Damaged cranks fitting pedals

marathonic

I damaged the crank on my mountain bike fitting new flat pedals (on the wrong side out of pure stupidity).

I've attached a photo. Fitting the clipless pedals (correctly) that actually came with the bike now seems to suggest that what's left of the threads will make for a tight enough fit.

However, I'm concerned that it may be dangerous and come off coming down trails - I'm not sure how much stress is placed on this particular fitting.

If it were you, would you buy a new crank?

Nekarsulm

If you can't afford new cranks, get a tube of that "chemical metal" stuff and pack it in before refitting your pedals. Let it dry thoroughly.
Its surprisingly strong stuff, but to be honest for real peace of mind, get new cranks.

Tigger

you need a helicoil
bring it to a mechanic or engineering shop and they will put one in for you
cost about a fiver if its a reverse thread remember to tell them its reverse thread

don't use chemical metal

onthefringe

if the threads on the pedal reach those last 3 threads- which id say the most certainly will...lash on loctite thread locker and tighten them up as if you are never going to take the pedal off!!
itll stay on..

wav1

Thread is M14 x 1.25..Heli coil as post above will do the job.Easiest to get done if its the right crank.Left [opposite thread]could be harder to get done.Its the same thread as a standard car spark plug.

Mycroft H

Helicoil it. Be as good as the original. Any bike shop worth their salt will have and know how to drill and tap for a helicoil.

onthefringe

reverse thread helicoil a job to find...

Tigger

you can get reverse thread helicoils they make ones for cranks
op is it the left or right crank if you sit on the bike and look down?
left is reversed

onthefringe

you can get them for sure...but the helicoil kit for them work out more than the value of most ordinary cranks!
remember you need a reverse tap as well

marathonic

Thanks all for your comments and suggestions.

I've ordered a new set of pedals so am going to try them as-is with them attached via the final threads visible in the picture in my OP and do some local non-trail runs to see how they hold up. At that point, I'll consider the Helicoil option suggested above.

The primary damage is done to the right hand threads on the crank arm.

07Lapierre

You could try fitting the pedal from the opposite side of the crank. This will re thread the damaged section. Not as good as a helicoil, but it's worth trying.

triggermortis

More than half that thread is gone! I'd rather go with a new crank or a helicoil. You can use chemical metal if you never want to remove the pedal again - I've used to it to 'glue' a cut off bolt into a hole to make a stud on an engine block to mount an exhaust manifold before - so it is strong!