Originally Posted by Doohickie

I assume you've thoroughly cleaned and lubed the FD. If so, shifting into the small ring when you are pushing hard to climb a hill is shifting too late. Shift to the small chain ring when you are not pedaling hard (i.e., when you're at the bottom of the hill before you start your climb). Unless the return spring or pivots on the FD are broken or gummed up, the problem is your technique. The reason is works on the workstand is that the chain is lightly loaded when you're moving the pedal by hand. Hill climbing is a thinking man's game. You have to anticipate the need for the gear and get to it before the chain is too tight. Once it is, the derailleur spring force is not sufficient to pop it off the chain ring.