The present invention is directed to a method for producing a cured tire filling composition and the composition resulting from such a method. A mixture of a polyisocyanate having an average functionality of at least 2.3; a high molecular weight polyol having a hydroxyl number in the range of about 20 to about 31 and having an actual functionality of greater than 2.1; 6 to 65 weight percent of a polar plasticizing extender oil; and no greater than 0.5 weight percent polyamine is cured in the presence of a catalyst to form a polyurethane elastomer having a vertical rebound of greater than about 60% based on ASTM D2632 and a Durometer hardness in the range of about 5 to 60 (Shore A). The mixture is used to fill a tire prior to curing the composition within the tire casing and results in a deflation-proof tire that has considerably longer road testing life than tire filling compositions currently available.