Historically, materials used in bicycles have followed a similar pattern as in aircraft, the goal being high strength and low weight. Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. By the 1980s aluminum welding techniques had improved to the point that aluminum tube could safely be used in place of steel. Since then aluminum alloy frames and other components have become popular due to their light weight, and most mid-range bikes are now principally aluminum alloy of some kind.[where?] More expensive bikes use carbon fibre due to its significantly lighter weight and profiling ability, allowing designers to make a bike both stiff and compliant by manipulating the lay-up. Virtually all professional racing bicycles now use carbon fibre frames, as they have the best strength to weight ratio. A typical modern carbon fiber frame can weighs less than 1 kilogram (2.2 lb).
The Tidalforce Electric Bicycle was an electric bicycle manufactured by Wavecrest Labs from 2003 until the company went out of business in 2006. All models of Wavecrest Tidalforce electric bikes have a 36 volt electric hub motor built into the rear wheel hub and a 36 volt battery pack built into the front wheel hub. Wavecrest Labs manufactured three models of Tidalforce bikes: The Wavecrest Tidalforce M-750, the S-750 Traditional hard tail mountain bike and the iO-750 Cruiser. Any of the three bikes with an X suffix denotes that the motor is a 1000 watt motor without a set speed restriction as compared to the speed limited 750 watt version.
In Nova Scotia power-assisted bicycles are classified similarly to standard pedal bicycles. The Nova Scotia Motor Vehicle Act defines a power-assisted bicycle as a bicycle with an electric motor of 500 watts or less, with two wheels (one of which is at least 350 mm) or four wheels (two of which are at least 350mm). PABs are permitted on the road in the province of Nova Scotia as long as you wear an approved bicycle helmet with the chinstrap engaged. They do not have to meet the conditions defined within the Canadian Motor Vehicle Safety Regulations for a motorcycle (they are not classed as "motor vehicles"), but they do have to comply with federal regulations that define Power Assisted Bicycles.
With a chain drive transmission, a chainring attached to a crank drives the chain, which in turn rotates the rear wheel via the rear sprocket(s) (cassette or freewheel). There are four gearing options: two-speed hub gear integrated with chain ring, up to 3 chain rings, up to 11 sprockets, hub gear built into rear wheel (3-speed to 14-speed). The most common options are either a rear hub or multiple chain rings combined with multiple sprockets (other combinations of options are possible but less common).
Another style is the recumbent bicycle. These are inherently more aerodynamic than upright versions, as the rider may lean back onto a support and operate pedals that are on about the same level as the seat. The world's fastest bicycle is a recumbent bicycle but this type was banned from competition in 1934 by the Union Cycliste Internationale.[43]
Louisiana Revised Statute R.S. 32:1(41) defines a motorized bicycle as a pedal bicycle which may be propelled by human power or helper motor, or by both, with a motor rated no more than one and one-half brake horsepower, a cylinder capacity not exceeding fifty cubic centimeters, an automatic transmission, and which produces a maximum design speed of no more than twenty-five miles per hour on a flat surface. Motorized bicycles falling within this definition must be registered and titled under Louisiana law. Additionally, a motorized bicycle operated upon Louisiana roadways or highways by a person fifteen years of age or older and producing more than five horsepower must possess a valid driver's license with a motorcycle endorsement and adhere to laws governing the operation of a motorcycle, including the wearing of approved eye protectors or a windshield and the wearing of a helmet. The statute also states that "Motorized bicycles such as pocket bikes and scooters that do not meet the requirements of this policy shall not be registered."
Both the Stromer and the Stoeckli are very nice looking designs and easy to handle. Reliability for both does not seem to be up to Swiss standards, e.g. some of the 2012 Stöcklis seem to have bad contacts. However, as of 2013, most of these problems should be fixed. The Cube got criticized for its battery/saddle system, but this has probably been fixed in more recent edition and it has less "punch" then the other's since the motor is smaller (324W?). I don't know about the BH Neo Nitro. Given the relatively low price of the BH Nitro, it may be the best buy in this category if you plan to cover smaller distances (the battery is limited to 9Ah, and Spain's industry does need some help ;) Anyhow, all of these models come with a variety of motors and country-specific modifications. E.g. in France, the BH Nitro comes with a 350W motor and is electronically limited to 25km/h, whereas in Switzerland you either can get a 500W - 45 km/h version or a 250W? - 25km/h version.
