Tires were introduced around 1902, and they were made using white rubber. Cars like the 1904 Auburn had been fitted with pure white tires on the front and back. After a few years of use, it was obvious a change was needed. The white rubber tires had extremely poor traction, and in the rain, they were virtually useless. Then the manufacturers started adding carbon black to the white rubber. However, the carbon black was more expensive than the white rubber mixture, so they left the sidewalls white and just used carbon black on the treads. After all, the treads were the only part of the tire that came in contact with the road surface, so the decision was cost effective. That started a variety of tire models created with different amounts of the white walls showing. What was at first an economic feature then became an aesthetic one.