I do pre treat with P21S so not sure if that makes a difference, but inevitably this rust will get slung all over the wheels or sort of leak out if they get wet at all when driving making a clean wheel dirty. Is this normal with cross drilled rotors?

What am I doing wrong?

 

Try blowing the water off with a leaf blower or compressed air before they dry and the iron from the pad/rotors oxidizes.

 

This is normal for any rotor that gets wet and the water sits on there. Even after a hard rain you can see this on rotors. Once you drive and hit the brakes a couple times it will gone.....nothing to worry about

 

Similar to above, I blow my rotors dry at the end of a wash and don't have any rust dust afterwards. I use a MasterBlaster - it's awesome! Between that and spotless rinse, I barely have to touch the car to dry it.

 

happens all the time. i don't clean my wheels until after driving after a wash to get that rust off.

then wipe them down again good after.

 

I always wash the wheels first and use a leaf blower to blow them dry. You can also use Hyde's Rustopper