Electric downhill mountain bikes have recently been introduced, allowing one to easily traverse hills and eliminating the need for a separate vehicle to ferry them to the top. Through battery powered bicycles are a recent phenomenon, power assisted bikes have been with us for over a hundred years, the first one being developed in 1895. They ran on gasoline, but it was not until the invention of modern torque sensors, power controllers , and battery technology in the 1990's that today's power assisted electric bicycles became possible. In China, an industry which began in its infancy in the late 1990's has exploded to the point where ten years later, electric bikes outnumber automobiles four to one.
The preferred battery technology today is lithium-ion, which is able to deliver power from a more compact package than its predecessor, the lead acid battery. This brings the weight of some electric downhill mountain bikes down to 50 pounds. Lithium ion batteries typically give 25 miles per charge. The battery is usually stowed on a platform behind the rear wheel, but can also be hidden in a backpack or mounted onto the frame.
Electric bikes running on lead acid batteries start at $ 350, but full suspension downhill mountain bikes running on lithium-ion batteries can run over $ 2000. Most are rear wheel drive, but an all wheel drive is available for about $ 4000. They are power assisted, meaning power is applied in response to the rider's pedaling force, with pedaling being the main driver. Conversion kits to retrofit existing bikes are available.
Some electric downhill mountain bikes can achieve speeds of 40mph. The top speed determinates whether it is street legal, which varies by local or regional jurisdiction. Licensing requirements vary as well. In the United States, if their top speed is less than 20mph, they are considered bicycles.
Source by Mac Craven