Qui si parla Campagnolo wrote:

Perhaps the 6603 front der which is designed for a 39t middle ring,
with the appropriate ramps to get the chain to the granny.


OH!

Last week I got a 6603 fd and was really surprised to find that it was
incompatible with my old 105 triple crank and chainrings (42t middle).
Now I know why it didn't work. Thanks!