Bicycles were introduced in the late 19th century in Europe, and by the early 21st century, more than 1 billion were in existence at a given time.[1][2][3] These numbers far exceed the number of cars, both in total and ranked by the number of individual models produced.[4][5][6] They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys, general fitness, military and police applications, courier services, bicycle racing and bicycle stunts.
The Riese & Müller Load Touring HS is billed as “the ultimate minivan of e-bikes,” and it holds up to that claim. With a low center of gravity (aided by the 20-inch front and 26-inch rear wheels), the Load is easy to handle. Tektro hydraulic disc brakes add control, and front and rear suspension provide comfort. The Bosch motor offers an assist up to 275 percent of your effort until you hit 28 mph, when it cuts out. Two 500Wh batteries give you 12 hours or more of range at full power. It’s capable of toting up to 220 pounds of pets, people, and less-animate cargo. R&M also sells a double child seat for kids up to age 6 and a child-seat fastener for your youngest passengers.

In Quebec power-assisted bicycles are often classified similarly to standard pedal bicycles. They do not have to meet the conditions defined within the Canadian Motor Vehicle Safety Regulations (they are not classed as "motor vehicles"), but they do have to comply with federal regulations that define Power Assisted Bicycles. The Quebec Highway Safety Code defines a power-assisted bicycle as a bicycle with an electric motor. PABs are permitted on the road in the province of Quebec.
The federal law will not prohibit a motor vehicle label and additional restrictions given by the state. States will typically define e-mopeds in the 1000W range (1.5 hp) and speeds attainable to 30mph, and include a few requirements such as a helmet, eye protection, and a driver’s license. States may also require title, registration, and insurance for mopeds.
Electric-assisted bicycles, also referred to as "e-bikes," are a subset of bicycles that are equipped with a small attached motor. To be classified as an "electric-assisted bicycle" in Minnesota, the bicycle must have a saddle and operable pedals, two or three wheels, and an electric motor of up to 1,000 watts, as well as meet certain federal motor vehicle safety standards. The motor must disengage during braking and have a maximum speed of 20 miles per hour (whether assisted by human power or not). Minn. Stat. §169.011, subd. 27.
The basic shape and configuration of a typical upright or "safety bicycle", has changed little since the first chain-driven model was developed around 1885.[7][8][9] However, many details have been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for many types of cycling.
The two most common types of hub motors used in electric bicycles are brushed and brushless. Many configurations are available, varying in cost and complexity; direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle using chain drive, belt drive, hub motors or friction drive. BLDC hub motors are a common modern design. The motor is built into the wheel hub itself, and the stator fixed solidly to the axle, and the magnets attached to and rotating with the wheel. The bicycle wheel hub is the motor. The power levels of motors used are influenced by available legal categories and are often, but not always limited to under 750 watts.
Artwork: Hub motors aren't the only way to power electric bicycle wheels. If you've ever watched a mouse scampering around inside an exercise wheel, you might have wondered if you could drive a wheel electrically, in a similar way, with something that pushes against the inside of the rim. A company called GeoOrbital has been developing an ingenious mechanical equivalent that can be used to power conventional bikes—and here's a simplified illustration of how it works. It has a motorized drive roller (red) that presses against the inner rim, powered by a battery pack (orange) that sits snugly inside the wheel. Two guide rollers (blue) mounted on a tensioned framework (green) take the place of the conventional arrangement of spokes. According to GeoOrbital, you can fit one of its wheels to a normal bike in just 60 seconds.

Haibike ships the HardNine with 29-inch tires, 180-millimeter hydraulic disc brakes, a 100-millimeter front suspension fork, and a nine-speed Shimano shifting system. The bike’s LCD readout is affixed to the handlebars and displays the current speed, level of charge, remaining range, and current pedal assist mode. The company says the battery can be completely recharged in just four hours, minimizing downtime between rides. 
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