A novel mountain snowmobile comprises a frame, an engine disposed on the frame, at least one ski disposed on the frame, a seat disposed on the frame, a steering device disposed on the frame forward of the seat that is operatively connected to the at least one ski for steering the snowmobile, and a novel long length drive track disposed below the frame and connected operatively to the engine for propulsion of the snowmobile. The novel drive track comprises an endless body having a ground-engaging outer surface with a central portion flanked by first and second lateral portions, a plurality of longitudinally spaced reinforcing rods disposed in the body along a transverse direction of the body. The rods define a plurality of pitches, and a plurality of profiles project from the outer surface of the body along the plurality of pitches. A plurality of non-profile regions is defined along the plurality of pitches, and the profiles and profile-free regions define a pattern for each pitch. The pitch pattern for the novel track has a six pitch tread pattern which repeats every successive sixsomes of pitches. A height profile that varies between the first and second lateral portions is defined by the profiles. Such height profile has each profile with a height of not less than about 1 inches. The long length track has a length greater than about 141 inches.