Ricta Sparx Shockwaves 51mm White Skateboard Wheels (Set Of 4) Ricta Sparx Shockwaves 51mm White Skateboard Wheels. Sparx are designed for those seeking the feel of a single pour wheel in a compact shape, whilst still maintaining a standard width road surface. Ricta's signature lightning bolt engraving is sunk into the sidewall and without obtrusive coloring, making these wheels ideally suited to the technical skater who prefers pure and simple, without flashy cartoon graphics. Best of all, Sparx are poured using the Ricta's new leading standard in urethane performance.