The Zombie Aluminum core is machined from a solid billet of aluminum, using the same manufacturing processes as we use to make our famous Power Trac racing plates. This increases strength and allows us to machine the hub to a tighter tolerance than any other hub on the market. Creating the perfect fit between bearing and inner core. Cores are then treated with a special anodizing process to increase hub durability and urethane bonding. This technology is unique to the Zombie wheel line. The urethane used in all Zombie wheels are poured using a precise time schedule to ensue product quality throughout the range.