Ricta Wheel Dynamics 54mm Maurio McCoy Geo Pro Naturals White Slim featuring 99a high performance urethane for maximum speed, smooth roll, and fewer flat spots. Ricta's lightweight Slim shape features a thinner profile for minimal drag and a medium width riding surface for smooth, predictable slides. Ricta Wheel Dynamics 54mm Maurio McCoy Geo Pro Naturals White Slim featuring 99a high performance urethane for maximum speed, smooth roll, and fewer flat spots. Ricta's lightweight Slim shape features a thinner profile for minimal drag and a medium width riding surface for smooth, predictable slides. Brand Ricta Wheel Diameter (Millimeters) 54.1 Wheel Durometer/Hardness 99a Road Surface (Millimeters) 19.1 Wheel Shape Slim Wheel Width (Millimeters) 31.3