RevoPower
 The RevoPower is a motorized wheel concept the idea being the conversion of a pedal-powered bicycle into a motorcycle. It was invented by Denver Colorado based RevoPower Inc.The RevoPower concept is a wheel with a two-stroke engine inside it which allows the bike to which it is attached to travel up to 20 miles per hour (32 km/h) at over 100 miles per US gallon (2.4 L/100 km; 120 mpg-imp).