Lately I had a terrible creaking on my road bike, again when I was out of the saddle giving it some welly, it sounded like an old bed, or squeaky floor boards. Sat on the saddle quiet as a mouse, stood up and back again.
Swore blind it was the bottom bracket, anyway after searching on google, tracked it down to over tightened front wheel quick release skewer. So I sprayed a dab of WD40 and then re tightened but not as much, and now gone.
It comes back when I clean the hubs etc and and have to repeat. But I was absolutely 100% certified it was the bottom bracket, which to this day is as silent as a mouse !