A wheel assembly including a rigid wheel and a flexible tire. The rigid wheel includes a radially outer rim wall, a plurality of mounting elements, and a plurality of inflatable spacers between the mounting elements. The flexible tire may be mounted on the mounting elements of the rigid wheel such that portions of the flexible tire between the mounting elements are separated from the outer rim wall by spaces between the mounting elements and are configured to flex inwardly when subject to ground engaging pressure. The inflatable spacers limit the amount of inward flex of the inwardly flexible portions of the flexible tire.
