Grant Taylor Undead Pro Formual Four Radials Wheels. Spitfire Formula 4 features more speed and control on all surfaces, unmatched flat spot resistance, smooth slip-resistant glide, high rebound compound. 100% True Performance Urethane. Radial Full offers a super wide riding surface with round edges for stability and versatility. 2.185in x 1.370in, with a 0.844in 99A riding surface. Comes packaged with a custom printed Undead patch.