I apparently over-torqued the crank bolt and it made a loud snapping sound. Now the hex wrench just spins freely and so I can neither tighten nor loosen the bolt. How do I remove the (non-drive side) crank arm? Will a replacement bolt, if available, resolve this issue or have I done more damage than that?

Crank bolt kinda straight on Crank bolt tilted

  • Can you take some pictures? Also, there should be 2 hex bolts on top of each other one a smaller right hand threaded one and a larger left hand threaded. Are you turning the smaller internal one? If you remove the larger external one, you should be able to see what's going on with the internal one a little more clearly, ie. is the head still attached to the thread.
    – alex
    Oct 21, 2014 at 13:50
  • Thanks @alex, I added some photos. I assume if what you say is right about the multiple bolts, it's the external, as it (used to!) tighten clockwise. Oct 21, 2014 at 15:00
  • You have to somehow unscrew the dust cap/"self pulling" cap and use a conventional crank puller. Oct 21, 2014 at 15:18
  • Crank puller won't work as the Ominium is a GXP external BB crankset with a thru axle. The only way is to somehow get the bolt turning anti-clockwise. I think there's a trick for this but I'm not sure what it is. Hopefully the threads on the thru axle aren't damaged and it's only the hex but that's rounded off. Other option is to cut the crank off at the bolt if you don't want to save it!
    – DWGKNZ
    Oct 21, 2014 at 18:41
  • I'd have thought with the bolt out a crank puller would be able to do the job, assuming you can get one in the right sizes.
    – alex
    Oct 22, 2014 at 1:28

2 Answers 2


I brought this to my local bike shop. They were able to get the external bolt off with a larger hex wrench (the bolt is 8mm). Not sure how they got the inner bolt out--I'll edit with an update when I stop by to pick it up after the replacement part comes in tomorrow.


Yes, normally if a bolt get stuck there are 2 possibilities. 1) in shops often they have half measures, like 8 1/2, or even 9 if it is particularly damaged. 2)the best solution I have found to remove bolts has been using glue. So put the bike of its side, so that you can drop the glue in the hex key. Leave it to rest and if the glue is strong enough it will remove. It worked for me a few times.

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