When someone hears electric bicycle, the first image they imagine may be a scooter or electric motorcycle - but they actually look pretty different. Just picture a regular bicycle, then add several electrical components to it like a motor, a battery, and a controller – all seamlessly integrated into the design. These items make up the fundamentals of all electric bicycles on the market!
Electric bikes pedal and handle just like a regular bicycle. By and large, an electric bike will use the same parts too. The electric component is meant to augment human power, not completely replace it. It makes obstacles like hills and headwind more manageable and allows you to travel further without getting as tired.
See our diagram for a more detailed look at how electric bikes work including the motor, battery, drivetrain, and charging process:
Comfort and quality of the components are still as important on an electric bike as they are on a regular bicycle. But now, there are a few more things you need to consider.
Electric bike motors come in a wide variety of power ratings, from 200W to 1,000W or more. The legal limit in the US is 750W, although different states can set their own limits.
Think of this limit kind of like horsepower. A higher rating means that the bike will be able to pull more weight with greater ease – but at the expense of using more battery capacity while doing so. Consequently, a 750W motor will drain the battery much quicker than a 250W one, but it will be more powerful.
One more factor needs to be considered, however. The design and location of the motor plays an important role in how electric bikes work.
The most common type of motor for electric bikes is called a hub motor. It is generally integrated into the rear or front wheel. When engaged, it pulls or pushes the wheel along. Although this system works well, it has one key disadvantage. Since it is not connected to the bike’s gears, it loses efficiency on hills and varied terrain. Imagine driving a vehicle in just one gear the entire day. It will get you places, but it won’t give you the optimum amount of torque or speed that you get with a full gear range.
At EVELO, we offer a patented mid-drive motor, which is integrated with the crank and the gears. This adds several advantages:
Increased performance while spending less battery energy, since the mid-drive motor uses the bike’s existing gears;
Much better hill climbing power, since you can switch gears depending on the incline; and
Handling is improved, since the motor is positioned closer to the ground, keeping the weight centered and low.
Since the battery affects the weight, style, and range of the bike, its choice is crucial. Batteries play a huge part in how electric bikes work. The majority of the batteries you’ll find offered on the market fall into one of the following two categories:
These batteries were once the standard battery type for most electric scooters and electric bicycles. These days, most electric scooters still use SLA batteries, while electric bikes (which often require human input) have opted for newer battery technologies to keep the bike as lightweight as possible.
Inexpensive
Heavy and bulky
Offer a shorter riding range
Shorter life span of about 100-300 full cycle charges
Require more maintenance, and need to be charged immediately after use
These are the newest technology in batteries. A lithium battery has a lifetime roughly 2-3 times that of an SLA battery. Lithium batteries are much lighter and also are largely maintenance-free.
Lightweight – high-capacity, 36V10Ah Lithium-Polymer batteries can weigh as little as 6 pounds!
Offer a longer riding range – battery can travel up to 40 miles in pedal-assist mode (or 20 miles on throttle-only).
Longer life span of about 800 charges or 3 years of virtually daily use
More expensive – starting at about $1,500 to $3,000 and above
Available in a variety of styles, the controller lets you operate the electric assistance on your electric bike and is an important part in how electric bikes work. The controller is located on the handlebar for ease of use. There are two main styles of controllers – pedal-activated and throttle-based controllers.
Pedal-activated systems offer electric assistance as you press down on the pedals. There is no need to engage a throttle – simple pedaling will do the trick. Electric bikes with pedal-activated systems have a controller mounted on the handlebar that lets you adjust the level of assistance that you receive as you pedal. You can dial in the amount of assistance you want, ranging from no assistance to a great deal of assistance.
Throttle-based controllers work with a simple throttle mechanism. The throttle will either be a twist-grip type or a thumb-press type. With a throttle, you simply pull back or press the throttle to receive the electric assistance. Some electric bikes require nothing more than activating the throttle, allowing you to ride without pedaling.
By and large, electric bikes are simple to use, ride, and maintain. Overall, they require little maintenance beyond that which a standard bike requires.
Electric bicycles are designed to be very easy to operate. As a rider, you have three modes of operation available to you:
At any time, you can pedal an electric bicycle just as you would with a regular one. There is no extra resistance created by the motor, so it will feel exactly as a regular bicycle would. Depending on the model you purchase, your bicycle will come either with a 3 gears or 8 gears or a special NuVinci® N360™ internal drivetrain that provides you with unlimited gears.
