Abstract: A cylindrical elongated spacer is welded at one of its ends to an internal flange of the outer rim, the spacer including an inwardly extending split ring member, having a stop adjacent each side of the split and a wedging surface affixed therewithin adjacent the spacer other end, such end being removably engaged against an internal flange of the inner rim, which in turn is backed by a common hub stop. Selective releasable lugs engage against the wedging surface to retain the spacer in such engagement and to connect the spacer to the hub portion.A reinforcing circular member is welded juxtaposed to the spacer other end which also engages against the inner rim flange, and a plurality of arcuate reinforcing members are welded to and between a lip of the outer rim and the spacer.