Are you considering an electric bike?  Well here is the what a lot of people are talking about the Copehagen Wheel.  This wheel can replace the back wheel and immediately convert your bicycle into an electric bicycle.  The range is up to 30 miles and controllable via your smart phone.  It can assist you to travel up to 25 mph.   It’s not cheap running around $1500 alone or $2000 included on a bicycle.

 

 

Source: The Copenhagen Wheel | Superpedestrian