In this mode, you can take advantage of combined human plus electric power. Once you turn on this mode via the on/off button on the handlebars, the motor will gently provide electric power as you pedal. You can still switch gears as the terrain changes to take advantage of more torque or faster speed. It’s an amazing feeling to use pedal-assist mode, as it makes cycling effortless, flattens out the hills, and frees you to just enjoy yourself and the scenery.
Pedal-assist mode provides three levels of assistance: Low (30%), Medium (60%) and High (100%). The percentage simply indicates how much additional power the motor will provide to complement your pedaling. The low setting adds an additional 30% of power to your pedaling, while High essentially doubles it. A simple press of a button switches you through the different levels.
This mode of operation allows you to sit back and take a break, as you let the motor do the work. To use “electric only” mode, simply twist the throttle located on the left handlebar and you’ll feel the motor kick in and propel you forward. Keep the throttle turned to continue along or let go if you’re ready to start pedaling or wish to come to a stop. Please note that due to Federal regulations, the top speed in electric-only mode is limited to 20 miles per hour.
Electric bikes are still a fairly new concept in the US, so there is a lot of confusion about how the law views them. Federal law considers electric bicycles in the class as regular bicycles, provided they meet two conditions: (1) the top speed in “electric only” mode is 20 miles per hour; and (2) the motor power must be no more than 750W.
EVELO electric bicycles meet both of the federal requirements. We cap the top speed in “electric only” mode at 20 miles per hour, although you can of course go faster on your bike with pedal power if you wish. Our motors are rated at 250W, which is well within federal limits.
Consequently, electric bikes do not need a special registration, license, or insurance to operate. Moreover, they enjoy the same privileges as regular bicycles, such as being allowed to travel in available bike lanes.
However, different states have their own special requirements regarding electric bike use. While most follow the federal lead, some do vary. If you have questions about how electric bikes work in your state, you can get in touch with us and we’ll point you in the direction to find out additional information for your state. For your own personal safety, we recommend helmet use and lights and reflecting gear, even if the law does not specifically require them.
When the COVID-19 pandemic forced commuters to rethink their use of public transport, the e-bike market boomed, since it offers a solution to active travel that's accessible to more people regardless of their physical fitness or abilities. With electric bikes now thriving, curiosity is being sparked, with more people than ever keen to give them a try and asking all manner of questions about them.
What are the technical concepts and limitations of electric bikes? How will burgeoning e-bike development influence your cycling choices in the near future?
The notion of battery-assistance for bicycles is not new, but two issues have bedevilled e-bike development: energy portability and drivetrain integration. A decade ago the battery technology simply did not exist to supply batteries which were light and compact enough, with adequate energy density and affordable pricing.
Hybridising the bicycle drivetrain was also equally challenging. Power surges ruining your pedal rhythm can make for an unnatural riding experience, and calibrating the electric motor action and rider cadence can be a complicated affair.
Of all the manufacturers, Shimano is hugely influential in the cycling world, and the Japanese company produces an enormous catalogue of parts. Alongside SRAM, Shimano's groupsets are among the most widely known and distributed in the world.
So when Shimano moves on a new product trend you know it's significant, due to the sheer scale of research and manufacturing resources under the Japanese brand’s command. With the unveiling of its EP8 e-bike motor in late 2020, Shimano signalled a commitment to the battery-assisted bike movement.
Sensors measure your torque input, cadence and speed, performing more than a thousand calculations a second. Once the e-bike’s sensors detect a need for battery-assistance, reacting to a master algorithm controlling the entire system, power is released from the battery pack to energise electromagnets in the motor.
No longer does a throttle actuate the motor's input, with the today's best electric bikes, your pedalling input is accentuated by the motor. This provides a smooth pedelec ride, rather than a moped-style twist and go.
An e-bike’s mid-drive motor has both permanent- and electromagnets, the latter which are energised by power drawn from its battery pack.
Permanent magnets sit in the mid-drive motor’s centre, whilst electromagnets (recognisable due to the wiring wrapped around them), surround the rest of the casing. Transistors manipulate the polarity of these electromagnets, which spin the shaft, adding pedal assistance to your ride.
