There is a creaking/squeaking (halfway between each, I would say) sound in my bike. Here is what I know so far:
- Happens during pedaling when the left leg goes down
- Only when I press sufficiently hard on the left pedal
- Not when the pedals are not moving
- There is no discernible issue with the the moving parts involved as far as I can see: on a stand, rotating either pedal moves the wheel freely, with no extra friction that I can feel, the wheel on its own turns freely as well
- The pedal and crank arm are made of some sort of plastic
- I checked Strange long squeal sound when I pedal hard? I can't figure out where it's coming from and I don't think it is the same issue as:
- The squeaking is not very high pitched
- The pedals don't wiggle
- The sound happens exclusively on one side
Based on that, I suspect something is wrong either in the bottom bracket, or in the left crank arm or pedal.
How do I test which part is the issue, and how catastrophically can this fail?
As it turned out, the crank was coming loose. It started unscrewing itself, and eventually fell off. It was hard to understand at first, because I didn't put enough force in trying to see if it was wiggling. I now suppose that it was (just a little), but only when putting my weight on it.