The Greenball HiwayMaster is one of our best selling bias-ply ST tires (Trailer only). It has a simple 5 rib tread pattern that ensures long tread life. The tire also has a strong bias-ply casing for added protection from road hazards and overloading. Because these tires are sold in many different markets around the world, Greenball HiwayMaster tires include metric sizes on the sidewall. For example 7.50-16 is identical to an ST205/90D16, and is marked accordingly.