My old Motobecane 12 speed bike developed a strange, unnerving clicking noise in/near the bottom bracket...although I am not sure what caused it. It always appeared after some warming up/usage. However, strong clicking even occurred when the cranks were in near horizontal position (the right one facing towards the front of the bike). Ironically, the clicking was minor/disappeared when riding with force, e.g. up Edworthy park. Clicking even occured when pedalling slowly to very slowly with next to no force, e.g. when running downhill. One could even try to find the exact location of the cranks when this occurred. Bottome bracket was not loose at all.
Solution: mechanic believed it was due to dried up bearings in the bottom bracket.. it took the remaing grease some time/temperature raise to loose cohesion and fail to lubricate. Bottom bracket and chain were replaced.
Result: was good for 400 kms, then clicking started to occur again after heavy usage (10 km ride)...although the new bottom bracket is sealed. Chain was also well maintained.
Case 2: Exactly the same clicking developed on my 1987 Steve Bauer road bike, which appeared generally in good shape. It first appeared after a ride from downtown to Fish creek...and became successively worse. Bottom bracket appeared to be tight (i.e. not loose). After the winter, the second largest cog in the back developed a strange slippage for no obvious reasons.
Solution: A new set of cogs in the back. Bottom bracket and chain were replaced.
Result: Started slipping on all back cogs, clicking noise worse than ever [does not need any warming up anymore], and rear rim bent after a 2km ride.
Bottom line: this clicking appears to be a common problem, however no one knows where it is really coming from and how to cure it. It is unlikely that the bottom bracket is the culprit. I never had any problems like this with any of my bikes before in 25 years. Got an old Raleigh beater which runs like a charm.
Question: any suggestions?