the chainline looks pretty straight. there's maybe a mm of difference, enough so that it rubs ever so slightly on one side of the cog. I'm running a front brake, for sure, and considering front and back, especially after this morning's steep downhill freewheeling.

I think there might be a problem with my crankset, because there's tight spots (2) when I move the pedals through a full rotation. hmm... well, I'll pay more attention on the way home, and see what happens.