This is an older bike. 1985 Trek 520.

I am needing a left crank arm that will work with a Sakae CR. I cannot find a Sakae CR left crank arm and I don't know if I can just pop something else on there in it's place. This is not a permanent fix, I will be getting the group changed out later on.

I really don't know much but since it is on the left side I didn't see why I couldn't just put any old 170mm crank arm on there.