Last week I rode another 50km but 1400m of climbing! Thanks to a ride to Gold Hill, which is at elevation ~8000 (feet, not meters!).
About a week ago, my chain started rubbing on my tire and I didn’t know why. It happened after the bike fell over on its side; I assumed maybe my sliding dropouts got out of adjustment? But they seemed ok. Well yesterday morning before my ride I decided to get to the bottom of it. I put the bike on the stand, shifted to gear 1, and pedaled, and I could hear the chain rubbing, but it looked like there was plenty of clearance. After about 10 minutes of head-scratching, I realized the lower part of the chain was rubbing on the tire. Now it all made sense — when the bike fell over I probably bent the derailleur hanger.
Fortunately, last black Friday I stocked up on tools. One of those tools was the Park DAG-1, which is used to align the derailleur hanger. It seemed a little extravagant to purchase a single-purpose tool like that, but reviewers all said that it was a great thing to have, that they found nearly every one of their bikes was out of alignment in some way, and that the tool made them all shift better. Sure enough, the hanger was bent downward, causing the tension pulley of the derailleur to be too far inboard and causing the lower half of the chain to rub on the tire. One tweak and the problem almost went away. Under hard pedaling I can still hear it, but I didn’t want to overdo it the first time. I’ll revisit this later.