Spitfire F4 99a Conical Full 58mm Spitfire Wheels $ 40.00 Default Title - $ 40.00 Quantity This product is currently sold out. Please fill in the form below if you'd like to be notified when it becomes available. Spitfire's premium formula four urethane in a conical shape - A wider version of the Conical Shape. Wide riding surface, cut in sidewalls to decrease weight. A solid, Controllable shape for all terrains. Formula Four Urethane - Resists Flatspotting 58mm Wheel Set of 4. 99a Durometer Full Conical Shape