The primary contributor of skin color is the pigment known as melanin. The quantity of melanin in the skin varies based on genetic factors and is also dependent on the degree of sun exposure. Melanin is produced by specialized pigment cells known as melanocytes.
Average new tires used on cars typically start with 10/32 to 11/32 of original tread depth. Tires are considered worn out. In most States when they reach 2/32 of remaining tread depth. Ans 2 - Here in Canada (and I'm sure in many parts of the US ) we get a lot of rain.
How to check your tire tread depth. Tire tread depth gauges are a fast and easy way for you to know for sure if your tires are safe or if they need to be replaced. Find the shallowest groove of the tread and insert the pin of the gauge until the base is flush with the tire.