Brake Dust on Wheels?

[DFB]

Just hoping to have some input on this set of wheels that has me stumped.

To be clear, these are not my wheels, I'm trying to diagnose this issue online, but everything I have suggested so far has not worked. The gentleman insists this is brake dust, but I can't fully determine if it is or not. Apparently, the wheels where ceramic coated about 10 months ago and it would seem this has happened after the coating.

To me, it sort of looks like the paint has worn off, but it also appears to be reacting to an iron remover in the two last pics.

These gloss black wheels are on a Mustang GT with the Brembo brakes.












So far, he has tried the following with a variety of brushes -

- NV Purge (iron remover wheel cleaner)
- Meguiar's Spray Clay Iron Remover
- IPA
- Meguiar's Non-Acid Wheel Cleaner
- Carpro IronX
- Adams Wheel Cleaner
- Brake Buster
- WD40
- CLR

From what I have been told, each product has been used as directed with plenty of dwell time before agitation.

Any suggestions would be most welcome.

[MisterSnoop]

It looks to me like there's a shadow on the inside edge of that where it starts. That would seem to me as of the paint/powder coating is gone.

[Rsurfer]

Are these OEM or after market wheels and how old?

[BLM]

Looks to me like the paint has failed for some reason. It is possible that the failed paint was caused by something that was applied to the wheels but more than likely there was some contaminant on the wheels before they were painted.

[oneheadlite]

Just curious, is it in the “cast off” trajectory of the vents in the rotors?

[chilly]

Just curious, is it in the “cast off” trajectory of the vents in the rotors?

You thinking they got "sandblasted"?

[oneheadlite]

You thinking they got "sandblasted"?

That’s kinda my thought - either from road debris forwarded to the rotors by brake ducting / general air routing, or hot pad material cast off under hard braking.
Under hard braking at night my E36 M3 with aggressive pads would cast a shower of sparks past the windows. (I don’t think any coating would be impervious to hot castoff like that).

In todays age of wanting top tier braking performance with no noise, who knows what sort of concoction the pads are; you might not get aggressive iron remover reaction even if it is pad material. My theory goes mostly out the window though if he’s in no way out hooning.

[BLM]

Due to the position of the damage on the outer/outside lip of the wheels I can't see how it would be from anything cast off of the rotors. The centrifugal forces would cast anything off of the rotors either into the wheel well or depending on what degree the wheel was turned out between the wheel well and the tire.

[Setec Astronomy]

Due to the position of the damage on the outer/outside lip of the wheels I can't see how it would be from anything cast off of the rotors. The centrifugal forces would cast anything off of the rotors either into the wheel well or depending on what degree the wheel was turned out between the wheel well and the tire.

Um...huh? The rotors are inside the wheel, so anything cast off by the rotors...is going to be inside the wheel, not the wheel well, no matter how the wheel is turned.

[DFB]

Ok, some updates after I passed on the theory of paint failure. The wheels are aftermarket from LMR, less than a year old with 10,000 miles on them.

After further investigation, this is not paint failure and definitely something on the surface of the wheel. He has managed to remove the majority of it using a cocktail of chemicals, but has introduced some marring. As you can see from these pics, the material is on the ledge of the spokes.





I'm now suspecting this is from superheated pad material that has fused to the wheels during a track day. The condition of the rotors would indicate this too.

Many thanks for the replies, it has had me stumped.