Elastomer insert for supporting a tyre and mounted assembly including the same

The insert has a radial inner face for surmounting a wheel rim (20) receiving a tire (10). Inflatable circumferential cavity (4) is adapted to be inflated by an inflation valve (26) of an independent wheel of the insert by an inflation gas supply unit (8) emerging on an inner radial face and into the cavity and by a discharge unit (9) that discharges the inflation gas outside the cavity. The cavity and the gas supply and discharge units are arranged into and/or on the insert. The cavity is formed by an inner volume in a core of the insert or by a concave outer surface of the insert. An independent claim is also included for a mounted assembly for a power lift lorry or handling equipment, comprising a support insert.