Since the Razor came out in the U.S. in the late '90s, inventors have tried, with varying success, to create the next generation of kick-powered conveyance. Now a Nevada start-up aims to beat the Razor in both maneuverability and stability. The Sbyke is a BMX bike mixed with a skateboard. The company claims that the fixed 20-inch wheel allows its scooter to negotiate uneven surfaces better than a Razor. It also says its novel rear-axle mount, which uses ball bearings that let the axle turn up to 50 degrees in either direction, makes the Sbyke the nimblest scooter yet—one that can purportedly execute tight four-foot turns.