TT, that's good info, I appreciate it! I've heard about the clearance issues with 530 O-ring chain, but I wasn't aware I could switch to a 520 chain just by switching sprockets as well as the chain.
My chain cleaned up well, but looks can be deceiving.

The next two pictures show how a clean looking chain can be worn to bits!


I haven't been able to find a specification on how long a length of a certain number of links should be to be within spec, but I wrapped the chain around the sprocket and pulled on a link and I'm pretty sure you're not supposed to see daylight through the gap!
Yep, gonna need to order a chain and two new sprockets!
-K