[Raybum]

I've been running KMC 8.93 chains exclusively on my SS for about the last 3 years. They're cheap, durable, are reasonably light weight. In the past 2 months, I've busted 2 of the quicklinks as shown below and wondering if it's something I'm doing (ie, chainline, etc), particular to this chain, or an issue with the material of the link.
You can see that the mating link starts to wear a groove and after looking at a bunch of ones in my toolbox, they all also have that save grove.

 

[aerius]

Interesting. I use the same chain on my geared bikes and I just checked a couple worn ones that came off my bikes at the end of last season. The quick link in those chains also have the same grooves worn into them, but it doesn't appear to be nearly as deep as the ones shown in your picture. I can feel it when I run my fingernail across it, I can't really see any differences in thickness or a ridge or anything on the edge of the groove. The groove is a nice polished area and I can feel the edges of it with my fingernail, but that's about it. It also feels like one side of the quicklink is worn more than the other, but I have no idea which way the chain & quicklink was installed on my bike before so it doesn't really help.

A question: You mention that you have a whole bunch of of quicklinks in your toolbox. Are you reusing old quicklinks with new chains or using the fresh link that comes with a new chain?

 

[Raybum]

aerius, thanks for the reply... Yeah, I use the new ones however, this last one that broke was a trail side replacement which was an old one. The first one I broke was a brand new one.
I also noticed the uneven wear side to side. I just put a brand new link on the other day and will have to see what side wears more.