Chains and things
Chain Maintenance. Just replaced my chain. First time I've ever worn one out. I should have checked earlier. I had thought the grinding was due to a loose bottom bracket, but in retrospect, it was probably the chain. That's not mentioned in diagnostic manuals I have. So something for people to watch out for. If you feel like there is a slip and a rumble, it might be the bottom bracket, but it might be the chain. Particularly if it has been 1-2,000 miles since you changed it.
It was very worn out and this article talks all about it. I sure hope I didn't ruin my cassette. That is expensive.