Snapped crank

JonS123
JonS123 Posts: 171
edited April 2014 in The workshop
So while pulling away at a roundabout, as I pulled away my crank snapped! Nothing to suggest anything was up before it happened, just bang and it went. Lucky for me no cars were behind me when it happened as I did swerve a bit.

What would cause it to fail? Bikes nearly 5 years old but I'd never expect a crank to just go like that.

Comments

  • The Rookie
    The Rookie Posts: 27,812
    Looks like it's been a little loose and started a crack....but the picture isn't really much use as the quality is poor.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • heez29
    heez29 Posts: 612
    Is that where the pedal sits? Cant see clearly enough.

    Could of had pedal strike and its just worked itself worse and worse then finally went pop.
  • MichaelW
    MichaelW Posts: 2,164
    Cracking affects cranks of all quality levels inc high end.
    A crack can propagate from a notch in the aluminium.
    the crank stays in one piece with a hairline crack until the final sliver gives way under load. Is part of the cracked surface silver and part dulled/oxidized?

Categories