Not for the balance-challenged

Picture a unicycle without a frame or saddle, and you have the Solowheel. To ride it, you stand on footboards that fold out from the wheel and straddle the wheel. Lean forward, and the wheel engages a battery-powered electric motor that can send it – and hopefully its rider – zooming along at 10 miles per hour. The wheel has a gyroscope that helps keep the rider upright.

Because of the rechargeable battery, which has a 15- to 20-mile range, the Solowheel weighs 26 pounds. That’s as much as a folding bike, but the Solowheel is more compact. It’s sold by Inventist LLC for $1,800.