new derailleur for vintage bike
I'm thinking about buying a new RD for my '84 fuji del rey. It's already got around $470 in upgrades; the only things that aren't new are the frame set, FD and crank set. The RD pulleys are getting wobbly, and I can't use my smallest sprocket because of vibrations on the pulleys. But I'm wondering whether I should get sora, tiagra, or just something cheap that works. For commuting purposes, the weight isn't a factor. I'm more worried about durability, longevity, and overall quality.
Does anyone have suggestions?