A wheel assembly comprising: a rigid wheel including - a disc shaped central portion including a plurality of circumferentially spaced flanges corresponding to a radially outer margin of the central portion, and a pair of mounting elements removably attached to each of the flanges, each of the mounting element pairs including a first mounting element removably attached to a first side of the flange and a second mounting element removably attached to a second side of the flange opposite the first side of the flange, the pair of mounting elements presenting an elongated, transversely oriented radially outer edge; and an airless flexible tire mounted on the wheel and engaging the outer edges of the mounting elements such that portions of the tire not engaging the mounting elements are separated radially from the wheel by a space, the portions of the tire not engaging the mounting elements being configured to flex inwardly toward the wheel when subject to ground engaging pressure, the tire including a tension element embedded in the tire and extending longitudinally around the tire, characterized in that the wheel assembly further comprises a first axial side of each outer edge corresponding to a first mounting element of the pair of mounting elements, a second axial side of the outer edge corresponding to a second mounting element of the pair of mounting elements, the second axial side of the outer edge being separated from the first axial side by a space, the tire including an inwardly-extending flange positioned between the first and second sides of the outer edge. a rigid wheel including - a disc shaped central portion including a plurality of circumferentially spaced flanges corresponding to a radially outer margin of the central portion, and a pair of mounting elements removably attached to each of the flanges, each of the mounting element pairs including a first mounting element removably attached to a first side of the flange and a second mounting element removably attached to a second side of the flange opposite the first side of the flange, the pair of mounting elements presenting an elongated, transversely oriented radially outer edge; and a disc shaped central portion including a plurality of circumferentially spaced flanges corresponding to a radially outer margin of the central portion, and a pair of mounting elements removably attached to each of the flanges, each of the mounting element pairs including a first mounting element removably attached to a first side of the flange and a second mounting element removably attached to a second side of the flange opposite the first side of the flange, the pair of mounting elements presenting an elongated, transversely oriented radially outer edge; and an airless flexible tire mounted on the wheel and engaging the outer edges of the mounting elements such that portions of the tire not engaging the mounting elements are separated radially from the wheel by a space, the portions of the tire not engaging the mounting elements being configured to flex inwardly toward the wheel when subject to ground engaging pressure, the tire including a tension element embedded in the tire and extending longitudinally around the tire, characterized in that the wheel assembly further comprises a first axial side of each outer edge corresponding to a first mounting element of the pair of mounting elements, a second axial side of the outer edge corresponding to a second mounting element of the pair of mounting elements, the second axial side of the outer edge being separated from the first axial side by a space, the tire including an inwardly-extending flange positioned between the first and second sides of the outer edge.