Different gears and ranges of gears are appropriate for different people and styles of cycling. Multi-speed bicycles allow gear selection to suit the circumstances: a cyclist could use a high gear when cycling downhill, a medium gear when cycling on a flat road, and a low gear when cycling uphill. In a lower gear every turn of the pedals leads to fewer rotations of the rear wheel. This allows the energy required to move the same distance to be distributed over more pedal turns, reducing fatigue when riding uphill, with a heavy load, or against strong winds. A higher gear allows a cyclist to make fewer pedal turns to maintain a given speed, but with more effort per turn of the pedals.
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.
The word bicycle first appeared in English print in The Daily News in 1868, to describe "Bysicles and trysicles" on the "Champs Elysées and Bois de Boulogne".[11] The word was first used in 1847 in a French publication to describe an unidentified two-wheeled vehicle, possibly a carriage.[11] The design of the bicycle was an advance on the velocipede, although the words were used with some degree of overlap for a time.[11][12]
Several bills have been sponsored to legalize electric bicycles for use on NYS roads, and several have overwhelmingly passed at the committee level, but none of these initiatives has been able to be heard and then passed in the New York State Senate, until 2015. The latest bill S3997, "An act to amend the vehicle and traffic law, in relation to the definition of electric assisted bicycle. Clarifying the vehicle and traffic law to define electric assisted bicycles; establish that electric assisted bicycles, as defined, are bicycles, not motor vehicles; and establish safety and operational criteria for their use." has passed in the Senate for the first time ever in 2015.[116] The related Assembly bill A233 was not brought to a vote in the assembly even though it had passed with little issue in prior years.[117]

And let’s not forget the economic advantages of owning an e-bike. The annual cost of running a new family car is, on average, about $9,000 per year. Running an electric bike costs around $400 per year. And while filling a gas tank costs around $30, recharging an electric bike battery costs only about 50 cents. A tank of gas may get you further, but not 60 times further!
There are individuals who claim to have lost considerable amounts of weight by using an electric bike.[62] A recent prospective cohort study however found that people using e-bikes have a higher BMI.[63] By making the biking terrain less of an issue, people who wouldn't otherwise consider biking can use the electric assistance when needed and otherwise pedal as they are able.[64] This means people of lower fitness levels or who haven't cycled in many years can start enjoying the many health benefits E-bikes have to offer. [1]
Class 1 makes great inroads to establish set boundaries for off road/natural surface trail access for eMountain bikes. There is fierce resistance from some mountain biking purists to allow ebikes on trails. BPSA and IMBA have done good work to justify the impact of class 1 ebikes on natural surface trails, and eliminate the wear-n-tear argument, though IMBA members are not 100% on board.
Like most electric bikes, the Rad Wagon is also fairly heavy, weighing 72 pounds. The last drawback is that it comes in only one frame size (which I imagine helps to keep costs lower) that fits rider heights between 5 foot 2 inches and 6 foot 2 inches. My 6 foot 4 husband, however, can ride the bike just fine, so there’s some wiggle room to this range.
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!
Photo: This typical electric bicycle, a Sanyo Eneloop (now discontinued), had a range of about 30–55 km (17–35 miles) and a top speed of around 24 km/h (15 mph). Note the 250-watt hub motor on the front wheel and the 5.7Ah lithium-ion battery pack (black, marked "Sanyo," just in front of the back wheel). Picture by kind permission and courtesy of Richard Masoner, originally published on Flickr under a Creative Commons (CC BY-SA 2.0) licence.
Under the Guide Section of EBR, Court has written a full article, dedicated to the new classification approach, which was initiated by the BPSA (Bicycle Product Suppliers Association), supported by PeopleForBikes, and then Calbikes. The initiative was meant to be pro-active with ebike legislation, to establish self-imposed, measurable, distinct classes of electric bikes before states start hearing about anecdotal problems and potentially overreact to the technology with wide sweeping limitations.
However, Emu sells a little foldable number if that's your bag. The Emu Crossbar is for  town commuters that require a sweet ride that's backed up by solid Shimano Nexus hub gears and Tektro brakes, which are adequate if not the best on the market. Riding is smooth and easy, with the crank moving sensor doing its best to iron out any gaps in power delivery.

However, each country is free to allow faster s-pedelecs if they go through collective or individual type approval. Typically, an S-Pedelec can be associated with "mofas" or "mopeds" or "light scooters". Germany has such a solution: S-pedelecs have max. 500W motors, max 45km/h, max 300% support, can drive up to 20Km/h without pedalling, plus other constraints regarding security, and are associated with Mopeds. In the City you can't use bicycles paths, but you can in the country side.

