The Brompton folding bike, synonymous with urban mobility, is a marvel of engineering, packing convenience and performance into a compact frame. Brompton e-bike conversion kits, a perfect way to electrify your existing Brompton without sacrificing its iconic foldability.
The Iconic Brompton Folding Bike
Lightweight and convenient, Brompton folding bikes have redefined urban mobility. Handcrafted in London, these bikes are designed to be compact, lightweight, and incredibly easy to fold, making them perfect for commuting, traveling, or simply navigating tight spaces.
Brompton’s Electric series offers the same convenience and portability with the added power of an electric motor, boasting a range of up to 45 miles and a quick-charging detachable battery.
Electrify Your Brompton: Top 5 E-Bike Conversion Kits
If you already own a Brompton and are looking to add electric assistance, conversion kits provide an affordable and flexible option. These kits allow you to seamlessly electrify your existing bike while preserving its iconic foldability and portability.
Below are our top choices of electric conversion kits specifically designed for Brompton models, combining performance, simple setup, and lightweight design.
| Kit Name | Position | Motor Power | Torque | Battery Range | Weight | Top Speed | Installation Time | Compatibility | Price (£) | Price ($) |
|---|---|---|---|---|---|---|---|---|---|---|
| Swytch Kit | Front Hub | 250W | 40Nm | 15 km (Air), 30 km (Max) | Motor (1.5 kg) + Battery (1.1–1.5 kg) | 15.5 mph (25 km/h) | 30 minutes | Brompton and most folding bikes | £499–£649 | $625–$815 |
| Boost Bike Kit | Rear Hub | 250W | Not specified | Up to 30 km | 2.5 kg (including motor) | 15.5 mph (25 km/h) | Less than 20 minutes | Designed specifically for Brompton | £995 | $1,250 |
| Cytronex Kit | Front Hub | 250W | Not specified | Up to 40 km (25 miles) | 1.5 kg (Battery) | 15.5 mph (25 km/h) | 30–45 minutes (self-fit) | Brompton | £1,145–£1,200 | $1,250–$1,320 |
| Byqee F23 Kit | Front Hub | 250W | 45Nm | 40 km (or up to 80 km with extra battery) | Motor (1.2 kg) + Battery (1.2 kg) | 15.5 mph (25 km/h) | 15–20 minutes | Brompton, Dahon, Carraro, and Tern | €945–€1,090 | $1,020–$1,180 |
| ARCC Brompton Kit | Front Hub | 250W | Not specified | Approx. 30–40 km (144Wh Bosch battery) | Motor (2.6 kg) + Battery (1.3 kg) | 15.5 mph (25 km/h) | Must be fitted at ARCC | Brompton (A Line, C Line, P Line, T Line) | £1,899+ | $2,400+ |
1. Swytch Conversion Kit
The Swytch Kit is a well-known folding bike conversion system that is particularly compatible with Brompton bikes. The kit includes a front motor wheel, a battery pack, and a pedal sensor. Its battery comes in two sizes: the Air Power Pack offers a range of up to 15 km, while the larger Max Power Pack can provide up to 30 km of range. The motor has a power rating of 250W and a torque of 40Nm, ensuring you get a good balance of power and efficiency for city rides. The total weight added by the kit is minimal, with the motor wheel adding about 1.5 kg and the battery weighing 1.1 to 1.5 kg, depending on the version you choose.
The Swytch Bike Kit stands out for its ease of use and impressive power output, particularly on uphill rides. The absence of a dedicated handlebar remote for adjusting power levels is a slight drawback, as the controls are located on the battery itself, making mid-ride adjustments a bit less convenient.
However, the balance between performance and added weight is well-executed, allowing the Brompton to retain its nimbleness while providing solid electric assistance. Setting up the pedal assist sensor may require some fine-tuning to achieve optimal performance, but once configured, the system performs reliably. Overall, the Swytch Bike folding kit offers an affordable and effective way to transform a standard Brompton into an e-bike.
