You can learn more about the development and axle testing process on this endless-sphere thread. Our ambition is to make this splined axle design into a new standard that we deploy across our entire higher power motor lines to replace axle flats. If you're as excited as us and want to jump right into ordering, we have the first production shipment on hand available in bare motors and complete kits.
A KS LEV Integra dropper post, 130mm of front and rear travel, 27.5-inch wheels, and trail-grabbing 2.8-inch tires make this pedal-assist mountain bike a great option if you want to climb farther to shred longer, but don’t want to lug your bike uphill for ages. The 250-watt motor, placed slightly farther forward than most other bikes to optimize weight distribution and handling, provides a nice boost so you can enjoy the ride up and not be too gassed when you get to the top.
Firstly there's a magnetically-fired locking pin in the rear wheel, triggered by kicking a button on the hub. This is fairly secure in itself and almost impossible to remove without destroying the bike. In London, we'd pair it with a more traditional bike lock so there's a more obvious visual deterrent, though a LED matrix screen on the frame does issue a warning to would-be tea-leafs.
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.

At 42 pounds for a size medium frame (exceptionally light for an urban e-bike), this step-through model’s silent, mid-drive Bosch Active Line motor provides pedal assist up to 20 mph. And its 400Wh battery lasts a claimed 30 to a whopping 110 miles, depending on mode, speed, terrain, rider weight, cargo—all the usual stuff. With 26-inch wheels, 2-inch tires, round aluminum tubes, a swept-back handlebar, Shimano Sora 9-speed components, and an 11-32 cassette, the Parkway looks like an everyday, non-motorized city bike at first glance. But with an array of Bosch e-components—motor, battery, and Purion display—it has the zip to take you farther faster.
At the top end, the 20mph speed limit isn't an absolute, like the speed of light. It's just the most you'll get from the motor. I was able to get it up to 28mph on a flat road (there are no other roads where I live) in Turbo mode and 8th gear, but it took hard work to get there and maintain the speed. The easiest comparison is my mountain bike, where I've hit 23mph on that same stretch of road—and that took a heck of a lot of effort. Exactly how much effort does it take to ride? I have a 15-mile route that I ride on both my mountain bike and cyclecross bike. According to my Apple Watch, I generally burn around 1,400 or so calories on a brisk ride. I'll probably average around 13mph or so on my Marlin and between 16 and 17.5mph on my XO2. I averaged 14.9mph and burned a hair over 1,000 calories with the Bulls Cross E8.
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.
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895, Ogden Bolton Jr. was granted U.S. Patent 552,271 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-volt battery.[5]
"Electric-assisted bicycle" means a bicycle with two or three wheels, a saddle, fully operative pedals for human propulsion, and an electric motor. The electric-assisted bicycle's electric motor must have a power output of no more than one thousand watts, be incapable of propelling the device at a speed of more than twenty miles per hour on level ground, and be incapable of further increasing the speed of the device when human power alone is used to propel the device beyond twenty miles per hour.[66]
The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings, pneumatic tires, chain-driven sprockets and tension-spoked wheels.[10]

In the theoretical electric bike we considered up above, we had the dynamo/motor driving the back wheel directly, simply by pressing on the tire. Most electric bikes work a different way. They have compact electric motors built into the hub of the back or front wheel (or mounted in the center of the bike and connected to the pedal sprocket). Take a look at the hub of an electric bike and probably you'll see it's much fatter and bulkier than on a normal bike. You can read more about how these motors work in our main article about hub motors. 

An electric bicycle is a bicycle with an electric motor used to power the vehicle, or to assist with pedaling. In many parts of the world, electric bicycles are classified as bicycles rather than motor vehicles, so they are not subject to the same laws as motor vehicles. Electric bicycles are one type of motorized bicycle. However, electric bicycles are defined separately and treated as a specific vehicle type in many areas of legal jurisdiction.

The environmental credentials of e-bikes, and electric / human powered hybrids generally, have led some municipal authorities to use them, such as Little Rock, Arkansas with their Wavecrest electric power-assisted bicycles or Cloverdale, California police with Zap e-bikes. China’s e-bike manufacturers, such as Xinri, are now partnering with universities in a bid to improve their technology in line with international environmental standards, backed by the Chinese government who is keen to improve the export potential of the Chinese manufactured e-bikes.[67]

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.

Controllers for brushed motors: Brushed motors are also used in e-bikes but are becoming less common due to their intrinsic lower efficiency. Controllers for brushed motors however are much simpler and cheaper due to the fact they don't require hall sensor feedback and are typically designed to be open-loop controllers. Some controllers can handle multiple voltages.
Ontario is one of the last provinces in Canada to move toward legalizing power-assisted bicycles (PABs) for use on roads, even though they have been federally defined and completely legal in Canada since early 2001. In November 2005 "Bill 169" received royal assent allowing the Ministry of Transportation of Ontario (MTO) to place any vehicle on road. On October 4 2006 the Minister of Transportation for Ontario Donna Cansfield announced the Pilot Project allowing PABs which meet the federal standards definition for operation on road. PAB riders must follow the rules and regulations of a regular bicycles, wear an approved bicycle helmet and be at least 16 years or older. There are still a number of legal considerations for operating any bicycle in Ontario. [9][10][11][12]
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.
Did you know that electric bikes can be used for fitness training? Or that they have been scientifically proven to increase the amount of cycling people do? Or that they have proven health and fitness benefits? Well, it’s all true! Apart from being tons of fun, ebikes can be used to improve health and fitness in many ways. Here are our top posts about how ebikes can improve your health and fitness.
(2) BICYCLE.--Every vehicle propelled solely by human power, and every motorized bicycle propelled by a combination of human power and an electric helper motor capable of propelling the vehicle at a speed of not more than 20 miles per hour on level ground upon which any person may ride, having two tandem wheels, and including any device generally recognized as a bicycle though equipped with two front or two rear wheels. The term does not include such a vehicle with a seat height of no more than 25 inches from the ground when the seat is adjusted to its highest position or a scooter or similar device. No person under the age of 16 may operate or ride upon a motorized bicycle.

Even with cheaper or heavier bikes, once you accept that you are really meant to pedal gently and let the motor do the work, non-speed freaks will get into it. E-bikes are great for commuting and for places that aren't pancake flat. They'll pull you away from the lights quickly, iron out hills and stop you getting sweaty, so you can bin the Lycra and ride in jeans, a suit, or a winter coat.

Some power-on-demand only e-bikes can hardly be confused with, let alone categorised as, bicycles. For example, the Noped is a term used by the Ministry of Transportation of Ontario for e-bikes which do not have pedals or in which the pedals have been removed from their motorised bicycle. These are better categorised as electric mopeds or electric motorcycles.
Electric bicycle fits under the definition of "moped" under Kentucky law. You don't need tag or insurance, but you need a driver's license. "Moped" means either a motorized bicycle whose frame design may include one (1) or more horizontal crossbars supporting a fuel tank so long as it also has pedals, or a motorized bicycle with a step-through type frame which may or may not have pedals rated no more than two (2) brake horsepower, a cylinder capacity not exceeding fifty (50) cubic centimeters, an automatic transmission not requiring clutching or shifting by the operator after the drive system is engaged, and capable of a maximum speed of not more than thirty (30) miles per hour[43][44] Helmets are required.

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 last 8 months we've been wrapping up some long duration testing of Statorade across different hub motor lines and performing experiments confirming its long term stability. These results have us pumped to introduce this motor cooling solution beyond DIY'ers and into wider markets. As an example, have a look at the video we below showing the effect this has on a small direct drive folding bike motor.