Originally Posted by
zukahn1
Also it seems a given but have your dropout hanger alignment checked a couple of mm off could result in your problems.
This would apply if the chain were rubbing on the bottom of the rings, but the RD has no control on the top chord's straight run from cassette to chainring.
BTW- we rarely hear of lower chord rub because most hangers are bent in (bike falling over) and this would solve rather than cause the issue.