Swytch Bike Folding Kit
| Specification | Details |
|---|---|
| Position | Front Hub |
| Motor Power | 250W |
| Torque | 40 Nm |
| Battery Range | 15 km (Air) or 30 km (Max) |
| Battery Weight | 1.5 kg |
| Total Weight | ~3 kg |
| Charge Time | 3-4 hours |
| Top Speed | 15.5 mph (25 km/h) |
| Installation Time | 30 minutes |
| Compatibility | Folding bikes, including Brompton |
| What’s Included | Front motor wheel, handlebar-mounted battery (Air or Max), pedal sensor, charger, LED display |
| Price | €469 (Pre-Order) |
2. Boost Bike Kit for Brompton
The Boost Bike Kit is a premium, UK-manufactured electric conversion system designed specifically for Brompton folding bikes. It features a 250W rear hub motor and offers sufficient power for urban commuting, with the system providing smooth, responsive assistance, especially during climbs. The battery, discreetly placed between the seat tube and rear frame, stays secure even when the bike is folded without compromising its iconic foldability.
The Samsung battery cells charge fully in just a few hours, and the entire setup adds minimal weight, preserving the Brompton’s lightness and maneuverability. The system adds only 2.5 kg to the bike’s weight, and the motor provides a range of up to 30 km on a single charge. The setup process is straightforward, typically taking less than 20 minutes, and the settings are easily adjusted via the accompanying app.
On the road, the kit’s performance is reliable, with smooth acceleration and stable handling without affecting the original charm and handling of the Brompton. The motor delivers a solid boost, especially for city commuting, while maintaining agility. There is a minor concern about the battery’s power switch, which could be vulnerable in wet conditions, though this doesn’t significantly detract from its overall performance. Optional features include a wireless display and customizable battery colors.
| Specification | Details |
|---|---|
| Position | Rear Hub |
| Motor Power | 250W |
| Torque | Not specified |
| Battery Range | Up to 30 km |
| Battery Weight | 2.5 kg (including motor) |
| Charge Time | 3-4 hours |
| Top Speed | 15.5 mph (25 km/h) |
| Installation Time | Less than 20 minutes |
| Compatibility | Brompton |
| What’s Included | Motorized rear wheel
Battery unit Two sprocket Brompton wheel Charger |
| Price | £995 (approx. $1,250) |
3. Cytronex Brompton Kit
The Cytronex Brompton Kit is highly praised for its lightweight, discreet design, and ease of installation. It’s a popular choice for Brompton owners looking to electrify their bikes without compromising the classic foldable design. The kit uses a 250W front hub motor, paired with a 1.5 kg water-bottle-style battery that integrates the system’s electronics. This design ensures minimal added weight while offering a solid range of up to 40 km per charge, making it an efficient option for city commutes. Charging the battery takes around 3.5 hours, providing a decent turnaround time for daily use.
In practice, the Cytronex kit offers smooth and quiet power delivery, with five customizable assistance levels controlled via a boost button on the handlebars. The system also features a Bluetooth-enabled app, allowing for easy monitoring of battery levels and adjusting power settings. We have noted how intuitive and efficient the system is, especially on urban rides where quick power adjustments are needed. However, one point of feedback is that the system’s power delivery can feel less responsive compared to torque-sensing systems, as the Cytronex relies on cadence sensing, which delivers power in a more on/off manner.
Testing has shown the Cytronex to be reliable under varied conditions, from city streets to more challenging rides on gravel paths. Its durability, combined with the lightweight design, makes it a highly recommended option for Brompton riders who want to maintain the bike’s portability while adding electric assistance. However, the kit is on the pricier side, especially when factoring in professional installation
| Specification | Details |
|---|---|
| Position | Front Hub |
| Motor Power | 250W |
| Torque | Not specified |
| Battery Range | Up to 40 km (25 miles) |
| Battery Weight | 1.5 kg |
| Charge Time | 3.5 hours |
| Top Speed | 15.5 mph (25 km/h) |
| Installation Time | 30–45 minutes (self-fit) |
| Compatibility | Brompton |
| What’s Included | Motorized front wheel
Battery (water-bottle-style casing), Quick-connect bottle cage Boost button Charger Pedal sensor |
| Price | £1,145–£1,200 (approximately $1,250–$1,320) |
4. Byqee F23 Brompton Kit
This conversion kit prioritizes portability, maintaining the lightweight and compact nature of folding bikes, making it especially practical for urban commuters. The F23 kit is compatible with any folding bike that features a 2 or 3-bolt mount on the front handlebar stem, but if the bike lacks this feature, the V23 model serves as a versatile alternative.
