So i fixed up an old bike recently, and everything was working perfectly until a couple of days ago. Whenever i put pressure on on the crank, forward or back, it makes a wretched clanking/popping noise. I investigated and found that the chain is not seating well on a few parts of the chainring. It is an old stronglight crank and chainring, and i like it a lot, so i want to know if there is anything else to do but get a new crank?

Thanks

Could it be your chain? Is your chain too tight?

Ive tried 2 different chains and cogs as well as tight and loose chains.

A noise in your crank area can come from lots of places: pedals, chainring bolts, bb axle, bb bearings, crank/bb interface on either side.

It is also very very easy to mishear a noise location, so add in cog/freewheel, seat, seatpost, and frame twisting.

I have observed and i am 99% sure it is the crank. Do you think that it could be one of the crank arms is broken or cracked?

Make sure all your **** is lubed and tight.

My phone autocorrects "lubed" to "pubes". Awesome.

If you are sure its your crank than the most likely culprit is the interface between the BB axle and the crank arm.

A crack is possible, but pretty low on the likelyhood. Professional mechanics that have been in it for 30 years still use the process of fixing one thing, checking, fixing the next, etc. Because it is so hard to diagnose the exact location based soley on a sound. There is just so much going on in that area. And lots of problems feel very very similar/ the exact same.

Some towns have places called "bike shops". Maybe you should find one and have them check it out.