Postagem original de: lsward ,
I agree with cityzen, but also derailleur hangers are often knocked out of alignment without the owners knowledge. Realigning derailleur hangers require special tools and a true rear wheel. If limit screws are not the problem I would check the alignment of the derailleur hanger by putting the bicycle in the largest chainring on the crankset and the smallest gear in the rear. Visually draw a line from the smallest gear and make sure the smallest gear in the rear lines up vertically with the pulleys in the rear derailleur. If it does not then you may have a derailleur hanger alignment issue. Other things that can cause drivetrain noise are a worn chain, bent derailleur cages, derailleur cable tension, and worn out pulleys on the derailleur. Good luck!