There are various kinds and classifications of electric bikes on the market, but the more common type is the Class 1, or pedal assist, bikes which have motor units that are activated by pedaling and are limited to lower speeds. In the US, Class 1 electric bikes, the type tested and reviewed here, are limited to a top speed of 20 mph and their motors are designed with a speed governor to regulate this. These types of e-bikes resemble modern mountain bikes, but they have significant battery packs and small motor units integrated onto and into the frame design. The e-MTB pedal-assist motor is typically built around the bottom bracket and provides varying levels of pedaling "support" directly into the drivetrain while the cranks are turning. Most drive unit systems offer several support settings that provide pedal assistance between 25% and 100% of the user's pedaling input.
Range is a key consideration with e-bikes, and is affected by factors such as motor efficiency, battery capacity, efficiency of the driving electronics, aerodynamics, hills and weight of the bike and rider. Some manufacturers, such as the Canadian BionX or American Vintage Electric Bikes, have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging. This is useful for extending the range and the life of brake pads and wheel rims. There are also experiments using fuel cells. e.g. the PHB. Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS. E-bikes developed in Switzerland in the late 1980s for the Tour de Sol solar vehicle race came with solar charging stations but these were later fixed on roofs and connected so as to feed into the electric mains. The bicycles were then charged from the mains, as is common today. While ebike batteries were produced mainly by bigger companies in past, many small to medium companies have started using innovative new methods for creating more durable batteries. State of the art, custom built automated precision CNC spot welding machines created 18650 battery packs are commonly used among Do-it-yourself ebike makers.
Probably the only readily available, mass-production downhill-specific e-MTBs on the market… well, downhill preferred anyway. Don't be afraid to test the limits on this one! Haibike’s xDuro Downhill’s intention is to assist with the pedal back to the top so riders can self-shuttle, instead of taking chairlifts or vans to the top. If you are Haibike pro rider Sam Pilgrim, you could also use this bike to go upside down over enormous jumps. The e-DH bike is a good idea – who can argue that fewer shuttle buses needed to ferry gravity fiends is a bad thing?
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, while in others, such as China as of 2010, they are replacing fossil fuel-powered mopeds and small motorcycles.