One wheel is dirtier/blacker than the rest

[Cduncan133]

Not sure what's causing this but one wheel on the front has some black dirt or whatever. The rest don't. What could be causing this? I took it to the car wash 4 days ago and that one rim/wheel is back to being covered in dirt again.

Edit: it's actually both my front wheels. The left side is pretty dirty but the right side is even dirtier.

Thanks!

 

[Accarguy]

That is most commonly caused by cheap or warn out brake pads. That is the brake dust you are seeing build up on the rim. New brakes in the front and you will be all good.

 

[rwt101]

The front brakes do most of the work in stopping your car. But it can also be a caliper sticking. But more than likely it is just the brake dust you are seeing.
Bob T

 

[p71]

Check the pads for even wear on both front wheels, if they are not about the same on both sides, a caliper is sticking. The inner pads tend to wear just a little bit faster than the outer pad, so you must take off the wheels to see, I had one inner pad worn down to the backing plate in less than 6k miles from new due to a stuck caliper, the outer pad only looked about 1/4 worn. With a stuck caliper, you might also be able to notice that rotor and wheel is much hotter than the others after a brief drive.

Semimetallic pads leave black brake dust, switch to a ceramic brake pad for less visible dust.