Carlisle Radial Trail RH Trailer Tire - ST225/75R15 D 8 Ply Quiet - Variable pitch tread design minimizes noise generation while enhancing heat dissipation and tread life Durable - Specially blended heat-resistant polymers in the tread compound deliver longer tread life. Independent laboratory tests rank the Radial Trail RH best in extreme heat conditions Handling - Advanced geometry maintains a highly stable tread contact patch for a responsive and sure ride that transmits less vibration to the towing vehicle High-strength steel belts, microfiber reinforcement and optimizes ply construction improve stability for less trailer sway