E-bikes are classified in three different types: Class 1 and Class 3 bikes are powered proportionally to the “input” a rider gives via pedaling. “It feels natural, and you’re still riding a bike, so all your reflexes, skill and comfort you’ve developed over years of riding bikes apply immediately,” says Fritz Rice, sales manager of Gregg’s Cycles, near Greenlake.
Ebike definition in Colorado follows the HR 727 National Law: 20 mph (30 km/h) e-power and 750 W (1 hp) max, 2 or 3 wheels, pedals that work. Legal low-powered ebikes are allowed on roads and bike lanes, and prohibited from using their motors on bike and pedestrian paths, unless overridden by local ordinance. The city of Boulder is the first to have done so, banning ebikes over 400W from bike lanes. Bicycles and Ebikes are disallowed on certain high speed highways and all Interstates unless signed as "Allowed" in certain rural Interstate stretches where the Interstate is the ONLY means of travel.[83]
During the course of its evolution, the Specialized Levo has helped shape the world of eMTBing. When it was introduced, it set the benchmark in riding dynamics and integration. Now Specialized has completely redesigned the bike and put it on 29″ wheels. The integration has been improved yet again, the battery capacity has been increased and the handling has been refined. We were thrilled with our first test ride. Anyone looking for a new bike next year for maximum trail performance should definitely take a closer look at the new Levo! We’re already looking forward to our big group test of the best bikes of 2019 early next year. 

There's much less of a sensation of the Electrified S2 'fighting back' once you hit 15.5mph, as well. That's helped by the automatic 2-speed gear box, although this does take some getting used to. Because its cogs are very different sizes you can end up with all sorts of cadence problems as it auto-shifts from high back to low. With practice you can avoid this, or of course you could in theory fit a second cog that's closer in size to the first.

In Norway, e-bikes are classified as ordinary bicycles, according to the Vehicle Regulation (kjøretøyforskriften) § 4-1, 5g. Hence, e-bikes are not registered in the Vehicle Registry, and there is no demand for a license to drive them. Still, there are constraints on the bicycle construction. The maximum nominal motor power output can be no more than 250 watts and the maximum performance speed of the vehicle when the engine is running is 25 km per hour (15 mph).[40] A function that reduces motor power when vehicle speed exceeds 25 km per hour is mandatory. However, if the motor is not running, the e-bike, or any other bike, answer only to the constraints of the ordinary speed limits.

EU: EN15194 (EPAC – Electrically Power Assisted Cycles) defines the use pedal-assisted less than 25k/h bikes: "Cycles with pedal assistance which are equipped with an auxiliary electric motor having a maximum continuous rated power of 0.25 kW, of which the output is progressively reduced and finally cut off as the vehicle reaches a speed of 25 km/h or if the cyclist stops pedaling.” 

