The BB on my road bike has an annoying creak under load, so I stripped it down, greased it all up and put it back together, and that seemed to fix it.

Last week I went out for a couple of hours in the hammering rain, and the squeak now seems to have returned. Sooo… is “squeaking when wet” a plausible BB thing? And if so how do you fix it?

It’s Ultegra BB, screwed in to a Ti frame. The frame has a drain hole in the BB shell, but I’ve left the plastic sleeve installed, which I’m guessing may have trapped some water, and may be creaking as it shifts against the cups.

Thoughts/ experiences/ pointers?