An underground mine tire 20 having a nominal bead diameter of 20.0 inches or less has a carcass, a tread 25 and a pair of rubber sidewalls 23, each extending along the outer periphery of the carcass 21 below the tread 25. The tire 20 has a nominal bead width D greater than 8.50 inches and an overall diameter of less than 55 inches. The carcass 21 has at least one radial steel cord reinforced ply 24.