{HIGH-QUALITY MATERIAL & AFFORDABLE PRICE} :The electric bikes adopts High-strength Carbon Steel Frame, the front fork is made of High-strength Carbon Steel and packed with premium comfort shock absorption.Affordable Direct to Consumer Pricing (Sell directly from factory),Why are our bikes often less than half the price of comparable bikes on the market? Because we sell direct to you, the consumer.We ensuring you're always getting the best deal on your electric bike
Bicycles helped create, or enhance, new kinds of businesses, such as bicycle messengers,[92] traveling seamstresses,[93] riding academies,[94] and racing rinks.[95][94] Their board tracks were later adapted to early motorcycle and automobile racing. There were a variety of new inventions, such as spoke tighteners,[96] and specialized lights,[91][96] socks and shoes,[97] and even cameras, such as the Eastman Company's Poco.[98] Probably the best known and most widely used of these inventions, adopted well beyond cycling, is Charles Bennett's Bike Web, which came to be called the jock strap.[99]
In addition, we have a new lineup of torque sensors from NCTE to replace the long out-of-stock THUN devices. This restores the option for a true transducer that measures the actual spindle torsion. They provide an accurate human watts readout, and unlike other sensors they can be used in mid-drive setups where the motor is driving the right side chain.
The oldest patent for an electric bike I've been able to find at the US Patent and Trademark Office is this one, by Ogden Bolton, Jr. of Canton Ohio, which was filed in September 1895 and granted three months later. You can see from these original diagrams that it bears an amazingly close resemblance to modern electric bikes. In the general picture on the left, you can see there's a hub motor on the rear wheel (blue), a battery suspended from the frame (red), and a simple handlebar control to make the thing stop and go. In the more detailed cutaway of the hub motor on the right, you can see there's a six-pole magnet in the center (orange) bolted to the frame and an armature (made from coiled wire, yellow) that rotates around it when the current is switched on. It's quite a hefty motor even by modern standards; Ogdon mentions "a heavy current at low voltage—for instance, to carry one hundred amperes at ten volts." So that's 1000 watts, which is about twice the power of a typical modern bike hub motor.
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.
Choose a 36- or 48-volt battery with a capacity of 10Ah or 20Ah. Choose a battery designed for use on an electric bicycle, as it will come with a charger and be much easier to install. Make sure the voltage and capacity of the battery you choose is compatible with the conversion kit you purchased. The higher the voltage of your bike's battery, the more powerful your bike will be. When building an electric bike, choose a 36- or 48-volt battery to allow for speed and comfort.[5]
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]
(ii) a vehicle equipped with two or three wheels, foot pedals to permit muscular propulsion, and an independent power source providing a maximum of 2 brake horsepower. If a combustion engine is used, the maximum piston or rotor displacement may not exceed 3.05 cubic inches, 50 centimeters, regardless of the number of chambers in the power source. The power source may not be capable of propelling the device, unassisted, at a speed exceeding 30 miles an hour, 48.28 kilometers an hour, on a level surface. The device must be equipped with a power drive system that functions directly or automatically only and does not require clutching or shifting by the operator after the drive system is engaged.
"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.[58] 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[0] on a highway that is used primarily by motor vehicles. The department or a local authority may prohibit the use of an electric bicycle[0] on a highway used primarily by pedestrians.
Available products (motors, senors, batteries, control systems. etc.) change fast since the e-bike market shows a strong growth. In principle, get a rear motor if you want a lot of raw power and acceleration (e.g. for a 500W motor). Middle motors are more energy efficient and less subject to problems (e.g. overheating). Middle motors usually are combined with integrated rear hub gears, and rear motors with derailleurs. Both have advantages and disadvantages. E.g. the former require less maintenance, are easy to use in go-and-stop traffic, but require taking off weight on pedals when shifting. Therefore the latter (derailleurs) are better for speedy overland and hills cycling.
Despite the illegal status in the state of New York, enforcement of this law varies at the local level. New York City enforces the bike ban with fines and vehicle confiscation for throttle activated electric bikes.[113] However, Mayor Bill de Blasio has recently changed the city's official policy to legalize pedal-assist electric bikes that have a maximum speed limited to 20 mph. [114] Contrarily, Tompkins County supports electric bike usage, even providing grant money to fund electric bike share/rental projects.[115]
The other motor is the G311, a front equivalent to the wonderfully silent G310 rear motors we introduced late last year. This motor will be replacing the G01 hub for our front mini geared kits. It's a tad lighter (2.3kg), much quieter (spiral gears!), but still has the features from the G01 that we loved. That means a side cable exit, ISO disk rotor compatibility, and 10mm round axle.
Not all e-bikes take the form of conventional push-bikes with an incorporated motor, such as the Cytronex bicycles which use a small battery disguised as a water bottle.[44][45] Some are designed to take the appearance of low capacity motorcycles, but smaller in size and consisting of an electric motor rather than a petrol engine. For example, the Sakura e-bike incorporates a 200 W motor found on standard e-bikes, but also includes plastic cladding, front and rear lights, and a speedometer. It is styled as a modern moped, and is often mistaken for one.[citation needed]
The second type of electric bike is a much smaller, often foldable unit designed for convenient urban (or suburban) commuting and for easy storage in minimal space. These compact electric bikes are perfect for trips of a few miles, and many are small and lightweight enough to be carried onto trains or buses, allowing their rider to make use of multiple types of transportation in a single trip, and to store their bike in a closet or even under a desk at work, at school, or at home.

Tires vary enormously depending on their intended purpose. Road bicycles use tires 18 to 25 millimeters wide, most often completely smooth, or slick, and inflated to high pressure in order to roll fast on smooth surfaces. Off-road tires are usually between 38 and 64 mm (1.5 and 2.5 in) wide, and have treads for gripping in muddy conditions or metal studs for ice.

In cities where bicycles are not integrated into the public transportation system, commuters often use bicycles as elements of a mixed-mode commute, where the bike is used to travel to and from train stations or other forms of rapid transit. Some students who commute several miles drive a car from home to a campus parking lot, then ride a bicycle to class. Folding bicycles are useful in these scenarios, as they are less cumbersome when carried aboard. Los Angeles removed a small amount of seating on some trains to make more room for bicycles and wheel chairs.[65]

"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.[58] 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[0] on a highway that is used primarily by motor vehicles. The department or a local authority may prohibit the use of an electric bicycle[0] on a highway used primarily by pedestrians.

If you're taking your bike inside, consider one that folds up. The Cyclotricity Wallet has a motor in the front wheel, which takes you up to speed either by assisting your pedalling, or you can sit back and use the throttle by itself. Its folding design makes it slightly easier to get in and out of a building, but its hefty weight means you still won't find it easy to carry onto public transport.

Bicycle includes all vehicles propelled by the person riding the same by foot or hand power or a helper motor; and (3) "helper motor" means a motor having a capacity of less than fifty cubic centimeters piston displacement, rated not more than two brake horsepower, capable of a maximum speed of no more than thirty miles per hour and equipped with automatic transmission. Local jurisdictions can pass law at variance with the state law.
The federal Consumer Product Safety Act defines a "low speed electric bicycle" as a two or three wheeled vehicle with fully operable pedals, a top speed when powered solely by the motor under 20 mph (32 km/h) and an electric motor that produces less than 750 W (1.01 hp). The Act authorizes the Consumer Product Safety Commission to protect people who ride low-speed electric vehicles by issuing necessary safety regulations.[63] The rules for e-bikes on public roads, sidewalks, and pathways are under state jurisdiction, and vary.

No person may drive either a two-wheeled or a three-wheeled motorcycle, or a motor-driven cycle unless such person has a valid driver's license specially endorsed by the director to enable the holder to drive such vehicles. No driver's license is required for operation of an electric-assisted bicycle if the operator is at least sixteen years of age. Persons under sixteen years of age may not operate an electric-assisted bicycle. Persons operating electric-assisted bicycles shall comply with all laws and regulations related to the use of bicycle helmets. Electric-assisted bicycles and motorized foot scooters may have access to highways of the state to the same extent as bicycles. Electric-assisted bicycles and motorized foot scooters may be operated on a multipurpose trail or bicycle lane, but local jurisdictions may restrict or otherwise limit the access of electric-assisted bicycles and motorized foot scooters, and state agencies may regulate the use of motorized foot scooters on facilities and properties under their jurisdiction and control.

In conformance with legislation adopted by the U.S. Congress defining this category of electric-power bicycle (15 U.S.C. 2085(b)), CPSC rules stipulate that low speed electric bicycles[64] (to include two- and three-wheel vehicles) are exempt from classification as motor vehicles providing they have fully operable pedals, an electric motor of less than 750W (1 hp), and a top motor-powered speed of less than 20 miles per hour (32 km/h) when operated by a rider weighing 170 pounds.[65] An electric bike remaining within these specifications is subject to the CPSC consumer product regulations for a bicycle. Commercially manufactured e-bikes exceeding these power and speed limits are regulated by the federal DOT and NHTSA as motor vehicles, and must meet additional safety requirements. The legislation enacting this amendment to the CPSC is also known as HR 727.[66] The text of HR 727 includes the statement: "This section shall supersede any State law or requirement with respect to low-speed electric bicycles to the extent that such State law or requirement is more stringent than the Federal law or requirements." (Note that this refers to consumer product regulations enacted under the Consumer Product Safety Act. Preemption of more stringent state consumer product regulations does not limit State authority to regulate the use of electric bicycles, or bicycles in general, under state vehicle codes.)
Electric Bicycles are defined by the California Vehicle Code [32][33]. In summary, electric bicycles are to be operated like conventional bicycles in California. There are several exceptions to this. A person must be at least 16 years old, and anyone riding an electric bicycle must wear a bicycle helmet. The e-bikes must have an electric motor that has a power output less than 1,000 watts, is incapable of propelling the device at a speed of more than 20 miles per hour on level ground, is incapable of further increasing the speed of the device when human power is used to propel the motorized bicycle faster than 20 miles per hour, operates in a manner so that the electric motor is disengaged or ceases to function when the brakes are applied, or operates in a manner such that the motor is engaged through a switch or mechanism that, when released, will cause the electric motor to disengage or cease to function.

Vehicles with an electric power and power of less than 300W are classified as "not a motor vehicle". Such electric bicycles must comply with the same rules as bicycles. You must wear a helmet even on a scooter or bike under 300W. If the power is over 300W or a combustion engine is used it is a "low powered vehicle" and the moped rules apply. Specifically, a drivers license and registration are required.

On October 22, 2014 PA house bill 573 passed into law, which is Act 154, which changes the definition of "pedalcycle" (bicycle) in the PA state vehicle code. "Pedalcycle" is now defined as a vehicle propelled solely by human-powered pedals or a "pedalcycle" (bicycle) with electric assist( a vehicle weighing not more than 100 pounds with two or three wheels more than 11 inches in diameter, manufactured or assembled with an electric motor rated no more than 750 watts and equipped with operational pedals and travels at speeds less than 20 mph). This bill allows the usage of pedal assisted bicycles in PA that follow the adopted state guidelines.