A wheel assembly (22) includes a rigid wheel (30) and an airless flexible tire (32) with certain performance characteristics of a pneumatic tire. The rigid wheel (30) includes a central portion and a plurality of circumferentially spaced mounting elements ...

A variable-contact wheel (1) comprises a tread (2) having a plurality of radial fins (3) extending parallel to axis of rotation (1a) over at least a fraction of the width of tread (2).