smontanaro 

Ah, we did not. Thanks for the reminder.

I don't have a decent picture of the setup. I meant to take one before we left the beach house, but forgot until we were home after dark. So, imagine the bike on the rack with a bungie cord through the wheels to keep the front end from flopping around. The two ends of the cord connect right over the front derailleur. My theory is the road vibration over the 2+ hour drive coupled with the slight pressure from the bungie cord served to push the not-quite-tightly-enough secured derailleur down just a skosh, enough that it scraped the large ring on each rotation (demonstrating that the Ofmega-manufactured crank or chainring wasn't perfectly round).

The fix was trivial. Push the shift lever to its limit to slacken the cables a bit, then raise the derailleur slightly, less than a millimeter.

stardognine

Wellyeahbut, there were Bungie cords involved. So it turned out to be a trick question. 🙄😁😉