Power-assist: Also known as pedal-assist bikes, these are the bicycle equivalents of hybrid cars: they're designed to be pedaled quite a lot of the time and electrically powered either when you're tired or when you feel like a bit of electric help (when you're going up hill, for example). Unlike full-power bikes, they don't have hub motors; instead, there's a separate electric motor mounted near the rear wheel and driving it either through the gear sprocket or simply by pressing against the rear tire. Where a hub motor is difficult or impossible to pedal without any power (because you're effectively turning it into a generator), power-assist motors turn easily with little or no resistance when you pedal. That gives power-assist bikes much greater range than hub-motor ones (as much as 80–145km or 50–90 miles).

Gearless (Direct-Drive) Hub Motors – Some conversion kits (and bikes) use gearless, direct-drive motors. On this type of motor, the axle that passes through the center of the motor is actually the axle of the motor itself, with the copper windings fixed to the axle. The magnets are mounted to the outer shell of the hub motor. When electricity is applied to the stator a magnetic field is induced that causes the magnets to move. This in turn makes the whole shell of the motor turn and propels the e-bike forward. Even though corrosion will eventually have an impact, this type of motor should last for years since there’s no gearing and no contact between moving parts. They’re also capable of higher top speeds. But since there’s no gears, they have less torque and it requires more power to get the motor up to speed. Most direct-drive hub motors are 350w-500w and reach speeds of 18-25 mph. But more powerful motors can reach speeds of 35+ mph.
Even the humble bicycle hasn't escaped the clutches of modern technology. A whole herd of new e-bikes with electric motors are taking to our cities' streets. Adding a motor to a standard cycle does ramp up the price significantly, but it takes much of the effort out of cycling, making your commute to the office a sweat-free experience and allowing you to sit back and enjoy your suburban cruise.
A local unit of government having jurisdiction over a road or bikeway (including the Department of Natural Resources in the case of state bike trails) is authorized to restrict e-bike use if: the use is not consistent with the safety or general welfare of others; or the restriction is necessary to meet the terms of any legal agreements concerning the land on which a bikeway has been established.
Bicycle brakes may be rim brakes, in which friction pads are compressed against the wheel rims; hub brakes, where the mechanism is contained within the wheel hub, or disc brakes, where pads act on a rotor attached to the hub. Most road bicycles use rim brakes, but some use disk brakes.[49] Disc brakes are more common for mountain bikes, tandems and recumbent bicycles than on other types of bicycles, due to their increased power, coupled with an increased weight and complexity.[50]
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.
Further innovations increased comfort and ushered in a second bicycle craze, the 1890s Golden Age of Bicycles. In 1888, Scotsman John Boyd Dunlop introduced the first practical pneumatic tire, which soon became universal. Willie Hume demonstrated the supremacy of Dunlop's tyres in 1889, winning the tyre's first-ever races in Ireland and then England.[28][29] Soon after, the rear freewheel was developed, enabling the rider to coast. This refinement led to the 1890s invention[30] of coaster brakes. Dérailleur gears and hand-operated Bowden cable-pull brakes were also developed during these years, but were only slowly adopted by casual riders.
Besides voltage, batteries are rated by amp hours (AH). Although voltage seems to get the most attention, the amp hour rating of the battery is just as important. It is the measure of a battery’s capacity and provides a good indication of the range you can expect from an electric bike. Although lots of factors come into play in determining range (ie: rider weight, terrain, input, efficiency, etc.), a good rule of thumb is range is equal to AH. So under normal conditions, an average rider can expect 10 miles out of a 10AH battery (with no pedaling). With rider input, this number can be dramatically increased, so most 10AH batteries are rated “up to 20 miles” by the manufacturer which assumes pedaling. On pedal-assist bikes (which require pedaling), the range ratings are much higher because the rider is constantly assisting the motor and reducing the current draw.

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.
October 5, 2009 — Ontario is bringing in some new safety requirements for electric bikes. E-bikes, which can reach a speed of 32 kilometres per hour, are allowed to share the road with cars, pedestrians and other traffic throughout the province. The new rules limit the maximum weight of an e-bike to 120 kilograms, require a maximum braking distance of nine metres and prohibit any modifications to the bike's motor that would create speeds greater than 32 kilometres per hour. Also, riders must be at least 16 years of age, wear approved bicycle or motorcycle helmets and follow the same traffic laws as bicyclists. Municipalities will be able to decide where e-bikes may be used on their streets, bike lanes and trails. E-bikes will not be permitted on 400-series highways, expressways or other areas where bicycles are not allowed. Riding an e-bike under the age of 16 or riding an e-bike without an approved helmet carries fines ranging from $60 to $500. For all other traffic offences, e-bike riders will be subject to the same penalties as cyclists.

When you have the electric motor turned on, it engages with your first push of the pedals. The difference in acceleration is startling compared to any other bike I've ridden. In Eco mode, I could sprint from 0 to 20mph in about 200 feet/65m. Switch to Turbo, and it's about 150/30m feet. As I mentioned above, you still have to pedal. The difference with an electric bike is the feeling of getting more bang for the buck. And if you want to be lazy, you can. Stay in third or fourth gear and you'll be able to stay around 18-19mph with minimal effort. But if you want to go much faster than 20mph, you'll need to work.

The first regularly produced device resembling the modern bicycle was unveiled in 1818. It was called the Dandy Horse. The two-wheeled ride-on Dandy Horse was the brainchild of German inventor Baron Karl Drais, and it featured a handle bar, a padded seat, and two inline wheels of nearly equal size. What it did not feature were pedals; this was a "running machine," thus its name in German, Laufmachine. The Dandy Horse saw only a flicker of popularity, and was largely an historical footnote within a handful of years, though its design is nearly mimicked in the child's balance bike of today.
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.[43]
Perhaps the cleverest thing of all about the Electric Brompton is that despite all the extra stuff, it folds up exactly the same as the non-powered variety. It's so simple, and unlike certain folding bikes we could mention, what you're left with is a genuinely small thing, rather than something that's about the size of a bike with the front wheel taken off.
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.

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.

In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895 Ogden Bolton Jr. was granted Template:US Patent for a battery-powered bicycle with “6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel.” There were no gears and the motor could draw up to 100 amperes (A) from a 10-V battery.[3]
Simple, convenient, cheap, and economical—bicycles are one of the world's favorite forms of transportation. But they're not for everyone. They can be hard to pedal up and down hills or with heavy loads, and elderly or disabled people may find them impossible to manage. In the last few years, a new generation of electric bicycles has begun to revolutionize our idea of environmentally friendly transportation. These new cycles have all the convenience of cars with all the simple economy of ordinary cycles. Let's take a closer look at how they work.