the situation: brand-new jamis nova, compact 105 10-speed, truvativ cranks and chainrings (alu, I think).
On the outside (big) chain-ring, when in the outside (small) gears, the chain falls off to the outside under load. the chain then loops around itself and takes out the front derailleur if I let it. Inexplicably, the f.derr. is not rubbing/overshifting that I can see. chainring bolts are tight.
The bike has a giga-x pipe bottom bracket whose crankbolt wasn't tightened down all the way when the f. derr. was calibrated. I took it back to the LBS to be readjusted when the crank-arm fell off on the way to work, so everything should be fresh and snug.
I don't get it. Chain too tight, maybe?