i don't have any evidence, (mostly because it would be left behind in the street) and i do agree that most masterlink problems occur due to improper installation.
despite that, bikes get pedaled backwards all the time, whether it be a couple of inches with a coaster brake, or setting up your pedals with a freewheel. there's always a chance of it contacting something and coming apart.
chain sway, or any other side to side deflection can pop that clip off.
i dunno if they still make them, but they used to have chains where the master link was only 2 pieces, and the flat clip part had holes slightly smaller than the rest, so you'd bend your chain sideways to install it, then the tension of the chain held it together. those s*cked.
on old bikes i've bought in the past, with old, rusty, stretched out chains, i've had the masterlink fail completely. granted, they're already old and rusty, but the chain was still usable.
in my BMX days, where a chain takes a lot more abuse than on a normal cruiser's chain, i've seen master links get literally ripped apart. like all the chain stretch concentrated in one point, the masterlink.
anyone remember old bmx chains that used a tiny little nut and bolt in the masterlink? those were cool.
anyway, my opinion is to get rid of the thing, as it's one more thing that can fail.
not to mention, this thread was about where to get a chain breaker for cheap, that'll work on both of your chains, regardless of if you use a masterlink or not.
so there.
(what happened to his E-brakes? Feets r good lol)
