Professional electric cargo bike motorization: motor, battery, fleet solutions
Motorizing a professional cargo bike is not simply attaching a city bike kit to a longer frame. A delivery cargo bike or a bicycle taxi starts with a full load, often on an incline, dozens of times a day, and must remain operational throughout the day. The motorization is therefore chosen based on the load, the terrain, and the required service life, and it must remain within the legal limits for electric bicycles if the bike is used on public roads without registration.
The essentials
- The main challenge with a cargo bike is starting with a heavy load on an incline, not its top speed.
- To remain classified as an electric bicycle, the motor must comply with the definition in the Highway Code: it must only provide assistance when the pedals are being turned, and its output must be cut off at 25 km/h.
- The battery range is calculated based on a typical day of use, with a margin to account for cold weather and wear and tear.
- For a fleet of vehicles, remote monitoring (battery charge, faults, location) is just as important as the motor itself.
- A bicycle that carries passengers requires smooth handling and braking that is appropriate for the weight.
What the law requires of an electric cargo bike
In France, Article R311-1 of the Highway Code defines the "pedal-assist bicycle": a bicycle equipped with an electric auxiliary motor with a maximum continuous rated power of 0.25 kilowatts, where the assistance is gradually reduced and then cut off at 25 km/h, or earlier if the cyclist stops pedaling. This regulation allows riders to operate the vehicle without registration or a license.
Here are two practical implications for a cargo bike:
- The continuous nominal power is limited, but the available torque at startup depends on the motor and its transmission. This is where the ability to climb a hill with a load comes from.
- Beyond this framework, the vehicle changes category (becoming a moped), requiring registration, insurance, and approval. Our guide electric bicycle, speed pedelec, and moped details this distinction. The regulations are constantly evolving: please check the current version on the Légifrance website before starting a production run.
Hub motor or mid-drive motor
The two architectures are both found in cargo bikes, and each has its own advantages.
| Architecture: | Key Features: | Weaknesses: |
|---|---|---|
| Mid-drive motor (located at the crank) | Enjoy the bike-like speeds, good torque for climbing hills, and a balanced weight distribution | Utilize the chain and sprockets more extensively; this is more complex to integrate on certain frames |
| Motor in the wheel hub | Simple, transmission-independent, and requiring minimal maintenance | No gear ratio: the torque on inclines depends solely on the motor, and a heavier wheel will affect performance |
On a heavy cargo bike used in hilly urban environments, a mid-drive motor is often preferred because it utilizes the bike's gears. On a flat cargo bike that needs to be maintained quickly and operates in a fleet, a hub motor has the advantage of simplicity. A complete comparison can be found in our guide mid-drive motor vs. hub motor.
Size the battery based on the actual usage scenario
The best approach starts with a typical day: the number of kilometers traveled, the elevation changes, the average weight carried, and the number of stops and restarts. We measure or estimate the energy consumed during that day, and then add a safety margin. In practice, three factors often impact this:
- The cold, which reduces the available energy of lithium batteries in winter.
- Wear and Tear: A battery loses capacity over time with each charge cycle, and it needs to still provide sufficient power even at the end of its lifespan.
- Heavy acceleration**, which consumes significantly more power than cruising at a constant speed.
For a fleet of vehicles, having two smaller batteries per bike that can be quickly swapped out is often better than having a single, very large battery: the bike doesn't stop while the battery is being changed. The basic calculation (Wh, Ah, voltage) is explained in our guide for calculating battery capacity.
Passenger transport: comfort and braking
A passenger bike or cargo bike is not driven like a delivery bike. Passengers do not have handlebars to hold onto, so the motor assistance must increase gradually, without sudden surges at the start. This is adjusted in the controller, using the torque ramp-up curve.
The braking system must be sized to handle the total weight, including the bike, rider, and any passengers, especially when going downhill. Hydraulic disc brakes, large rotors, and regular brake pad checks are essential. The electric motor's regenerative braking can assist the mechanical brakes, but it never replaces them.
Tracking a fleet of cargo bikes
As soon as you start using multiple electric bikes, the question shifts from simply "is it working?" to "which one is charged, which one has a fault, and where is it?". A controller and a BMS that communicate allow you to track this information: battery level, history, faults, and operating hours. This is the role of RageLink, our ecosystem of controllers, displays, and telemetry, which is currently on a waiting list.
This is also what the page on our engineering department's website, dedicated to tourism and urban mobility, calls for: a known and predictable range for planning tours, vehicle location and status that are easily readable at a glance, and an adjustable speed depending on the location.
Here's an example: Drop cargo bikes at the Olympic Games
Drop offers cargo bikes designed to carry two passengers. A fleet was deployed during the 2024 Olympic Games, using the Palladium model, and Rage Mechanics provided the complete motorization system. The challenge presented was typical of the industry: a cargo bike carrying two passengers operates all day, often starts with a load, and must remain available throughout the entire event. The case study is available on the page Drop.
Workshop tip
Before choosing a motor, load a bike with its actual weight and ride up the steepest hill on the route, noting the time taken and the rider's condition. This simple test reveals more about the expected motor performance than any technical specification sheet. Only then should you determine the appropriate motor size.
For a series production project of cargo bikes or e-taxis, our engineering department designs the complete motorization system, sized for the specific machine. The general method is described in our guide on how to electrify a machine.
Frequently Asked Questions
Can an electric cargo bike exceed a speed of 25 km/h?
With electric assistance: no. The Highway Code stipulates that motor assistance must be cut off at 25 km/h. The cyclist can go faster using only their leg power, but a bicycle where the electric assistance continues beyond this speed changes category and must be registered.
Does a more powerful motor help when climbing hills with a load?
When it comes to climbing hills, torque at the wheel is the most important factor. A mid-drive motor that utilizes the bike's gears, or a hub motor specifically chosen for its torque, will perform better than a motor that is simply more powerful on paper.
Should electric bikes have one or two batteries?
For intensive use in fleets, two swappable batteries prevent the bike from being immobilized during charging. For lighter use, a single, appropriately sized battery is sufficient.
Is it possible to retrofit an existing fleet of cargo bikes with electric motors?
Often, yes, provided the frame and brakes are in good condition. We first evaluate a bicycle to validate the solution, and then we apply it to the rest of the fleet.
What kind of tracking is available for a fleet of vehicles?
At a minimum, the system should display the battery charge level, any detected faults, and the operating hours for each e-bike. Remote location tracking and speed adjustment capabilities are useful when the e-bikes are operating in different locations.