I use wheel scrubber brushes from Griots Garage - they have a long handled version that reaches over the 8 inch rear wheel. I also remove clean and wax my wheels every spring and that helps keep them easy to clean. I wax the inside of the rims also...

 

hey- blanked out and dont know why i didnt post this before-

but

when i got my foamer, i reported that the best use of it was for the wheels... it allows you to get soap in parts of the wheels that you cant get normally, unless you take them off of the car.
so i want to add that the second choice (taking them off of the car is first choice) is the foamer-