I've always had a slight "grinding" noise when in the largest sprocket in back. Did some investigation on-line and it seems my "B" screw needs to be tighted. The jockey wheel seems too close when in the biggest gear. Trouble is, the "B" screw is already in as far as it can go. Ultegra RD.
Almost looks like I need to loosen the RD and "rotate" it so that the "B" screw actually has some room to be useful, but not sure.
What the suggested "next step"?