A vehicle track-module including an upper drive wheel, a plurality of idler and bogey wheels, and an endless rubber track with spaced lugs which extends around the wheels and is driven by the drive wheel, which has: a middle main plate with a outer edge of first diameter and inward and outward sides forming the exposed inward and outward surfaces of the drive wheel; drive members axially across and projecting radially beyond the main-plate edge to a second diameter, each drive member having axially inward and outward end portions, a middle portion affixed at its middle position to the main-plate edge, and an outer track-engaging surface; and a rigidity ring affixed to the inward end portions of the drive members and having an inner diameter no less than half the first diameter and an outer diameter no greater than the second diameter. In some embodiments, the axial dimension of the track-engaging surfaces of the drive members is at least 50% greater than the axial dimension of the track lugs. In some, the track module has preferably annular wheel-weights around the central portion of the drive wheel.