variable chain tension

scruffyduncan
scruffyduncan Posts: 246
edited July 2010 in Road general
My chain tension varies considerably between different point on the pedal stroke. This has always happened to an extent, but is now marked. I can only imagine this means my chainwheel is not round. Does anyone know of coomon reasons for this and ways of correcting it?

Comments

  • salsarider79
    salsarider79 Posts: 828
    Wear on one or more parts of the drivetrain. When parts are made they have tolerence levels, i.e. that they are produced to within 1mm of perfect. Over time, and especially if the chain has been tightened so that at some points the chain is over tight, it will cause said problems.
    Correcting it:
    1. replace parts
    2. chain tensioner (a sprung one.)

    Though the second one depends on set up, fixed or free, gear hanger or not, etc.
    jedster wrote:
    Just off to contemplate my own mortality and inevitable descent into decrepedness.
    FCN 3 or 4 on road depending on clothing
    FCN 8 off road because I'm too old to go racing around.
  • GarethPJ
    GarethPJ Posts: 295
    Oval chainring like a biopace or something?

    IGMC
  • mankybianchi
    mankybianchi Posts: 117
    Have a look at this link from Sheldon Brown. http://sheldonbrown.com/fixed.html Scroll down to cahin tension.

    Problems can also be due to cheaper quality pressed sprockets which aren't truly round.

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