Bosch’s Performance SX Motor Hits the Market

Bosch recently launched its brand new lightweight e-bike motor, the Bosch Performance SX. Discover how this lightweight, powerful, and highly responsive motor revolutionizes the world of lightweight e-bikes.
Alex Boyce
Written by Alex Boyce
E-Bike Reviewer
robb dorr
Edited by Robb Dorr

This motor is aimed at lightweight e-bikes either, eMTB, Gravel, or Urban. The idea is to give bike makers the ability to use the preferred components from the Bosch Smart System and build e-bikes that are more maneuverable and responsive, benefiting the end user through a total battery and motor weight of only 4 kilos compared to the almost 8 kilos of a normal heavyweight e-bike motor and battery system.

Bosch Performance SX Motor Specifications

Motor2024 Performance SX
Weight4.41 lbs (2 kg)
Power250W (600w peak over 100 RPM)
Torque55 Nm
Battery400 Wh (2 kg weight)
External Extra Battery 250 Wh
RemoteMini Remote
DisplayToptube display or Bosch Kioxx 300 / 500 (new bigger screen)

These numbers reflect a motor that is not the lightest but is the most powerful. Bosch also encouraged us to think about the peak power rating more than the torque rating, which does not necessarily give a clear idea of the actual on-bike performance.

The battery uses the latest 21700 cells which gives the highest power density of any battery on the market at 200 Wh/kg. This battery can be also used with a brand-new external battery from Bosch with 250 Wh of capacity. The two batteries drain in parallel maintaining a more constant voltage and support for the motor. This extender battery can also be used with the other batteries in the smart system range.

The new system can be fully tuned from the Flow app which also allows navigation and other data to be displayed.

The gravel motor variant also has a new sprint mode to support out-of-the-saddle uphill sprinting.

Performance SX On the Trail

We managed only one hour ride with one descent and climb. This gave us enough time to recognize the characteristics of the motor, but not enough time to assess the range the motor provides.

It’s very smooth with an incredibly well-balanced use of power. Noise levels are lower than the full-power motor. This motor feels like a Bosch motor. Extended boost is present and it works. Pump the pedals and the motor will give a short overrun propelling the bike over any trail feature. To get full power you must use a higher cadence and more pedal control. The outcome is that it is possible to ride with a full-power e-bike rider at the same speed uphill.

The motor’s full turbo mode and fully tuned option leave no desire for more power in the rider.

Adding this system to your bike reduces its weight by about 8 lbs (4 kg). You can immediately feel this on the trail when riding downhill as the bike can be jumped around effortlessly, and it is swifter to change direction and easier to brake with less dive.

We preferred Turbo and eMTB modes the most, with Eco mode feeling like a normal bike.

On technical climbs, the assistance was constant, and with an extended boost, we got through some tricky sections without stress or stopping.

Final Thoughts

After a short test, it’s not easy to come to any complete conclusions, but we feel that the Bosch Performance SX motor, on first impressions, is the best lightweight motor on the market for power delivery and sustained output in this category.

It feels like a Bosch motor, rides like a Bosch motor, and has given bike makers a ton of options if they want to use the smart-system components to make an advanced up-to-date motor.

We will have more details on this system soon after testing a production bike and more time on our local trails. Getting the most out of your eMTB is crucial.

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About Our Editorial Team

Alex Boyce
Written by Alex Boyce
E-Bike Reviewer
Alex Boyce has been in the bike industry in various roles since 2008, he has tested more than 400 bikes over the years and created content for magazines and media outlets the world over.
robb dorr
Edited by Robb Dorr
Robb is a massive cycling enthusiast who has more than 20 years of non-motorized cycling experience. He started to lower the barrier of entry to cycling and reduce the intimidation people can experience when getting into the cycling world.

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