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.
The legal definition/description of an electric bicycle is most closely described in the code as a "motorized scooter" in that it is powered by an electric motor and/or human power [45]. It may be also be described as a "Motorized bicycle". However, that description does not include electric powered motor specifically. And it appears that the legal definition "Motorized Bicycle" and "Motorized Scooter" are in conflict. Motorized bicycle is a pedal bicycle which has a helper motor, or a non-pedal bicycle which has a motor, with a cylinder capacity not exceeding fifty cubic centimeters, an automatic transmission, and which is capable of a maximum speed of no more than thirty miles per hour. A motorized bicycle shall not be operated upon any way, as defined in section one within the commonwealth by any person under sixteen years of age, nor at a speed in excess of twenty-five miles per hour. A motorized bicycle shall not be operated on any way by any person not possessing a valid driver’s license or learner’s permit. Every person operating a motorized bicycle upon a way shall have the right to use all public ways in the commonwealth except limited access or express state highways where signs specifically prohibiting bicycles have been posted, and shall be subject to the traffic laws and regulations of the commonwealth and the regulations contained in this section, except that the motorized bicycle operator may keep to the right when passing a motor vehicle which is moving in the travel lane of the way, and the motorized bicycle operator shall signal by either hand his intention to stop or turn. Motorized bicycles may be operated on bicycle lanes adjacent to the various ways, but shall be excluded from off-street recreational bicycle paths. Every person operating a motorized bicycle or riding as a passenger on a motorized bicycle shall wear protective headgear conforming with such minimum standards of construction and performance as the registrar may prescribe, and no person operating a motorized bicycle shall permit any other person to ride a passenger on such motorized bicycle unless such passenger is wearing such protective headgear.

E-bikes are typically offered in 24V, 36V and 48V configurations. Higher voltage generally means higher top speed – but that may not always be the case. Since the efficiency of a motor and drive system can have an effect on power and speed, a 24V setup could have the same top speed as a 36V setup. Generally you can expect 15-18 mph on a 24v setup, 16-20 mph on a 36V setup and 24-28 mph on a 48V setup. Although it far exceeds Federal laws, some conversion kits can even be run at 72V for speeds of 35+ mph! However, this puts significant stress on bicycle components. Consider that even the fastest athletes only travel 17-18 mph on a conventional bicycle, so 20 mph feels very fast to most riders. Anything over this speed can be unsafe and exceeds law regulations.
However, laws and terminology are diverse. Some countries have national regulations but leave the legality of road use for states and provinces to decide. Municipal laws and restrictions add further complications. Systems of classification and nomenclature also vary. Jurisdictions may address "power-assisted bicycle" (Canada) or "power-assisted cycle" (United Kingdom) or "electric pedal-assisted cycles" (European Union) or simply "electric bicycles". Some classify pedelecs as distinct from other bikes using electric power. Thus, the same hardware may be subject to many different classifications and regulations.
Metro is a brand that has been around since 2010, and it is one of the top sellers. That is mostly because their products are solid, good value, with good power and good features. Metro Hybrid is a part of urban electric bikes family, and it is really well set up for the urban and light trail riding. Metro has a diamond frame and 700c (28-inch) wheels with sporty 38mm Schwalbe Marathon tires, so you get real quality tires. A big capacity battery of 624Wh will carry you 20–40 miles, with the top speed of 28 mph with assist,  or 20mph using throttle only. The comfort is decent with adjustable handle bar, as well as suspension seat post and a suspension fork. Overall, this bike offers good value for the price, with outstanding range and power for its class.
The Wavecrest Tidalforce M-750 was based on The original military experimental M-313 model. The M-313/M-750X was the first electric bike to be made and tested by Wavecrest Labs. It is based on a design developed for the Defense Advanced Research Projects Agency (DARPA) that was meant to allow zero-heat long distance troop movements for the United States Marine Corps in Afghanistan. The rear wheel in-hub motor and 36 volt/8ah front-hub battery were mounted onto a standard Montague Bicycles Paratrooper Bicycle frame. The 1000 watt rear hub motor had no set speed restriction, but was limited to about 25-32 (depending on load weight) MPH on a flat course. The distance the bike traveled on a single charge ranged from 15 miles (heavier load with no pedaling) to about 25 miles (vigorous assisted pedaling with less hill climbing).
