Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi all,
Vanilla are planning an update to the site on April 24th (next Wednesday). It is a major PHP8 update which is expected to boost performance across the site. The site will be down from 7pm and it is expected to take about an hour to complete. We appreciate your patience during the update.
Thanks all.

Loose crank arm

Options
  • 28-07-2014 10:52am
    #1
    check_six
    Registered Users Posts: 2,245 ✭✭✭


    The non-drive crank on my mtb keeps coming loose. It's at the point now where I'm thinking the splines in the crank arm are worn and this play is causing the crank to loosen.

    I had this problem previously on this bike and I thought I had it fixed when I made sure the crank and axle were spotlessly clean and I put in a new bolt. However, I got my bottom bracket replaced a few weeks back and the crank arm has been working loose on every ride ever since.

    What should I do to fix this problem? Do I just need a new bolt again? Do I need to replace the crank arm? Is it even possible to get a single crank arm?


Comments

  • Options
    #2
    victorcarrera
    Registered Users Posts: 1,059 ✭✭✭victorcarrera


    check_six wrote: »
    ... I thought I had it fixed when I made sure the crank and axle were spotlessly clean and I put in a new bolt....

    Sounds like you have either octalink or FSA cranks. From experience if you or whoever changed the BB don't use a torque wrench or not very experienced at applying the correct torques to crank bolts, pinch bolts and adjusting caps you are very likely to have the problems you describe. That said pedalling a loose crank causes accelerated wear to itself and the BB spindle.


  • Options
    #3
    check_six
    Registered Users Posts: 2,245 ✭✭✭check_six


    I think it's an octalink crank (Shimano BB). This bike doesn't get cycled too often. The crank loosened up right after the bottom bracket was installed in the shop, but I figured it was dirt that was in the crank that was helping it wriggle loose. What kind of torque needs to be on the crank bolt? I have just been trying to tighten it with a good Park Tools hex key, but it's one of the multi-key tools, so it's not that long. I presume they used a long hex wrench in the shop.

    Is it possible to get a single crank arm, I wonder?


  • Options
    #4
    check_six
    Registered Users Posts: 2,245 ✭✭✭check_six


    OK, I think I am back in action. I went to LBS and they recommended getting a proper long handle hex key and some blue threadlock (not red). I gave the long handle hex key a go, and so far so good. I haven't had to try the threadlock stuff yet, but they said to use a small bit and let it set overnight before cycling again.


Advertisement