16-09-17, 03:23 PM
I’ve had it happen. It’s just a mild knocking under acceleration (though it was only two missing rollers in my case) and it took quite a careful inspection before I spotted where the problem was.
As for what caused it, I’m usually pretty careful about keeping the chain lubed, this was before fitting a Scottoiler, but the other rollers seemed free enough. A small stone caught between chain and sprocket might have been the start… with a roller gone the next will get a harder impact each time it hits a tooth because the spacing between links doesn’t match that of the teeth.