This potent wheel cleaner really gets to work on brake dust, yet it's very kind to the wheels... because it targets the contamination, not the surface underneath.
Unlike the extremely caustic alkaline products on the market (typically marketed as 'acid-free') created because of scaremongering about acids, this wheel cleaner doesn't pretend to be weaker than it really is... It is strong. It is effective. And yes, it is acidic. But the carefully considered formula gives a more measured approach to cleaning wheels, rather than just blasting them with strong chemicals, whatever the pH value. The acids used are designed to attack ferrous deposits from brake discs and brake pads, not the alloy used to create the wheel itself.
For even stronger cleaning of wheels, use the Mellow Yellow concentrate - it's double strength and can be useful to refurbish heavily-soiled rims. Or for a colour change wheel cleaner, showing brake dust removal in action, use Ferrous Dueller instead.