Federal law in the United States states that an electric bicycle must have a top speed under 20 mph and a motor which produces less than 750 watts/1 hp. They are not considered motor vehicles by the federal government and are subject to the same consumer safety laws as unassisted bicycles. Their legality on public roads is under state jurisdiction, and varies. See the main Electric bicycle laws article for details on the law in individual states.
After you decide which style of e-bike you want, consider the class. In the U.S., there are three classes defined by the type of assist and how fast the motor will propel you. Most electric bikes sold are class 1 or 3. Class 1 bikes have a motor (max 750w) that assists while you’re pedaling, up to 20 mph. Class 3, also known as “speed pedelec,” can also have up to a 750w motor, but it can assist you up to 28 mph. Both are allowed in most states and cities without requiring a license. Class 2 models have throttles that don’t require the rider to pedal in order to get a boost. They’re allowed on most streets, bike lanes, and paths, but are less popular than the other classes and not covered much here (because not only do we still love to pedal, we also prefer the greater distances that pedal-assist bikes can cover).
My homeowners (State Farm) covers bikes , but assumes $500 per bike. They will add the bikes as personal property, but the premium is excessive (about $300/year per bike, and we have four bikes). I did increase our personal umbrella liability coverage, and it covers us if family members any sort of accident on our e-bikes that injures us or others or others' property, though only covers $500 each for our own bikes (under the homeowners coverage). It was not very expensive to increase the umbrella policy (as it resulted also in a reduced rate on our car insurance).
The frame of an electric bike also has to be slightly different. The main part of the frame (the bit that supports your weight) is usually made from lightweight aluminum alloy: the lighter the frame, the lighter the weight of the bike overall, and the further it can travel before you need to recharge the batteries. The spokes on the wheel also have to be stronger than the thin spokes on a traditional bicycle. That's because the electric motor in the hub spins the wheel with a lot of turning force (known as torque) and, if the spokes were ordinary lightweight ones, they could bend or buckle.
Controllers for brushless motors: E-bikes require high initial torque and therefore models that use brushless motors typically have Hall sensor commutation for speed and angle measurement. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. The controllers generally allow input by means of potentiometer or Hall Effect twist grip (or thumb-operated lever throttle), closed-loop speed control for precise speed regulation, protection logic for over-voltage, over-current and thermal protection. Bikes with a pedal assist function typically have a disc on the crank shaft featuring a ring of magnets coupled with a Hall sensor giving rise to a series of pulses, the frequency of which is proportional to pedaling speed. The controller uses pulse width modulation to regulate the power to the motor. Sometimes support is provided for regenerative braking but infrequent braking and the low mass of bicycles limits recovered energy. An implementation is described in an application note for a 200 W, 24 V Brushless DC (BLDC) motor.
On the road, it takes only a few turns of the pedals to activate the Vado’s motor and get it up to speed. In Turbo mode — the bike’s highest level of pedal-assist — the Vado reaches speeds of up to 28 miles per hour, after which the electric drive system automatically shuts off to conserve power (and abide by local law). A built-in LED readout on the handlebars allows riders to monitor battery life, check current speed, and track calories burned while also being able to glance at distance traveled. The Turbo Vado Mission Control app (iOS/Android) also connects to the bike via Bluetooth and allows riders to further tune their ride and adjust the bike’s settings.
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.
Photo: Could solar power be the future of electric bicycles? The large solar panel mounted over the back wheel of this experimental bike powers an electric motor connected by a chain drive to the back wheel, helping the rider when he doesn't feel like pedaling. Using clean, green solar power would remove the problem of having to charge electric bikes with electricity generated from fossil fuels—and help to extend their range significantly. Photo by Warren Gretz courtesy of US DOE/NREL.
Speed Pedelec ebikes – A new classification of bikes called ‘Speed Pedelecs’ have emerged which technically meet the bicycle definition for a 20 mph ebike. These ebikes are designed to max out at 28 mph. Pedelecs are pedal activated vs throttle activated. The weasel words within the definition says, “20mph on motor alone”. Thus, a person who adds their leg power to the motor assist and happens to cruise at 28mph is NOT doing it by motor alone, and therefore the bike is considered to be compliant with the Federal Law. If the rider stops pedaling, the speed pedelec cannot maintain speed. Speed Pedelecs are becoming more popular in Europe and America, which means more models are being offered.
