In a friction drive motor, a small, solid wheel rotates against the side of the tire in order to drive it. The first motorcycles used the same concept, with a motor mounted above the front wheel. The problem is that the drive rubs at the side of the tire. It's inefficient, and it quickly wears the sidewall away. Tires need to be replaced every couple hundred miles. For this reason, you'll seldom see electric bikes with this type of drive anymore.
An electric bicycle, also known as an e-bike, powerbike or booster bike, is a bicycle with an integrated electric motor which can be used for propulsion. Many kinds of e-bikes are available worldwide, from e-bikes that only have a small motor to assist the rider's pedal-power (i.e., pedelecs) to somewhat more powerful e-bikes which tend closer to moped-style functionality: all, however, retain the ability to be pedalled by the rider and are therefore not electric motorcycles.
This bike is named the GSD because with it you can Get Stuff Done. Twenty-inch wheels keep the center of gravity low so heavy payloads—it's rated up to 400lbs—are easy to balance and a short (for a cargo bike) 70-inch wheelbase, similar to a standard single bike, make the GSD easy to maneuver. Designed with the urban commuter in mind, the bike can easily break down to 60 percent of its original size to fit into the back of a car and the rear rack doubles as a stand that allows it to stand upright to minimize space inside tight apartments. Put two child seats on the back and take the family along, or drop the seat and let you kid take the bike out himself—anyone from 4'10" to 6'5" can ride this bike. Last but not least, the GSD gives you the option of adding a second battery to extend your range up to about 150 miles on a single charge.
For many bikes, battery range is more important that total power (because they're all pretty powerful). You want a bike that delivers a range long enough for your rides at the power levels you want. Most e-bikes will have three to five levels of assist kicking in anywhere from 25 percent of you pedal power to 200 percent boost. Consider how fast the battery takes to recharge, especially if you'll be using your bike for long commutes.