Why are all car tires black?

The reason for the black color of the tire is because it contains carbon black. This readily available chemical component is used in rubber to form the useful properties of tires. The color of natural rubber is grayish white, even after processing, the color of rubber remains white. Processing means vulcanizing. It is one of the steps in rubber processing.
The problem is that rubber is very flexible, corrosive and highly reactive to heat. Being flexible and responsive to heat, rubber deforms significantly under high loads and temperatures. Tires made of rubber only have a very short lifespan due to corrosion, which is not economically advantageous. For this, suitable chemicals are added to the rubber during the manufacture of tires which increases the life of the rubber by increasing its heat tolerance, load bearing capacity and anti-corrosion.
Carbon black is very useful for this but it darkens the natural greyish white color of the rubber. That is why the color of the tire is black. The change in tire color was first noticed by journalist David Treacy. From 1917, he started using carbon blocks in tires.
There is another reason behind the use of carbon black. During World War I, large quantities of zinc oxide were needed to make bullets, so tire manufacturers were forced to start using carbon black instead of zinc oxide.

Since then, carbon black has been used in tires. However, a small amount of zinc oxide is still used along with the use of carbon black. Currently, about 70 percent of carbon black is used to manufacture tires. As a result, the color of the tire turns black.