eBikes Part 2: How Do They Work?

eBikes Part 2: How Do They Work?

In eBikes Part 1: Should I Buy One? I talked about what an eBike is and if you should consider buying one. I gave reasons why you might favour getting an electric bicycle, the benefits, and any shortcomings.

Here in Part 2, I get into the different designs, types of motors, battery power and options that exist. My first comment is that there are a lot of choices.

Technology is rapidly changing and what you see today will likely evolve greatly in the next decade. Exciting stuff!

There has been a lot of change in the design and efficiency of electric-powered bicycles. Only now after years of existing on the fringe as a concept that had weak motors and large, heavy batteries, things have improved immensely.

Prices have come down (though they’re still not cheap) and eBikes have become more reliable. It seems now everyone is making them. So this is a good time for me and maybe you to start paying attention to what is out there.

eBikes are electric motor-assisted bicycles. These are two- or three-wheeled vehicles that have pedals and are built on a bicycle frame. Batteries add weight and more hauling power so eBike frames are thicker (and their tires wider) than those of most traditional bikes.


Two Types of Electric Motors

There are two popular ways of propelling these bikes. One is a hub drive; the other is called a mid-drive. You can also retrofit your existing bike, typically done with a front hub motor. It’s a cheaper way to go electric, but it’s not ideal, so I will leave that method for another article. And In Ontario, an electric motor can not exceed 500 watts.

Let’s focus on bikes that are built to be electric. Beyond where the motor is placed, there are many variations in design. Where is the gearing (if at all): at the crank, on a rear wheel cassette, or in an internal hub? How many gears does it have? What’s the span of gearing from small to large? How smoothly does it shift? Does it have a chain or a belt drive? (Bike chains have been known to snap from high torque from the motor. Some bikes have rubber belt drives that perform better and weigh less.)


rear hub gear motor
rear hub gear motor

rear hub motor
rear hub motor

Hub Drive Motors

Let’s first look at the cheaper design to build, a rear hub drive. The electric motor is located in the rear wheel hub, which adds more weight to the rear. There will be a throttle on the handlebar to vary the motor speed. You can add your pedalling to the mix or not. As you shift your bike gears and pedal the motor works independently and does not benefit from what gear you are in.

The riding experience is hard to explain. When you turn up the speed the motor/rear wheel pushes you. Some bikes can lurch you forward with a lot of zip and you can coast along without pedaling at all. This of course eats into your battery life. And for some, this may feel unnatural compared to the cycling you know and not intuitive to get used to.

There are two types. The first is a gearless direct drive motor. Electric motors like to spin fast; with no gears they turn slower, at the rate your tire turns. These are larger, heavy units. On hills, they work hard and do not fare well if there are many climbs; they could overheat and burn out. On the plus side, no gearing makes them quiet and expensive models come with regenerative braking so they can charge the battery going down hills a little bit.  

The second kind of hub motor has internal gearing. Smaller in size and lighter, it can spin faster, putting out more power as the gearing ratio reduces the revolution speed to match tire rotation.  These are better suited for low speed, hills, and cargo. Most have a freewheel so you can pedal without the motor relatively easily. They are cheaper to build, but the moving gears will wear out in time. Low-quality gearing may only get you a few thousand kilometres before needing servicing. 

mid drive motor
mid drive motor

Mid Drive Motors

These electric motors are housed down in the pedal crank area, a more balanced, central location. This is a pedal-assisted design: when the rider pedals, the motor turns on and adds extra power to the pedal stroke. Because it’s connected directly to the drivetrain chain and rear gearing cassette, you can shift gears to improve the motor’s efficiency.

The rider can also control the motor output level by pushing a button on the handlebar: a popular Bosch system has Eco, Tourist, Sport, and Turbo. You can also ride with the motor off and only use it when you see a hill or get tired.

Because mid-drives are lighter, have more power (torque), and use battery energy more efficiently, they are better for longer distances and hill climbs.  

The ride feels more natural, with an added push, similar to the way you ride your regular bike, but with the extra bulk.

Mountain bikes have mid-drives to take on steep hills and keep the weight down, which is important for proper balance in the saddle while manoeuvring obstacles. If you’re looking for an e-MTB, compare the torque output of motors, battery demands and weight, since hill climbing is a big part of the ride, and the bike must perform well in tough conditions. 

