Originally Posted by Trsnrtr

So, my SRAM eTap rear derailleur started acting up a month or so ago. First, when cornering hard to the right, the chain would shift up and then drop back down after completing the turn. With no cables or anything, I was totally puzzled. Then, about a week ago, the chain started jumping off the lower pulley occasionally. That confused me, too, but I’m easily confused anyway. Today, it started doing it continuously. I finally realized the teeth were looking pretty short. No problem, I happened to have a spare from a destroyed SRAM Red. Same pulley.

I like to keep spares of things that fail so I go online and the pair of jockey wheels are ~$130. WTF? Turns out they have ceramic bearings. I guess it’s too much to ask for a $500 derailleur to have $20 jockey wheels.