Hi, I'm having a problem with my girlfriend's bike. Under load in the smallest gear it drops the chain off the inside within a couple of revolutions. It's not the derailer, it happens without the cage touching the chain. All the chainring bolts are tight. The rings are Biopace. I can't see what's happening. Help please.

Any chance your bottom bracket is slightly loose to create some play for auto shifting? Otherwise, I'd tighten the limit screw on your FD so that the chain DOES rub on that smallest chainring, and then back it off slightly, ride it, see what happens.

Neal