Spitfire's Radial Full shape keeps a smooth, rounded edge for a predictable, controlled ride — a classic profile cast in Formula Four, the proprietary urethane Spitfire introduced in 2013 for flatspot resistance and consistent grip. Spitfire's been building wheels like this since Jim Thiebaud founded the company in San Francisco in 1987 under Fausto Vitello and Brian Ware's Deluxe Distribution. This set comes at 54mm, a softer 93a durometer for a smoother ride with added grip.