Originally Posted by
cuevélo
But you will have to change your front shifter to a double.
Nope, 105 9 speed front shifter handles double and triple. Only 9 speed dura ace was 2 or 3 specific. Gonna also need an external bearing bottom bracket for your new crank. Might look around (Nashbar, eBay) and try to snag a NOS 9 speed 105r double crank for under 50 bucks)