Producer Konno wanted to include online features for "Mario Kart DS", but they were left out due to time constraints. These features would, however, be implemented in "Mario Kart Wii". The developers wanted to avoid races becoming more deserted as they progressed, thus altering the online matchmaking to allow players to join a race once it is finished for participation in the next one. The game was the first in the series to feature BMX motorbikes as drivable vehicles, an idea which Konno had proposed since "Double Dash" out of his passion for extreme sports but was rejected due to the seemingly bizarre image of Mario riding a bike. The concept of extreme sports elements was considered in "Mario Kart DS", but due to the difficulty in including the concept in a handheld game, it wasn't able to be implemented until "Wii". Because of the feature's inclusion, the game was briefly known internally under the name ""Mario Kart X"" before its final name was decided upon, referring to the "X" in the word "extreme". The designers tested roughly 30 different prototypes with different shapes, colors, and weights based on real-life go-karts. The final design for the wheel was made to be as lightweight as possible for it to suit long-term periods of gameplay, and it was made entirely white despite experimentation with two-colored designs for it to fit with the color scheme of previous peripherals such as the Wii Zapper and the Wii Balance Board. A blue ring with the Wii logo inside of it was also placed on the backside of the wheel to give spectating players something interesting to look at; as a result, this blue ring ended up being featured in the game's logo.