Tire Blacks - ASTM Grades: Carbon black in tire applications can be divided into two basic categories: tread and carcass.  Tread grades are highly reinforcing and can be identified by ASTM numbers in the 100, 200, and 300 series.  These blacks provide improved tread wear of tires as well as traction, cut resistance, and sidewall abrasion resistance.  Carcass grades are semi-reinforcing and are identified by ASTM 500, 600, and 700 series designations.  In tire applications, these carbon blacks are used in the body of the tire where they impact ply strength, hysteresis, and air retention.  In addition, several SR (specialty) grades have been developed for unique applications in tires, both carcass and tread.