The directional pattern of the 520 tire works well in intermediate to hard terrain. Reinforced knobs resist tearing and chunking. Tire designed with a high carbon compound, increasing wear life and minimizing knob edge tear / wear. Note: NHS (NOT for Highway Service). Tire Specifications: Speed/load rating: 51M. Permitted rim size (inches): 1.60 - 2.15. Outside diameter (inches): 27.28. Width (inches): 3.15. Maximum load (pounds): N/A @ 33 PSI. Construction: Tube type.