hoop, ring - a rigid circular band of metal or wood or other material used for holding or fastening or hanging or pulling; "there was still a rusty iron hoop for tying a horse"

spoke, radius - support consisting of a radial member of a wheel joining the hub to the rim

waggon, wagon - any of various kinds of wheeled vehicles drawn by a horse or tractor

wagon tire - a metal hoop forming the tread of a wheel

wheel - a simple machine consisting of a circular frame with spokes (or a solid disc) that can rotate on a shaft or axle (as in vehicles or other machines)