Beyond the quality of your software coding, the orientation and quality of those magnets are what makes an e-bike drive system perform. The trick is to get the repelling and attracting forces between the magnets to work as best possible, which can be challenging.
Using superior quality neodymium magnets, which are very powerful, can increase your motor system’s potency and range, without requiring a higher capacity battery.
In terms of packaging as a performance feature, the Halbach array method of orienting permanent magnets can double power, but it is a challenge to bond magnets in this way, especially in a compact mid-drive motor configuring. Production costs with the Halbach array technique are also quite often prohibitive.
Colnago's E64 looks noting like an e-bike, but is (image credit: Colnago)
(Image credit: Colnago)
The consumer electronics and automotive industries have been meaningful drivers of lightweight energy-dense battery development, ideal for delivering the power and mass profile that required in an e-bike application.
With more potent battery chemistries available, designers are finally capable of packaging the e-bike’s distinguishing components in an elegant and practical way. Some current e-bikes are very difficult to tell apart from a non-assisted frameset. The Ribble Endurance SL e comes to mind as an example.
E-bike design theory is not overly complicated in principle. Unlike a moped, the e-bike provides pedal assistance through the bottom-bracket motor, as required. It has no rider modulated throttle, which is an important distinction.
As far as the best electric road bikes are concerned, your bottom bracket and lower downtube section are the structurally most important frame areas. The battery is housed as part of the downtube and nearly all e-bikes are designed to use the mid-drive motor configuration, which resides in your bottom bracket, between the cranks.
Brushless electric motors convert the battery’s energy to pedalling assistance, but they do spin at a much higher rotation than your riding cadence. Mid-drive motors use internal gearing to mediate their power output and your riding cadence, enabling rider and onboard energy source to achieve synchronisation in pedalling.
What differentiates a great e-bike from an awkward riding one, is the sophistication of its mid-drive motor’s control software. E-bikes equipped with meticulously calibrated and tested lines of code to control their response to your pedal stroke and cadence ride in a far superior way.
Sensors measure your torque input and cadence, then calculate the appropriate linearity of motor assistance required. The best e-bikes should never feel artificially electromechanical, undermining a ride with power surges as terrain gradient suddenly changes or you are shifting gear.
Product managers in the e-bike segment benchmark the feeling of riding with a tailwind as the ideal. The latest generation of e-bike control software algorithms create a sense of gliding along at higher speeds, whilst maintaining a natural cadence.
An exploded view of Specialized's Turbo Creo shows the modern e-bike's configuration (image credit: Specialized)
(Image credit: Specialized)
Competition drives innovation and scale reduces price. As demand increases for e-bikes in all cycling disciplines, component suppliers could start offering better batteries and drive motors at more affordable prices.
The battery-assisted nature of an e-bike ensures that cyclists are unlikely to witness a ‘power output war’ between suppliers – due to the absence of a hand throttle and the risk of triggering strict government speed and safety regulations.
As with other areas sof cycling, reducing mass and aiding efficiency is the goal. Enhanced energy density in the battery systems will see improved range with equivalently lower mass, instead of engineers chasing higher speed and acceleration characteristics with more powerful motors and larger battery packs.
Shimano’s new EP8 motor is evidence of this approach and tallies notable gains in its four-year development cycle since the original E8000 STEPS drive-motor system was launched. It is 21% more powerful than an E8000 system, has dropped 10% in mass and is a similar percentage smaller in terms of overall size, making it much less of a hindrance to package for frame designers wishing to integrate e-bike functionality into an existing or new model line.
Shimano’s lasting commitment to mid-drive motor development and drivetrain integration software is indisputable with the launch of its new EP8 system.
Of all the traditional cycling component brands, Specialized has shown the greatest willingness to invest in e-bike technology, with its own engineering assets. Shimano's new EP8 system should also trigger broader competition between these larger cycling companies, which ultimately benefits the customer in terms of choice and diversity of price.
Don’t expect your future e-bike to be massively powerful and capable of outrageous speeds. That has never been the purpose of battery-assisted cadence. But if you need something to defeat that awful late afternoon headwind or link some steep climbs on a route in fading light, increased rivalry in the e-bike market will deliver you a much better battery-assisted ride.