Originally Posted by
HillRider
Actually road front derailleurs are remarkably tolerant of smaller-than-designed large chain rings. Years ago I bought my son a Trek 1220 which came with Shimano's 3x7 RSX triple group. The chainrings were 46/36/26 but the front derailleur was an RX-100, a 105 triple look alike, designed for a 52T large chainring.
Yes, going smaller is rarely an issue, especially with clamp on FD which can be lowered as much as wanted. I should have been clearer that the limitations on going smaller apply to braze on FDs which often cannot be lowered enough for good shift response