Stripped Crank Removal

wiltonjh
wiltonjh Posts: 59
edited July 2008 in MTB workshop & tech
Okay, whichever muppet I bought my frame and cranks from has stripped them. I've tried using a crank puller but there's absolutely nothing left to pull :x
So, I need to get my cranks off (I don't want to destroy them, I've got to use them for another weekend before I get a new chainset).
Anyone got any tips? I'm thinking either some cushioning, wood and a hammer, or a flywheel puller; those are the 'alternative' methods I've heard of before.

Thanks

Comments

  • nicklouse
    nicklouse Posts: 50,675
    why do you want to take them off, to then refit and then struggle to take them off again?

    and what are the cranks?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • wiltonjh
    wiltonjh Posts: 59
    You make a very good point. I'm travelling to blandford forum (a dh course) on friday, for a weekend with my buddies, and the old chainguide constantly sucks the chain in, which is usually a b**ch to pull back out. I want to fit a new chainguide just for the weekend. On second thoughts though, I think I'm going to have quite a lot of trouble finding a new 5-arm crankset, as they're all but extinct now - sigh.
    I'm not really sure what to do at the moment....
  • nicklouse
    nicklouse Posts: 50,675
    i would be looking at any possible way to sort the device without trying to remove the arm.

    as it is a 5 arm i am guessing it is a Square taper fit?

    a three armed bearing puller MAY help IF you can get a grip and not damage the spider.

    riding around with the bolt out works but can damage the interface resulting in an arm the comes loose.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • wiltonjh
    wiltonjh Posts: 59
    Yeah, I've heard that the "ride with it loose" method can screw the BB just a little bit :)

    I think what I'm going to do is see if i can get a 5-bolt spider in time, if so then i'll smack the old arms off and leave them off. I've got some arms that should do the trick, I hope.
  • nicklouse
    nicklouse Posts: 50,675
    the riding about does not damage the axle, but it can the arms.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • wiltonjh
    wiltonjh Posts: 59
    Okay. Just went and checked, and actually the other arms won't do. In that case, I think it's going to be brute force to get them off. I'll upgrade the whole drivetrain some other time.
    Thanks for your help, Nick.
  • robbarker
    robbarker Posts: 1,367
    Forget refitting them. It's angle grinder fun time, followed quickly by new bottom bracket and chainset.
  • wiltonjh
    wiltonjh Posts: 59
    I'm going to go to an auto parts store tomorrow and buy a gear puller, I reckon that'll get them off and avoid any damage, as it doesn't put any lateral strain on the cranks.
  • mba007
    mba007 Posts: 95
    Good luck with the gear puller. The biggest problem I had was that it couldn't grip the slightly curved corners of the crank. The solution was to give up on the gear puller and instead give it 20 seconds of hammering. I had planned to installed a new BB so wasn't concerned about damage to the bearings.
  • wiltonjh
    wiltonjh Posts: 59
    Okay, well i've tried the gear puller - sorted the problem of not being able to grip it by putting two little spanners between the spider's arms, giving two bars for the puller to grip. Problem is, before the cranks came off, I started to bend the spider's arms. Unbent them and decided not to try that method again. I've got another BB on standby, so that's not a problem. I've got another theory though.
    The crank threads are only stripped on the driveside. If I took off the left hand crank, and undid the BB, would i be able to push the BB out through the other side of the frame, right hand crank and all?
  • nicklouse
    nicklouse Posts: 50,675
    but how will you undo the right hand cup? it is normally part of the whole bb casing.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • wiltonjh
    wiltonjh Posts: 59
    Okay, so to get the BB out I need to undo both sides of it? That was what i was wondering. Is it threaded to the frame?
  • cee
    cee Posts: 4,553
    it should thread into the BB shell yes.
    Whenever I see an adult on a bicycle, I believe in the future of the human race.

    H.G. Wells.
  • wiltonjh
    wiltonjh Posts: 59
    Okay, screw it. I'm gonna borrow a friend's bike for the weekend, angle grind the cranks off mine next week, and put the new cranks and BB on some time later. Now I just need to buy a new chainguide - I'd just bought a 5 bolt CD one, and now I'll need a 4-bolt >.<