Crank arm and pedal

jdee84
jdee84 Posts: 291
edited August 2016 in Workshop
Was putting pedals back on the bike after being away and from not focusing tried to put the right pedal on the left crank arm. This seems to have rounded the thread in the crank arm and I can't get the pedal in now. Is there anything could be done with this?

Comments

  • fat daddy
    fat daddy Posts: 2,605
    you could re-tap the thread, but you will 1/2" or 9/16" 20tpi tap and die set ... that going to a be a rare bit, but one of the builders might have one.

    IF the thread isn't too beaten up, you might be able to recover it enough by cutting the thread by hand using a sharp tool and working the groove.

    BUT

    in reality, its the perfect time to upgrade to lighter cranks :D
  • laurentian
    laurentian Posts: 2,553
    Can you insert a bolt from the other side of the crank arm? (i.e. not the side where you have buggered the thread). if you get a bolt that is longer than the crank arm is deep and screw it right in and out the other side, it will probably re-tap the thread for you. Be sure to get the same thread as your pedals.
    Wilier Izoard XP
  • trailflow
    trailflow Posts: 1,311
    What crank is it ?
  • jdee84
    jdee84 Posts: 291
    It's a pretty new cannondale sisl crankset! I m an idiot!
  • fat daddy
    fat daddy Posts: 2,605
    how much of the thread is destroyed ? ..... is it along the entire thread or just the beginning bit where you are first trying to get the pedal to bite.

    if its just a short part of the thread I would try cleaning it up with a small sharp screw driver ... ie one of those electrical ones or something you can get into the groove and get rid of any burrs.

    once this has been done try and persevere getting the correct pedal to bit, once the pedal can grab hold of a enough thread its possible you will be able to keep winding it on and off until it re-cuts the thread
  • keef66
    keef66 Posts: 13,123
    You can sometimes recover the thread sufficiently by threading in the (correct) pedal from the back of the crank, then removing it and installing from the correct side.

    Better still, a bike shop should have the correct tap.

    If it's properly buggered, your only option may be to have it helicoiled, which should result in a repair as strong as the original.

    Option D is obviously buying a new crank. Ouch!
  • jdee84
    jdee84 Posts: 291
    keef66 wrote:
    You can sometimes recover the thread sufficiently by threading in the (correct) pedal from the back of the crank, then removing it and installing from the correct side.

    Better still, a bike shop should have the correct tap.

    If it's properly buggered, your only option may be to have it helicoiled, which should result in a repair as strong as the original.

    Option D is obviously buying a new crank. Ouch!


    Should the right pedal from the wrong side of the crank be tightened clockwise or anticlockwise on the NDS?
  • keef66
    keef66 Posts: 13,123
    jdee84 wrote:
    Should the right pedal from the wrong side of the crank be tightened clockwise or anticlockwise on the NDS?

    Look at the thread on the pedal axle; it will be obvious which way to turn it to screw it in.

    Anticlockwise when viewed from the back of the crank I think...
  • redvision
    redvision Posts: 2,958
    Best way to remember which direction to thread the pedals is that, no matter what side of the bike you are on, too tighten them you screw towards the front wheel. To loosen you screw towards the rear wheel.
  • keef66
    keef66 Posts: 13,123
    redvision wrote:
    Best way to remember which direction to thread the pedals is that, no matter what side of the bike you are on, too tighten them you screw towards the front wheel. To loosen you screw towards the rear wheel.

    But the opposite if you're screwing a pedal in from the back of the crank to try and rescue the thread...

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