizCom

    CroWizCom Guest

    hmm it looks like i switched left and right side anti rotation washers
    because my bike has been upside down when i was applying them. (or was
    i looking at the wheel from the front?)

    they should mark them 'sprocket side' and 'other side' :)

    Mike: during the proces i have found the means of 'removing the wheel
    without touching the chain'. you have to use the chain tensioner :)

    z
     
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