The 540 is designed for extremely soft terrain, such as mud and sand. Wide spaced knobs shed mud quickly. Tall aggressive tread pattern for increased traction in the nastiest conditions. Note: NHS (NOT for Highway Service). Tire Specifications: Speed/load rating: 42M. Permitted rim size (inches): 1.40 - 1.85. Outside diameter (inches): 24.53. Width (inches): 2.72. Maximum load (pounds): N/A @ 33 PSI. Construction: Tube type.