I'm hunting a squeak and think it might be my left crank arm. It only occurs when I pedal and usually doesn't appear until I have ridden for ~1 mile.
Why do I think crankarm? Not many other options and I may be paying for a past sin as well. When I first installed the crank (Campy Centaur square taper), for the first time in years of doing this I didn't get the arm torqued down and it came loose during a ride. I got off the bike right away and did get it torqued down later and thought I "saved" it but the squeak appeared shortly afterwards. (I know that's a bonehead of the 1st magnitude, don't rub it in. )
One mechanic tells me if the crank torqued down OK then I did "save" it and the squeak is elsewhere. Another tells me there was probably a small amount of damage to the square taper that took awhile to manifest. He doesn't seem surprised that I need to ride for awhile before it starts squeaking b/c the taper is just damaged enough that it takes awhile for it to loosen and squeak.
It is not the saddle or seatpost as I've swapped them out and the noise is still there. It's a new BB so I don't think it's there. Chainring bolts are tight as is stem and headset. Have swapped out pedals as well.