Spitfire Formula 4 Lock-Ins Skateboard Wheels - Lock-Ins - 99 Duro

Designed for skaters who demand edge control and consistent performance, the Lock-Ins bring a purpose-built asymmetric profile—straight edge on one side for locked grinds, conical cut on the other for effortless slides. Matched with Spitfire’s Formula Four urethane in 99 duro for lasting speed and flat-spot resistance, these wheels are built for tech, ledges and daily abuse.

Key Features

• Asymmetric “Lock-Ins” Profile: Straight edge side locks into grinds; conical edge supports slides and roll-out
• Formula Four Urethane: Premium compound engineered to resist flat-spots and maintain roll-through sessions
• 99 Duro Hardness: Offers the balance of durability and slide-ability suited to aggressive street skating
• Multiple Size Options: Available in sizes from 53 mm+ allowing choice of setup and feel
• Street-Focused Shape: Narrower contact patch helps with trick control and board response

About Spitfire Wheels

Founded in San Francisco in 1987 by Jim Thiebaud and Fausto Vitello, Spitfire grew out of the streets that shaped modern skateboarding. The brand has always stood for independence and creativity, backing generations of skaters who define the scene through their own style and commitment. Recognised worldwide by the flame logo, Spitfire remains one of skateboarding’s most enduring symbols of identity and culture.