Originally Posted by
dsbrantjr
"Ultegra 6703 derailer says that the minimum difference between the outer and middle ring is 13 teeth"
And the difference between 46 and 40 is 6 teeth, which is less than the specified minimum; this is why the cage is hitting the middle ring.
D'oh! I read 46 and 40 and thought 46/30. I will say, however that the difference my 50/39/28 falls outside the range as well without any issues.