Abstract: Disclosed herein is a method of forming a tire carcass on a porous sand core in the shape of the toroidal member, such method comprising the steps of helically wrapping rubber material about the body of the toroidal member, applying a vacuum through the porous toroidal member to the inner surface of the helically wrapped rubber material, applying force to the outer surface of the rubber material, helically winding wire about the body of the toroidal member over the outer surface of the already-wrapped rubber material, and helically wrapping additional rubber material about and over the wire and first-mentioned rubber material. A vacuum probe is introduced into the area of the helically wound wire, and force is applied to the additional, outer rubber material to urge it against the wire and against the first-mentioned rubber material.