The “FSA System” comprises of a rear hub electric-assist motor, a total of 500Wh (250Wh battery unit + 250Wh RE) with an integrated onbike control unit and smartphone app. FSA System’s compact design and low weight (a full system weighs just 3,98kg) ensures sleek integration for e-road, e-gravel, and commuter bikes. With a 20-cell, 250Wh battery unit that integrates completely inside the downtube, and an additional 250Wh battery installable within a bottle cage for longer rides, the system has a flexible range to suit all types of riders. The system is completed with a LED HID push button that integrates into the top tube and an easily accessible charge port situated above the bottom bracket. There are five assistance settings, 1 neutral, 4 active, while the motor itself features an integrated torque sensor and speed sensors, which can adapt easily to different riding styles and changing conditions. Not only does it provide extremely responsive yet consistent assistance, it is quiet, outputting less than 55 decibels. When exceeding the EU-mandated limit of 25km/h for electrical assistance (32km/h for the USA), the “FSA System” hub shuts down and presents minimal friction and resistance to the drivetrain, allowing the rider to experience a natural and free pedaling motion. Together with the low total weight and compact integration of the system, the use of standard cranks allows the e-bike to fit like a standard bike and handle as close to an ordinary pedal-powered bike as possible. The compact design also can fit down to XS sized bike frames and all geometries.