Don Gillies asks "Has anyone on the list ever snapped an alloy or hollow-pin or drillium chain ?? .... What does the crash look like ?? ... in many cases a chain snaps on an uphill climb at low speed, is this the typical failure mode?..."
I can speak to the Everest slotted chain, which I snapped at the end of a slot. And yes, my snapping situation was similar in effect to an uphill climb at low speed which is high pedal pressure. For me (weighing 190 lbs), I was in a high-ish gear standing on the cranks stomping down hard to get going after the light turned green. If you are at the top of the pedal stroke in a standing position and pressing down very hard when suddenly the pedal pressure goes to zero, you have a balance problem as your foot goes down very suddenly while the chain flies off onto the pavement. I managed to get that foot out of the toe clip before falling beyond the point of no recovery and kept stabbing that foot on the pavement until I found my balance by hopping along straddling the bike. It was quite a pas de deux performance for my audience of car drivers, but I did not fall. I retrieved my chain from the middle of the street after traffic passed, and used my multi-tool kit's chain tool to resume the ride. I no longer ride with a slotted chain on a daily rider vintage bike, but I still have several such chains which I may yet use on bikes that I won't pedal stomp.
Peter ................ Peter Brueggeman La Jolla California USA 4peebee(at)peterbrueggeman.com