Road race bikes use small mid-drives to stay light and integrated with the bike’s appearance. Some motors only add a small extra kick to your pedalling and cannot take on big hills by themselves.


removable battery
removable battery


Rated in watt hours (wh) 500 wh is plenty of juice to get around. You will need more for aggressive MTB riding.  These lithium cell packs are expensive, well over a thousand dollars for larger ones. The bigger the pack, the more reserve power you have for quick bursts and longer distances. It’s all proportional and depends on the way you ride and the terrain you ride over and how much you depend on the electric motor. 

Batteries are still heavy, and where they are mounted will alter the balance and feel of your ride. Most are either attached to the rear rack or mounted on the frame down tube.

Using the right gearing, as you do on a regular bike, will help greatly. Shift down when you meet a hill, and shift up as you go faster – this puts less strain on your bike parts and battery life. I recommend downshifting before stopping to make it easier when you start again. Even though you can go without pedalling from a standing stop with a hub drive, it is wiser to pedal initially to get you going and not stress out the motor.

As with cell phones, the lithium batteries in bikes can catch fire if they overheat or malfunction. So buy a good product that has been lab tested and keep an eye on it when it’s charging.

With most bikes, you can detach and take the battery with you (that’s a good thing). There may be an option to add an extra battery to the frame to extend your range to over 100 km a day of pedal-assist riding.

MTB eBike controls
MTB eBike controls

Extra Options

With good design (which can be more expensive) comes electronic onboard to sense your cadence and torque or throttle control to help you manage the efficiency of the ride. Good mid drive motors will pause for a moment every time you shift so as not to stress out the drive train. 

Controls can be as simple as two buttons or a leveller to change your speed or as fancy as a coloured screen full of data and settings. Displays are mounted on the handle bar and/or crossbar of the bike.

The electronics on your bike can tell you how much reserve power you have and calculate by the way you ride how far you can go. They can be your personal trainer and can track your distance, speed, average them out, and connect with your cell phone app. On some bikes, you can lock the motor with your cell phone and track the bike if it gets stolen. Walking mode enables the bike motor to roll slowly as you walk beside it.

Front and rear lights often come with the bike. Racks seem to come with commuter bikes half the time as they may already be housing the battery. Tire fenders and shocks on the front forks and seat post are also a common add-on.

All eBikes appear to have disk brakes, as they do need them to slow down that extra weight. With the added motor power, some designs seem to not care how much extra steel they use. This in turn has the bike fitted with fatter tires, something you may not care for.

ABS brakes (anti-lock braking system) as you have in your car, are new feature in high end mountain bikes. The industry claims it is a game changer, do we really need this?

Rad Mission
Rad Mission

cannondales eBike
Cannondales eBike

RadRunner 2
Rad Runner 2

Rad Mini 4 folding bike
Rad Mini 4 folding bike

So what will work for you?

Well, it depends. A geared motor will keep things relatively lightweight and can be fit into a bike frame to not look so “electric” and be stealthy, with proper shifting you can increase your range. 

If you want to ride more on motor power alone, at a faster speed on fewer hills, then a hefty, well-made hub direct drive motor might be what to look for. 

If you are just doing short pleasure cruises on flat routes or hauling cargo then the larger frames, tires and added weight that comes at a lower cost may be fine with you. But for more distance, a lighter, more nimble frame and/or a more stylish look, expect to pay more.

Truly, if you’re unsure you need to visit a bike shop, ride a few types, and compare to see what feels good for you and meets your cycling needs.

I had my first experience riding on a commuter eBike in Holland this spring. Since then, I have demoed a few here in Toronto and my wife Teresa just bought a blue Trek +3 Verve Lowstep. Does she love it? When I see her biking to work on a cloudy day, I know she does. Because if she did ride at all before, the weather had to be perfect, lol.

There are so many choices, from folding bikes to kid carriers to $10k MTBs that can take on anything. Whatever kind you’re wishing for, I hope this sorts out some of the mysteries of buying an eBike.


May your future be electrifying – Dan Roitner


Have your read eBikes Part 1:  Should I Buy One?

new ebike
Teresa’s new set of wheels

cargo bike

The Future of Electric Drivetrain Tech

Hub vs Mid Drive Motors

How Does a Electric MTB Work

Things Every eBike Rider Should Know

some photos courtesy Bosh & Rad Bikes

Some links on this page take you to other sites that I believe offer good quality products. I may get a small referral fee if you buy items at these suppliers using my links. This is at no extra cost to you.

October 7, 2022No comments,

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Hey, this may be interesting for you: eBikes Part 2: How Do They Work?!

This is the link: https://ontariobiketrails.com/ebikes-part-2-how-do-they-work/

Lets get together and do a ride soon.