I have an old 80s trek road bike I recently acquired. It's finally getting warm enough to ride it and on one of my first trips it struck me that the noise coming from the rd was louder than I'm used to. I looked it over closely, the chain isnt hitting the cage and seems to be engaging the pulleys correctly, however there is a loud whirring emitted by the chain and lower pulley and no matter how I adjust the gears it doesn't go away. I found a video posted by a fella with the same problem
I also found a couple threads by him searching for a fix, he didnt get one and ended up just replacing the rd and chain. My chain is new so I thought I should ask here before switching out the rd. Any advice?