Springy noise - rear mech?

redvision
redvision Posts: 2,958
edited June 2018 in Workshop
I have an annoying noise which has developed on my best bike which i could do with some help solving.
It sounds like a spring or something, and is definitely somewhere on the drivetrain as only occurs when spinning.

I have changed wheels, the chain and cassette but it still persists, so i'm thinking it has to be one of the mechs, even though the gear changes are smooth. I should also add the drivetrain is pretty quiet (a mix of Dura Ace and Ultegra), apart from this springy (my technical term) noise.

Does anyone have any idea why a mech (if it is the mech) would be making this noise and how to stop it?

Thanks

Comments

  • keef66
    keef66 Posts: 13,123
    What happens if you freewheel but still chuck the bike from side to side? And do you get the noise with the bike on the workstand and turning the pedals?

    Is your right foot / crank catching the end of the front mech cable? That can sound a bit twangy on a carbon bike.
  • redvision
    redvision Posts: 2,958
    keef66 wrote:
    What happens if you freewheel but still chuck the bike from side to side? And do you get the noise with the bike on the workstand and turning the pedals?

    Is your right foot / crank catching the end of the front mech cable? That can sound a bit twangy on a carbon bike.

    Thanks for the reply.

    Nope, foot not catching on the mech cable and no noise when freewheeling. Annoyingly i haven't been able to replicate on the workstand.

    The noise is there when I sprint (bike moving side to side) but also when seated.

    Thinking about it, when i drop the power slightly after a hard effort (seated or standing) the springy noise is very audible.