Originally Posted by
Bike Gremlin
Based on my theoretical knowledge and practical experience (in other words: "to the best of my knowledge", or "as far as I know"):
as a chain gets worn, at the inner plate - to pin interface, it gets more easily bent sideways (shown in the last picture of chapter 4 in
this article, and the video linked above talks about it).
This makes it more likely to just "bend", when a derailleur pulley pulls/pushes it sideways, instead of staying more straight, following that movement, and making a gear change.
I don't think roller wear has anything to do with that.
Thanks, this is what I thought it was. However, I think that the situation with sideways flexibility is different, in that there is no single reference there, but rather some tolerance interval. When you have a stuck link and work to make it operational, you are working to increase the sideways play. I once got a Wippermann chain and it was horrible on my drivetrain yielding missed rear shifts, etc. The problem that I traced the issue to was that it was too stiff laterally. Sram chains that I used there before were quite flexible and worked great in the same configuration. I was pushing it a bit as I was riding custom cassettes at the time and had to go back to a commercial one just to get through that miserable Wippermann chain, but I never went to the brand again.