An adjustable rim includes a first annular ring rotatable about a first axis, the first ring having radially extending first linear slots circumferentially spaced about the first ring, a first annular adjustment hoop rotatable about the first axis, the first hoop having circumferentially and radially extending first arcuate slots spaced about the first hoop, a second annular ring rotatable about a second axis, the second ring having radially extending second linear slots circumferentially spaced about the second ring, a second annular adjustment hoop rotatable about the second axis, the second hoop having circumferentially and radially extending second arcuate slots spaced about the second hoop, and an axially extending arcuate member having a first axial end and a second axial end. The first axial end is circumferentially and radially aligned with a first linear slot of the first annular ring and a first arcuate slot of the first annular hoop. The first linear slot and the first arcuate slot interact to move part of the arcuate member in only a radial direction.