Originally Posted by Mojo GoGo

So if I understand you correctly (I haven't looked at Madone frame in a year), the external bearing cups thread into the inside of the bottom bracket. So the square taper bottom bracket I'm currently running just needs to be removed from my Allez and should screw into the Madone frame no problem.

(just assumed some sort of backward incompatibility (e.g., external cups having external bottom bracket threading) had been designed in by the manufacturer)