The Spitfire Formula Four Classic 99a
skateboard wheels have a narrower contact patch, which has become the standard shape for street skating. Spitfire released their new Formula Four wheels a few years ago now. The latest formula was designed for higher abrasion resistance. This means it is a little harder to flat spot. Formula Four 99a
wheels are generally decorated with a red themed graphic. Unless of course it is one of the signature wheels. The signature wheels feature artwork custom designed for each rider. 99a is the hardest wheel in the modern skateboarding scene.