The Firestone Firehawk SVX is the ultra high-performance, all-season tire that GMC puts on its Syclone super truck. The aggressive all-season, unidirectional tread design has wide circumferential grooves and lateral slots that combine to provide excellent all-weather traction and help resist hydroplaning. Constructed with polyester cord body piles and two steel belts for added durability and high-speed capability, the Firehawk SVX is available in 65-. 60-, 55- and 50-series sizes. Information: Firestone Tire. Dept. ST09, 1200 Firestone Parkway, Akron, OH 44317-0001, 800/421-6746.