A drain hole at the bottom of the BB would be a good idea since moisture will almost always find a way in and needs a way to escape and seeing how you have holes for the other connecting tubes to the BB they may be open from the top as well and will just pool moisture if the BB holes are plugged. I really don't understand why mfrs. don't put drain holes in all frames, seems like a no brainer.
Last edited by Crankycrank; 10-02-14 at 09:27 AM.