Editorial assessment
With the Hub Line Motor, Bosch now also has a product on offer for lightweight urban bikes. The technical specifications look solid: 45 Nm is more than enough for flat to gently undulating terrain, and the 2.3 kg is acceptable, even if some other hub motors are even lighter. It will be interesting to see how the system fares in practice against established hub motor suppliers such as Mahle or Bafang. However, with its infrastructure and service, Bosch is certainly well placed to make its mark in the hub motor market too.
A change of strategy at Bosch
For years, Bosch has been synonymous with powerful mid-mounted engines offering high torque and a sporty character such as the Bosch CX (reviewed here). With the launch of the new Hub Line, the company is now breaking new ground and, for the first time, is also targeting the growing market for urban e-bikes, which are set to appeal with their sleek design and reduced weight.
Bosch Hub Line: The facts
The new in-hub motor has the following specifications:
- Max. torque: 45 Nm
- Max. power: 400 watts
- Weight: approx. 2.3 kg
- Diameter: approx. 100 mm
- Housing: black aluminium
- Special feature: complete decoupling at speeds above 25 km/h
- Integration: fully integrated into the Bosch Smart System
The PowerTube 360, which has also just been launched, serves as the energy storage unit; it is particularly slim and lightweight and is designed to enable clean e-bike designs. Unlike the Compact Tube 400 with its plastic casing, which was introduced with the Bosch SX, the PowerTube 360 features an aluminium casing, but has a slightly lower capacity for the same weight. Bosch states that the range of the Hub Line and the 360 battery is approximately 89 kilometres in Eco mode – sufficient for typical urban usage patterns. As part of the smart system, manufacturers will likely also be able to combine the Hub Line with larger batteries.
Hub motor vs. mid-drive motor: a comparison of the two designs
Why does Bosch offer a hub motor at all? Mid-drive motors are considered to be more dynamic and technically superior. However, hub motors can also have their advantages, particularly on lightweight urban bikes. They are often cheaper and quieter. The motor’s power is not transmitted via the chain, which helps to reduce wear and tear. On single-speed e-bikes with heavy gears, hub motors therefore often provide better acceleration at low speeds. We’ve summarised the pros and cons of this design for you here.
Advantages:
- Quieter operation
- Often cheaper to buy
- Minimalist design is possible
- No additional strain on the drivetrain (chain, sprocket)
- Reduced wear on drive components
- Easier starting with a single-speed bike
Disadvantages:
- A less sporty and direct driving experience
- May make maintenance more difficult (changing hoses, broken spokes)
- Higher unsprung weight
- Limited circuit compatibility
Bosch addresses some of these drawbacks with smart sensor technology for responsive control and complete decoupling above 25 km/h, which is designed to allow riders to cross the assistance threshold with virtually no resistance.
The systems-based approach will continue
The Hub Line is fully integrated into the Bosch Smart System and is complemented by a number of other new features:
- ConnectModule (new generation): more accurate tracking and anti-theft protection
- LED controller: compact handlebar control unit with coloured LEDs
- Intuvia 200: a slim and presumably affordable display with improved readability and a more premium look
Availability: The Bosch Hub Line in-hub motor is expected to appear in the first production bikes from 2027.
Adrian Kaether
Editor
