E-bikes use rechargeable batteries and the lighter ones can travel up to 25 to 32 km/h (16 to 20 mph), depending on local laws, while the more high-powered varieties can often do in excess of 45 km/h (28 mph). In some markets, such as Germany as of 2013, they are gaining in popularity and taking some market share away from conventional bicycles,[1] while in others, such as China as of 2010, they are replacing fossil fuel-powered mopeds and small motorcycles.[2][3]

All models of the Turbo Levo use a frame made from M5 aluminum alloy, with the motor and removable battery integrated inside. The frame and fork use 148mm (rear) and 110mm (front) spacing. Specialized 6Fattie Purgatory (front) and Ground Control (rear) 3-inch wide tires are laced to 38mm Roval Traverse rims. Rear stays and pivots are beefed up to handle the additional weight (48.5 lbs) and torque, and bridges are added to the stays, over the non-motorized Stumpjumper. The front fork is a RockShox Yari XC with a 15mm thru-axle. The 135mm rear travel is provided by a custom Fox Float Performance DPS shock with automatic sag adjust. 
Aluminium alloy frames and downtube mounted batteries with integrated motors provide a budget friendly introduction to these motor-assisted bikes, allowing riders who would struggle to keep up to enjoy the stamina of the pros. For those hard hitters, fully integrated battery and motors combine with lightweight alloy and carbon frames to deliver a ride that’ll take on the most demanding trails.
Bottom Line The Specialized Turbo Levo FSR Comp 6Fattie was the most well rounded bike in our test, the winner of our Editor's Choice Award. Commencal's first foray into the e-bike market was worth the wait with a hard charging ride that utilizes their Meta frame design and Shimano's E8000 motor. The HaiBike XDURO AllMtn features a powerful pedal assist motor, but in a less refined package. The Trek Powerfly 7 FS is a good electric mountain bike, but its component specification is holding it back from reaching its potential.
Since the pedal assist doesn’t engage while coasting, climbing is where this bike really shines. We tested the bike on southern California’s fire roads, undulating traverses, and on some very steep, rocky, loose, and technical trails—the kind of stuff even the most skilled and fit riders would normally find themselves hiking up—and on the Turbo Levo we were able to ride all of it, and have a blast doing so. 
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895, Ogden Bolton Jr. was granted U.S. Patent 552,271 for a battery-powered bicycle with "6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel". There were no gears and the motor could draw up to 100 amperes (A) from a 10-volt battery.[5]
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