In some countries mixed systems, i.e. pedaling and/or using a throttle is legal. In EU countries and Switzerland this is not the case. I.e. you can buy an electric scooter, but this is not considered to be an e-bike in the moped / light scooter category. That kind of hack is probably more difficult, unless the original design has been modified to fit with (s)Pedelec specs. E.g. The Ezee models are of that kind and modifications to revert to the original does not seem to be too difficult...
Parliament has decided to approve the speed pedelec – a type of super electric bike that can reach speeds of up to 45 km/hour – for riding on cycle paths. Danish Parliament has decided that as of July 1 2018 those operating the super bikes only need to have turned 15 and wear a helmet, while the licence and number-plate demands will no longer be in play. 
"Bicycles" and "Electric Bicycles" are legally defined in the Texas Transportation Code Chapter 551., titled "Operation of Bicycles, Mopeds, and Play Vehicles" in Subchapter A, B, C, and D. The following definition of electric bicycle was passed by the Texas legislature in 2001. "Electric bicycle" means a bicycle that is designed to be propelled by an electric motor, exclusively or in combination with the application of human power, cannot attain a speed of more than 20 miles per hour without the application of human power; and does not exceed a weight of 100 pounds. The department or a local authority may not prohibit the use of an electric bicycle on a highway that is used primarily by motor vehicles. The department or a local authority may prohibit the use of an electric bicycle on a highway used primarily by pedestrians.
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.
Most electric bicycles can be classified as zero-emissions vehicles, as they emit no combustion byproducts. The environmental effects of electricity generation and power distribution and of manufacturing and disposing of (limited life) high storage density batteries must be taken into account. Even with these issues considered, electric bicycles will have significantly lower environmental impact than conventional automobiles, and are generally seen as environmentally desirable in an urban environment. The small size of the battery pack on an electric bicycle, relative to the larger pack used in an electric car, makes ebikes very good candidates for charging via solar power or other renewable energy resources. Sanyo capitalized on this benefit when it set up "solar parking lots," in which ebike riders can charge their vehicles while parked under photovoltaic panels.
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.
Nebraska defines a Moped as "a bicycle with fully operative pedals for propulsion by human power, an automatic transmission, and a motor with a cylinder capacity not exceeding fifty cubic centimeters which produces no more than two brake horsepower and is capable of propelling the bicycle at a maximum design speed of no more than thirty miles per hour on level ground."
Electric bicycles are considered as "bicycles" under Montana law as the law defines bicycles in a two part definition where the first part of the definition describes a conventional bicycle propelled solely by human power and the second part of the definition describes a bicycle equipped with an independent power source for propulsion in addition to foot pedals to permit muscular propulsion. (Montana Code 61-8-102).
A human traveling on a bicycle at low to medium speeds of around 16–24 km/h (10–15 mph) uses only the power required to walk. Air drag, which is proportional to the square of speed, requires dramatically higher power outputs as speeds increase. If the rider is sitting upright, the rider's body creates about 75% of the total drag of the bicycle/rider combination. Drag can be reduced by seating the rider in a more aerodynamically streamlined position. Drag can also be reduced by covering the bicycle with an aerodynamic fairing. The fastest recorded unpaced speed on a flat surface is 144.18 km/h (89.59 mph)
At just 36V and 5.2 Ah, the battery is not designed for long distance travel. GOTRAX claims the Shift S1 has a range of up to 15 miles (25 km), though that’s only with a lower pedal assist level. If you’re going full throttle, 10 miles (15 km) is a better estimate. But with a battery this small, you could easily charge it at your desk or in the corner of the classroom – lengthening your effective range.
A new European product safety standard EN 15194 will be published in 2009. EN 15194 contains several new requirements for ebikes to be sold in European Union and European Economic Area, including weight and voltage limitations. EN 15194 also defines a specific name for EU approved electrically-assisted cycles, EPAC - "Electrically Pedal Assisted Cycle".
The Bosch Performance CX is still one of the most popular motors on the market. It’s synonymous with reliability, but it’s getting on in years. The newly presented Active Line looks like a glimpse into Bosch’s future: it is more compact, lighter, has less internal resistance, and uses a large chainring. It can only be a matter of time before Bosch releases a new performance motor.