The Christmas day is coming soon, since I receive the bike, it's about a week, and I am satisfied with it! just as advertised, very powerful and good design. the most important point is that once the battery is FULL CHARGE, how far it can reach up to. I have a funny test, in the normal road(not in the dramatic slope or uphill), it can goes almost 44 miles. That is what I give 5 star for this bike! very powerful with reasonable price!
The Espin is powered by a 350-watt motor that’s rated for trips up to 50 miles (depending on the terrain and assist level). Once depleted, the battery fully charges in roughly five hours. Thankfully, Espin makes it easy to remove the battery, allowing you to quickly recharge it at home or in the office between trips. A backlit LCD control hub displays your basic metrics and battery life while in transit and LED headlights add a touch of light when needed.
I eventually got used to it over time, but at first having both kids behind me made the bike feel like it would sway to or fro perilously. I think it was just too much weight to navigate safely, and would be fine with younger kids that didn’t come close to the 120-pound weight limit for the rear cargo area. Overall I’m still a bit partial to a box-style bike if I’m hauling multiple kids and want to be able to see what they’re doing.
My one complaint is the bike’s weight. This sucker is heavy! The aluminum frame looks light, but the the hub motor (4 pounds) and battery (5 pounds) add up. The bike’s total weight is 39 pounds, which is about average for e-bikes but not something you’d want to lug around all day. “This is not a solution for everybody,” Miller admits. “If you live in a fifth floor walkup this is probably not going to work.”
Some argue, that an ebike should have some kind of front suspension, i.e. be able to cope with potholes at higher speed or off-road conditions. However, in countries with flat roads (e.g. Switzerland, Germany or Holland) you don't need that extra weight for extra price if you stay on roads and/or drive slowly in difficult terrain. Some makes (like the Stromer) let you choose.
An itinerant wordsmith with a broad constellation of interests, Lydia Chipman has turned iconoclasm into a livelihood of sorts. Bearing the scars and stripes of an uncommon diversity of experience -- with the notable exceptions of joining a religious order or becoming an artist -- she still can’t resist the temptation to learn something new. Lydia holds a master of arts in English from Georgia Southern University, and a bachelor of arts cum laude in integrative studies from Clayton College. Her expertise is in the areas of robotics, electronics, toys, and outdoors and computer equipment.
Some argue, that an ebike should have some kind of front suspension, i.e. be able to cope with potholes at higher speed or off-road conditions. However, in countries with flat roads (e.g. Switzerland, Germany or Holland) you don't need that extra weight for extra price if you stay on roads and/or drive slowly in difficult terrain. Some makes (like the Stromer) let you choose.
Electric bikes are a green alternative to driving a vehicle. Studies carried out in several towns and cities show that the average car speed in rush hour traffic can dip as low as 18 to 20 mph. Electric bike speed can be as high as 15 mph. With an electric bike, you can reduce pollution, improve fitness, and still arrive at the same time as your car-bound colleagues.
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 U.S. Consumer Product Safety Act states that electric bicycles and tricycles meeting the definition of low-speed electric bicycles will be considered consumer products. The Consumer Product Safety Commission (CPSC) has regulatory authority to assure, through guidelines and standards, that the public will be protected from unreasonable risks of injury or death associated with the use of electric bicycles.[61][62]

At Volt, when we sell an ebike, we like to keep in touch with our customers. This is not only to find out how their electric bike is performing and if they are happy with it, but also to learn how they use it. Many have impressive stories to tell. We have heard from people using Volt bikes in the most diverse ways and places, from the Scottish Highlands to central London.
It should be noted that the definition as written does not define the power of the motor in Watts as is conventionally done for electric bicycles but rather in brake horsepower. Thus for an electric bicycle, motor kit, or electric bicycle motor that is not rated by the manufacture in brake horsepower but rather in Watts a conversion must be made in the units a conversion which is not given in the code of the law and thus the court will have to consider a factor of conversion that is not directly encoded in the law. Industry standard conversion for Watts to horsepower for electric motors is 1 horsepower = 746 watts.[105] Acceptance of that conversion factor from industry, however, as interpretation of the law is subject to the process of the courts since it is not defined specifically in the law.
Electric-assisted bicycles are treated as human-powered bicycles, while bicycles capable of propulsion by electric power alone face additional registration and regulatory requirements as mopeds. Requirements include electric power generation by a motor that cannot be easily modified, along with a power assist mechanism that operates safely and smoothly. In December 2008, The assist ratio was updated as follow: