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.
Tread Width Measuring. Tread width is typically thought of as a measurement between the outboard and inboard edges of a new tire's tread design. Ideally it approximates the width of the tread that comes into contact with the road. Unfortunately measuring tire tread width isn't as simple as laying a ruler across the tread.