Riding position: You also may wish to check out an e-bike’s riding position before investing in it. For short trips, the riding position might not make much difference, but for long journeys, the upright "Dutch" style with pulled-back handlebars is very comfortable – particularly for tall riders. The same goes for mountain bike styles, though these bikes are not often designed to actually go off-road.
The bicycle is extraordinarily efficient in both biological and mechanical terms. The bicycle is the most efficient human-powered means of transportation in terms of energy a person must expend to travel a given distance. From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels, although the use of gearing mechanisms may reduce this by 10–15%. In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also an efficient means of cargo transportation.
A lot has happened since we founded the very first eMTB specific magazine in 2013. In the beginning, manufacturers simply mounted electric motors on regular mountain bikes, more or more often than not, rather less successfully. Last year a lot of brands focused on the topic of battery integration. There are some exciting new trends and developments headed our way next season, which we take a closer look at below.
These small complaints prove that the Rad Wagon isn’t perfect. But its overwhelmingly positive qualities clearly outweigh the drawbacks. The Rad Wagon handled beautifully on city streets, accelerating with ease and maintaining a charge for extended range. Rad Power bikes also offers an array of helpful accessories—think racks, baskets, panniers, and platforms—that make the bike nearly as convenient as a car. Time and time again I passed cars stuck in traffic on their daily commute and couldn’t help but wondering: Why don’t more people switch from cars to an e-bike?
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.
Since 2000, Canada's Motor Vehicle Safety Regulations (MVSR) have defined Power Assisted bicycles (PABs) as a separate category, and which require no license to operate. PABs are currently defined as a two- or three-wheeled bicycle equipped with handlebars and operable pedals, an attached electric motor of 500W or less, and a maximum speed capability of 32 km/h from the motor over level ground. Other requirements include a permanently affixed label from the manufacturer in a conspicuous location stating the vehicle is a power-assisted bicycle under the statutory requirements in force at the time of manufacture. All power-assisted bicycles must utilize an electric motor for assisted propulsion.
It appears Tennessee has not passed any legislation that applies to electric bicycles. Some people think the laws pertaining to a Motorized Bicycle should be used for an electric bicycle. However, a Motorized bicycle would be a gasoline powered device per state law as it is defined as "means a vehicle with two (2) or three (3) wheels, an automatic transmission, and a motor with a cylinder capacity not exceeding fifty cubic centimeters (50cc) which produces no more than two (2) brake horsepower and is capable of propelling the vehicle at a maximum design speed of no more than thirty miles per hour (30 mph) on level ground." 
Step-throughs were popular partly for practical reasons and partly for social mores of the day. For most of the history of bicycles' popularity women have worn long skirts, and the lower frame accommodated these better than the top-tube. Furthermore, it was considered "unladylike" for women to open their legs to mount and dismount—in more conservative times women who rode bicycles at all were vilified as immoral or immodest. These practices were akin to the older practice of riding horse sidesaddle.
Fast and fun on the trail, the SDURO HardNine handles rough terrain with ease, while its large tires roll over most obstacles without missing a beat. The pedal assist makes for quick, energy-saving climbing and the bike descends surprisingly well, too. Its front suspension provides a nice level of cushion on bumpy trails and while we missed having a full-suspension on this model, that would have added additional weight and costs.
In the year 1885, a British man named J.K. Stanley introduced what can fairly be described as the first modern bicycle. His Rover bike had wheels of equal size in the front and back and used a chain connecting the pedals and the rear wheel as a propulsion system. It was often marketed as a safety bike in contrast with the unstable Penny Farthing, and was a smashing success. The company went on to develop motorcycles and automobiles, remaining in business until the year 2005.
The company was founded in 2009 by Tora Harris who graduated from Princeton University with a degree in Mechanical and Aerospace Engineering. While at Princeton, Harris ran track and became a 2-time winner of the NCAA Championship in the High Jump and set several Ivy League track records in the process. Harris went on to win 2 USA National Outdoor Championship Titles and competed in the 2004 Athens Olympic Games.
Biking is awesome, but biking uphill is not. Commuting by bike is environmentally friendly, fun and good for your health, but presenting your sweaty self to your office coworkers in not fun at all. Fortunately, there is a solution! Electric bicycles offer the same great benefits as traditional bicycles including cost savings, health improving, plus some additional advantages like efficiency in climbing hills, less stress on knees and joints, which is convenient for people of all ages and health.