Originally Posted by CRUM
Some hanger/derailleur combo's just do not allow enough adjustment for the B screw to work with the 34 T Cassette. The hangers on the 3D link Rockys have this problem. As a dealer it drove me crazy. I resolved the issue by using a longer screw, bent slightly to engage the stop point on the hanger cleanly. Another possibility is your chain is too long. Put it into the Big/Big combo and see if it is possible to remove one full link. Sometimes removing a full link will create more tension on the derailleur and move the pulley away from the cog.
And as someone else pointed out, this rubbing you are getting is potentially hazardous to your drive train health. I would address it sooner than later.
No, it's not hazardous, and there's nothing I can do about it, it seems, unless the trick with a longer screw works. I'll try that later.
Otherwise, I'll just have to live with it...
