In a friction drive motor, a small, solid wheel rotates against the side of the tire in order to drive it. The first motorcycles used the same concept, with a motor mounted above the front wheel. The problem is that the drive rubs at the side of the tire. It's inefficient, and it quickly wears the sidewall away. Tires need to be replaced every couple hundred miles. For this reason, you'll seldom see electric bikes with this type of drive anymore.
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).
Included in this shipment are the much awaited 3540 motors with their slick "UFO" design. These are the replacements for the older square style "H" motors, you may have noticed that this change was implemented last year with the 3525 front and rear motors. As always, we have the motors customized with a 10K NTC thermistor for thermal rollback using the CA3.

One of the items we demonstrated at the show is the new GMAC motor series. This is a powerful clutchless geared hub motor developed over the past 2 years in partnership with MAC motors, using a custom axle with an integrated splined torque arm. Imagine a MAC motor with perfect frame fit for modern bicycles, zero torque transmission on the dropouts, and phenomenal regenerative braking control.
But electric bicycles—e-bikes—are new territory for me. Broadly speaking, there are two basic options in e-bike land: power-on-demand and pedal-assist. With the former, the rider can control the speed with a throttle instead of just pedaling. Think moped but with an electric motor instead of internal combustion. Pedal-assist, by contrast, requires the rider to do some of the work. The electric motor won't engage unless the rider is pedaling.
I have been able to find ebikes of all speeds out in the wild and after years of riding and a reflective posture for the law, I see that lawmakers were thinking less about me and my practical wants as the user, and more about the mass motor vehicle driving public, their perceptions and expectations of ‘typical bicycle speeds’ on the roads and paths. So the laws were made to bicycle NORMS, not the potential performance limits for users.
"Moped" means a device upon which a person may ride which has two or three wheels in contact with the ground, a motor having a maximum power output capability measured at the motor output shaft, in accordance with the Society of Automotive Engineers standards, of two horsepower (one thousand four hundred ninety -two watts) or less and, if it is a combustion engine, a maximum piston or rotor displacement of 3.05 cubic inches (fifty cubic centimeters) and which will propel the moped, unassisted, on a level surface at a maximum speed no greater than thirty miles per hour; and a direct or automatic power drive system which requires no clutch or gear shift operation by the moped driver after the drive system is engaged with the power unit.

"Bicycles" and "Electric Bicycles" are legally defined in the Texas Transportation Code Title 7, Chapter 551 entitled "Operation of Bicycles, Mopeds, and Play Vehicles" in Subchapter A, B, C, and D.[131] Under Chapter 541.201 (24), "Electric bicycle" means a bicycle that is (A) designed to be propelled by an electric motor, exclusively or in combination with the application of human power, (B) cannot attain a speed of more than 20 miles per hour without the application of human power, and (C) 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[132] 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.

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.
Electric mountain bikes have garnered a lot of attention for their ability to help riders go higher, further, and faster on the trail. As a result, there have been some impressive new eMTB models to hit the market in recent years, making it easier than ever to head off-road. Our favorite is the Haibike SDURO HardNine, which comes equipped with a 350-watt Bosch Performance CX drive and a 500 watt-hour battery. This gives it a range of up to 70 miles, along with a top speed of 20 mph, which is plenty fast on singletrack.
In a parallel hybrid motorized bicycle, such as the aforementioned 1897 invention by Hosea W. Libbey, human and motor inputs are mechanically coupled either in the bottom bracket, the rear wheel, or the front wheel, whereas in a (mechanical) series hybrid cycle, the human and motor inputs are coupled through differential gearing. In an (electronic) series hybrid cycle, human power is converted into electricity and is fed directly into the motor and mostly additional electricity is supplied from a battery.

