The game was called ""Mario Kart X"" internally for a while, before deciding on ""Mario Kart Wii"". General producer and Mario creator Shigeru Miyamoto's inputs were limited to new aspects of play such as the Wii Wheel and battles over Nintendo Wi-Fi Connection. The designers tested roughly 30 different prototypes with different shapes, colors and weights (based on real-life go-karts), before deciding on the final Wii Wheel design.