The last mechanical problem that affected me was years ago when my Bebop pedal cleat failed during a ride. Other than that, I have done all sorts of on the road repairs for others. One was repairing a broken chain for a guy who broke his during a ride. I did not have a compatible quick link, so I did the unthinkable by shortening the chain and pushing a rivet back on a 10 speed chain. We were at the start of the ride, so I advised him to head home. Turned out he had fallen and bent teeth on one chainring. He needed a new chain and a new chainring, not possible to correct on the road