Cranks fall apart

A ring/nut on the back side of my cranks fell off. What does it do? What do I need to put it back on and how tight?

I got KH Moment cranks. The ring is 1/8" thick has threads on the inside Consequently it is the crank I am learning to crank grab on.

In the picture it is the highlighted part.


It’s a locknut for the pedal thread insert. I would use a pin wrench to put it back on tight, and use thread locker on it as well. Be careful not to get the thread lock into the pedal threads, and it should be good.

hammer & punch?

You might be able to use a hammer and a punch to get it back on, but for sure get some good lock-tight or similar on it.

dunno where the pic is, but jaco_flans just used a piece of wood with 2 nails in it to tighten it…if you dont have that pin wrench thing.

I can post pictures tonight if you want to see the pin wrench I made, it’s really easy to build. I used it for my first KH Moment cranks but I can’t repair my second pair (I’m pretty sure it’s the pedals though). I used to tight my inserts with old spoke! :stuck_out_tongue:

Thanks for the help