An assembly (10) for location around a wheel rim (32) comprises an annular support band (12) being formed of a relatively inextensible material. The support band (12) is split at at least one circumferential location to define a pair of opposed ends (16, 18). Adjustment means (24, 26, 28) are operably connected to said opposed ends (16, 18) for enabling adjustment of the diameter of the support band (12), and spacing means (14) depend from the radially inner face (34) of the support band (12). The spacing means (14) is formed from a relatively non-compressible material and, in use, is seated upon the wheel rim (32) to maintain the support band (12) in a spaced apart relationship with the wheel rim (32). The assembly may be adapted for use as a runflat assembly or as a beadlock assembly.