That aside, the Axis is a fantastic e-bike. At 'only' 16kg, it's almost lively by e-bike standards, but it also feels rock solid. It's geared too low in my opinion – I think it's fair to say I am not the target market – but in 8th, you can breeze on past the legally mandated, electrically-assisted 15.5mph. The hydraulic disk brakes will then bring you to a pleasingly rapid dead stop. The range and charging time are good, too. Cheap it is not, mind you.
10. Limitation of Liability: By entering you agree to release and hold harmless Electric Bike Technologies INC. and its subsidiaries, affiliates, advertising and promotion agencies, partners, representatives, agents, successors, assigns, employees, officers and directors from any liability, illness, injury, death, loss, litigation, claim or damage that may occur, directly or indirectly, whether caused by negligence or not, from (i) such entrant's participation in the sweepstakes and/or his/her acceptance, possession, use, or misuse of any prize or any portion thereof, (ii) technical failures of any kind, including but not limited to the malfunctioning of any computer, cable, network, hardware or software; (iii) the unavailability or inaccessibility of any transmissions or telephone or Internet service; (iv) unauthorized human intervention in any part of the entry process or the Promotion; (v) electronic or human error which may occur in the administration of the Promotion or the processing of entries.
"Moped" means a device upon which a person may ride which has two or three wheels in contact with the ground, a motor having a maximum power output capability measured at the motor output shaft, in accordance with the Society of Automotive Engineers standards, of two horsepower (one thousand four hundred ninety -two watts) or less and, if it is a combustion engine, a maximum piston or rotor displacement of 3.05 cubic inches (fifty cubic centimeters) and which will propel the moped, unassisted, on a level surface at a maximum speed no greater than thirty miles per hour; and a direct or automatic power drive system which requires no clutch or gear shift operation by the moped driver after the drive system is engaged with the power unit. 

Motor-driven cycles may be operated on the roadway without registration, but the operator must have a driver's license.[85] The cycle may not be operated on any sidewalk, limited access highway or turnpike. If the maximum speed of the cycle is less than the speed limit of the road, the cycle must operate in the right hand lane available for traffic or upon a usable shoulder on the right side of the road unless the operator is making a left turn.
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.[38] 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%.[39][40] In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also an efficient means of cargo transportation.
Photo: Zap Electric's power-assist kit turns a conventional bike into an electric one. There's a bolt-on DC electric motor (weighing just over 3kg or 7lb) just above the back wheel, behind the police officer's foot, pressing against the tire and driving it by simple friction. The motor's powered by a compact lead-acid battery (weighing about 5.5 kg or 12 lb) inside a protective nylon bag. This kit adds quite bit of weight to the bike, but gives extra range and speed when needed. Photo taken in Santa Rosa, California by Rick Tang courtesy of US DOE/NREL.

State laws tend to intermix the source of power as either gasoline ICE or electric drive. This is unfortunate because that neutralizes the environmental advantage of an ebike over an ICE moped. It also misrepresents the contrast in power output levels between an ICE and electric motor system. 50cc gas mopeds/scooters have a 2.5-4 HP rating, while the 20+ mph electric bikes will be 1-2hp, and ride much closer to a normal bicycle compared to a gas powered, 2.5hp moped. E-mopeds will weigh 55-70lbs. Gas mopeds and scooters are typically over 120lbs. E-mopeds are still electric bikes that get valuable power assist from human pedal effort and are usually much quieter.

Every bike on this list has been thoroughly evaluated and vetted by our team of test editors. We research the market, survey user reviews, speak with product managers and engineers, and use our own experience riding these bikes to determine the best options. Our team of experienced testers spent many hours and miles using these bikes for their intended purpose. We’ve commuted to and from work on them, used them to stock up on groceries and beer, tested their passenger-hauling capability, ridden them on questionable terrain (just to see how they’d handle), and run their batteries down to officially see how long they last on one charge. We evaluated them on performance, price, comfort, handling, value, reliability, fun, and overall e-factor to come up with this list of bikes that will best serve the needs of anyone looking to add a little pedal assist to their ride.
The entire drive system is neatly incorporated into the bike's design for optimal weight distribution and the ultimate in sexy design, while users control torque and power output, which peaks at a surprisingly punchy 530W, via a cool Mission Control App that can also be programmed to a time or distance parameter to ensure there's enough power to get you home.

Seth Miller said he founded the company after his first electric bike was stolen from where it was parked in front of the midtown office building where he worked. The company that manufactured the bike had disbanded, so he started researching different suppliers. He soon discovered that a majority of the e-bikes sold in the US are just cobbled together from a variety of off-the-shelf Chinese-made parts found in a catalog. It sounded simple, so Miller figured he’d try it himself.

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