Originally Posted by
Skipjacks
I agree it looks like rubber grime from the brakes. You get the same looking grime if you wet your fingers and run them along your rubber windshield wipers on your car.
But how would it get on the inside of the rim near the spokes? The outward force of the spinning wheel should push anything from the brakes out towards the tire.
The wheels aren't always spinning, at which point gravity takes over and the dingy water drips down to wherever it's going to go?
I have brake dust e'erywhere.