mystery click when rotating cranks
I was out for a ride yesterday and noticed a "click" sound every three to four seconds, the source of which I have been unable to identify thus far. It's only noticeable when the cranks are in roation, and only when I'm actually riding - just rotating the cranks without a proper weightload on each doesn't replicate the sound.
This morning, I tightened down the screws which hold my toeclips to the pedals. I also removed both crank arms, the bottom bracket spindle and bearing retainers and gave everything a good cleaning and re-greasing. Just put everything back on and went for a quick test ride, and that didn't seem to take care of the problem.
This sound doesn't seem to associate with any particularly noticeable negative effect, it's just that the sound is extremely annoying and, more importantly, it wasn't present until yesterday. I'd rather play it safe and fix it before any really serious problem develops. Any ideas?