Abstract: A solid tire having a polyurethane foam core is fabricated by first mounting the tire on a two piece jig which simulates the wheel hub on which the tire is to be mounted. This jig is centered on the tire and tightened so that the inside surfaces of the two halves of the jig abut tightly against the tire body. A fill hole for filling the tire with foam is provided on one of the jig halves. A plurality of small holes are formed in the tire in a circle which runs along the high point of the outer surface of the tire, these vent holes being formed on the same side of the tire as the fill hole. The tire is then filled with a mixture of polyol and isocyanate through the fill hole to form a microcellular flexible polyurethane core within the tire. The core material is fed into the tire until the tire is filled a predetermined amount which with the expansion resulting from the chemical reaction, completely fills the tire as evidenced by material existing from the fill hole, at which time the fill hole is plugged.