Wheel and tire assembly

A wheel and tire assembly (10) comprises a wheel rim (14). A tire (12) is mounted on the wheel rim (14), the tire (12) and the wheel rim (14) enclosing an annular volume (16). A foam insert (24) only partially fills said annular volume (16), said foam insert (24) displacing air within the annular volume (16) and not being bonded to the tire (12), wherein said foam insert (24) maintaining its shape and its mass distribution within the tire (12).