Ricta 50mm Chrome Core Nyjah Huston 81b Skateboard Wheels (Set Of 4) The one and only Nyjah Huston's pro 50mm Chrome Core Rictas. Purple/chrome colored cores with slim, lightweight shape. Core embossed graphics, larger back graphics, 81B White Lightning urethane and 78D durable cores. More resistant to flat spots than any other wheel formula on the market and simply the fastest. Diameter 50mm, Width 28.33mm, Riding Surface 15.24mm