A wheel having first and second side walls, first and second shoulders, a crown, a plurality of inner treads, and a plurality of first and second side lugs. The first and second side walls are opposed and define an interior cavity. The first and second shoulders have a generally circular shape and are located at an outer circumference of the first and second side walls, respectively. The crown is located between the first and second shoulders and has a generally concave shape. The plurality of inner treads are located around a periphery of the crown. The plurality of first side lugs are located on an outer surface of the first crown. The plurality of second side lugs are located on an outer surface of the second crown.