A key advantage of the Byqee F23 is its 1.2 kg battery, which stands out as one of the lightest in its category. This battery can be fully charged in just three hours, providing up to 40 km of range on a single charge. For those needing extended range, additional battery packs are available, which can increase the range up to 80 km. The system is powered by a 250W hub motor that is efficient for typical urban terrain and handles moderate inclines with ease.
However, while the motor’s torque performs well for flat city commutes, it may not be as powerful on steeper inclines compared to more expensive conversion kits. Despite this, it still provides a reliable performance in everyday urban environments, balancing power with portability.
The kit’s design allows for easy installation, integrating seamlessly with the folding mechanism of bikes like the Brompton. Optional features like a throttle and extra battery options provide flexibility in personalizing the ride experience, catering to a variety of commuting needs
| Specification | Details |
|---|---|
| Position | Front Hub |
| Motor Power | 250W |
| Torque | 45 Nm |
| Battery Range | Up to 40 km (25 miles) or 80 km (50 miles) with two extra batteries |
| Battery Weight | 2.4 kg (including motor) |
| Charge Time | 3 hours |
| Top Speed | 15.5 mph (25 km/h) |
| Installation Time | 20–30 minutes |
| Compatibility | Brompton, Dahon, Carraro, and Tern (standard 2 or 3-bolt mount) |
| What’s Included | Motorized wheel motor
Battery Mounting bracket Pedal sensor Charger Rain covers |
| Price | €945 (approximately $1,020) |
5. ARCC Brompton Conversion Kit
The ARCC Brompton Conversion Kit is an advanced electric retrofit system for Brompton bikes, designed to maintain the bike’s foldability while adding significant electric assistance. The kit uses a 250W front hub motor powered by Bafang and ARCC’s Intelligent Drive Pod, offering smooth acceleration and power delivery.
One of its standout features is the Bluetooth-controlled power levels and an automatic mode that adjusts assistance based on terrain (7 assist levels). This ensures an easy ride up hills, although some users mention that power reduction on flat terrain is less than expected, potentially affecting battery life. The kit adds around 4 kg to the bike, making it one of the lighter conversion options.
The combination of torque sensors and an inclinometer ensures responsive power delivery, adjusting assistance based on gradient changes. However, in automatic mode, the system tends to use more power on flat terrain than expected, which may slightly impact battery life, though this doesn’t detract from its overall efficiency. The controller is easy to use, though the small buttons can be difficult to operate with gloves. Despite this, the overall build quality and engineering are exceptional
ARCC offers different packages, including a conversion option starting from £1,899 (approx. $2,400), and they also sell fully converted Brompton bikes with the ARCC system installed. The ARCC Brompton Conversion Kit is adaptable across multiple Brompton models, including the A Line, C Line, P Line, and T Line.
| Specification | Details |
|---|---|
| Position | Front Hub |
| Motor Power | 250W |
| Torque | Not specified |
| Battery Range | Approx. 30-40 km (144Wh battery) |
| Battery Weight | 3.9 kg (including motor) |
| Top Speed | 15.5 mph (25 km/h) |
| Charge Time | 3-4 hours |
| Installation | Professional installation required at ARCC’s Cambridge headquarters |
| Compatibility | Brompton, Moulton, Abington or Airnimal |
| What’s Included | Intelligent Drive Pod
Front hub motor Bosch battery Bluetooth handlebar controller Launch control |
| Price | £1,899 (approx. $2,400) |
