Originally Posted by Andrew R Stewart

Yes, the concern of an outer side plate prying off the pin if the peening of the pin's end is damaged is real. Adding to the simple description is that this usually happens when the chain is under a large amount of force. (I know of a guy who broke his pelvic bone when his chain broke). In a shop setting if we couldn't ID the pin and then replace it, the link, properly we would be negligent if we didn't replace the chain.


BTW a very common reason that chains have these problems, links prying off plates and gauges causing tight links, is because of shifting when also powering the pedals a lot. We call this "jam shifting". Modern chain and tooth designs make shifting far more possible in situations that only 20 years ago were considered abusive. That we can shift while standing/climbing up a steep incline or when accelerating from a stop doesn't mean it's the best thing to do or won't result in harm to the chain. Andy.