Electric motorUpdated 7 months ago
In order to figure out what motor will best suit your needs, there are two questions you need to ask yourself:
- The position of the motor: it can be placed either in the crankset, or in one of the bike's wheels.
- The amount of torque needed: this will depend on the terrain/incline you plan to ride on and the loads (just yourself, your kids, your groceries, etc) you plan to carry.
Motor Position
- Hub Motors (typically located in the rear wheel, but not always): they directly spin the wheel, independent of the force you apply to the pedals & chainring. They are generally found on bikes for smaller budgets. The motor is less expensive, more discreet, lighter (which is handy if you need to lift it frequently) and suitable for mostly flat roads. On the other hand, assistance is often described as less natural. Wear and tear on the cassette, chain, and derailleur is also typically faster than if the motor were located in the mid-drive.
- Mid-Drive Motor: most of of Upway's e-Bikes feature a mid-drive motor. Mid-drive motors are located where the pedals attach to the frame: they apply power to the chain-ring (the part that you apply force to when you pedal). This type of motor is generally more premium and provides assistance proportional to the power of your pedaling. This can make the bike a bit heavier, but central position of mid-drive motors improves the bike's balance and stability. Finally, note that it is easier to change a rear wheel flat because it doesn’t have a motor attached to it.
Left: Rear-Hub Motor on an Aventon Aventure 1 — Right: Mid-Drive Bosch Performance Line Motor on a Benno RemiDemi 9D
To find out more about motors, read our article on how electric motors work.
Speed and e-Bike classes
In the United States, e-bikes are commonly categorized into three classes:
- Class 1: pedal-assist only, with no throttle, and have a maximum assisted speed of 20 mph.
- Class 2: also have a maximum speed of 20 mph, but are throttle-assisted.
- Class 3: pedal-assist only, with no throttle, and a maximum assisted speed of 28 mph.
Local regulations may restrict the usage of certain classes of e-bikes in specific scenarios. For example, some shared multi-use trails might prohibit Class 2 or Class 3 bikes.
Assistance type: throttle vs. pedal-assist
Certain e-bikes are equipped with a throttle mechanism, typically operated by a thumb trigger or twist, enabling the motor to provide power independently of pedaling, thus categorizing them as Class 2 e-bikes. These throttle-enabled e-bikes also incorporate pedal-assist functionality, meaning the motor engages in response to pedaling, but with the added option of throttle activation.
Throttle mechanisms are predominantly found in e-bikes featuring Chinese motors and are typically absent in higher-end models. They offer practical advantages for commuting, facilitating stable travel at very low speeds, such as on sidewalks, and effortless acceleration from traffic lights and stop signs.
Motor Torque
Torque describes a motor's propulsive force: the higher the torque, the more it will help you accelerate uphill. If your trips involve uneven terrain, or if you regularly carry heavy loads (child seat, trailer...), you'll need to choose an electric bike with sufficient motor torque.
Torque is expressed in newton meters (Nm) and is indicated on each bike's product page. As a guide, we recommend different amounts of torque depending on the slope of the terrain you'll ride on, as seen below:
| Type of terrain | Flat | Hilly | Mountainous |
|---|---|---|---|
| Suggested minimum torque | ≥ 20 Nm | ≥ 50 Nm | ≥ 70 Nm |
Do not compare the torque between mid-drive and hub motors. For a similar torque value, a mid-drive motor will be in reality more "powerful": the applied torque available is higher because the torque can be scaled using your gears. As a result, mid-drive motors are typically preferred if you expect a lot of hill-climbing.
There are two important exceptions:
- If you regularly carry a heavy load (children, trailer, etc.), we advise you to select a higher category. For example, select a bike with at least 50 Nm if your route is flat, and 70 Nm if your route is hilly if you plan to bring your kids along on all your rides.
- Conversely, for lighter bikes (under 45 lb), you can get away with a weaker torque.
Motor Brands
Other considerations may come into play in your choice: for example, you may prefer a motor from a well-known, reliable brand (such as Bosch, Specialized, Bafang or Brose). This will facilitate access to spare parts.