Earl
You make a good point, however if rocker panels hitting the wheels were enough then the car wash equipment manufacturers would not be spending all their R&D to develop brushes that clean wheels specificially.
As they say, what goes around, comes around. When I was with Hanna back in the 70's we had wheel brushes that were 13" in diameter and staggered brushes a combo of 13" and 8" to clean wheels. They came, they went and now they are back as something new.
My experience with foam was less than satisfactory, on the wraps it did not clean well at all. The only thing that got the oil film and dirt off was cloth.
Which leads me back to the original point, the chemical is most important in cleaning the wheels.
In my opinion, of course.
Bud A