Cosco carries something called Bio-Eater. It's a bio-degradeable cleaner that my dad turned me on to. I spray it on the wheels when I start to wash my truck and let it soak while I clean the rest of it. Then I use a brush or rag to remove the excess grease, brake dust, road film etc...comes right off! Leaves my wheels shiny and new looking. I've had great luck with it! Give it a shot!
-cbx