Front derailleur rubs against chain once per rotation, bent crankset or warped BB?
Hi, there's a really annoying "screeching" sound that comes from the chain hitting the front derailleur at the same spot in the pedal rotation. When I'm riding and I look down at the gears, it's noticeable that the 3 chainrings up front sway laterally from left to right to left (and so on) while pedaling. Any ideas if it's a bent crankset or broken BB? I'd take a photo, but it's not that easy to see from a picture..
Thanks
-Antron