So heres the story: Yesterday, when riding home, I suddenly started getting a noisy from the crankset/bb area - it sounds like its grinding on something, slightly muted. It only happens when I push pretty hard, mostly on the right, but I can make it happen on the left. Nothing feels different, nothing changed when the noise started.

The only thing I can think of is that the sealed BB has started to dry out. It still spins perfectly smooth though. Everything is tight, as well. Can a sealed bottom bracket dry out, make noise (like the balls in the bearing are being pushed metal-on-metal) and still be smooth?