The chain on my new bike seems to self coat and generate a black film that finds it's way onto the cassette/gears. Indulge the nooooby ness here please. Is the black coloration from the crank set teeth, which are also black paint ? Metal oxide ? Or just road dust and lube film ? The front gears, the crankset teeth, the I-Tree in Marley-Speak, appear to be painted black. Why would they do this ? - Road Bike ridden about 200 miles to date on dry pavement only.