Hot air e-bikes carrying large hubs or medium motors and even larger batteries remain the industry standard, but a number of sleeker e-drive products have brought the look and weight of e-bikes closer to those of traditional bicycles. Scottish startup FreeFlow Technologies has pushed the latest lightweight e-drive to market, neatly packing its hardware into the bike’s bottom bracket.

Since its inception in 2012, FreeFlow has worked to develop a scalable electric drive designed to be integrated into e-bikes of various styles during manufacturing. Its goal has been to develop an e-drive with an exceptional power-to-weight ratio, and its current version offers up to 290W of peak power and weighs between 5.5 and 7.7 lbs (2.5 and 3.5kg). The lithium-ion battery adds between 3.3 and 5.5 lbs (1.5 and 2.5 kg), depending on capacity.

Unlike the typical domed mid-drive, the FreeFlow drive integrates more seamlessly with the frame and chainring. Spin the bike around and, while you’ll notice the drive behind the left pedal, it’s not as big and bulky as other mid-motor systems. In addition to the motor, the drive includes patented transmission hardware. FreeFlow says it promotes clean, natural pedaling without the pedaling resistance felt with some electric drive systems.

As for the battery, manufacturers can install it directly inside the downtube or attach it to the outside. A second range extender can also be used with the FreeFlow system.

FreeFlow Technologies

Specifications such as torque and range vary by manufacturer and model, but the FreeFlow drive will offer multiple output modes and assisted speeds up to 15.5 mph (25 km/h). The battery will take between four and five hours to fully charge.

While certainly compact and low-profile, the FreeFlow isn’t the lightest, sleekest e-bike mid-drive on the market. The fully tube-integrated Vivax Assist, which evolved from the Gruber engine but was discontinued in 2020, weighed less than 4.4 lbs (2 kg) with battery and was so compact and imperceptible that it ended up in the heart of controversies over “mechanical doping” involving the ability of professional cyclists to use it to cheat. The similarly in-tube HPS Watt Assist Pro system is built into one of the world’s lightest e-road bikes, the 8.5 kg (18.7 lb) Domestic, but relies on an external battery larger and heavier than the Vivax Assist.

Other systems the FreeFlow Drive will compete with include the lightweight but remarkable 8.8 lb (4 kg) Bikee Lightest, the 7.7 lb (3.5 kg) Maxon Bikedrive Air and the Modular 9, 7 lb (4.4-kg) Ride 50, the latest evolution of the bottom bracket-integrated Fazua drive that previously featured on bikes from Trek and Nox, among others. All weights include the respective batteries.

FreeFlow Technologies

In November 2021, FreeFlow announced its first OEM partner in UK wooden gravel bike builder Twnpa Cycles, which tested a prototype wooden bike with FreeFlow drivetrain. FreeFlow says it has also attracted interest from dozens of other bike manufacturers and is seeing its hardware integrated into everything from mountain bikes to road commuters.

FreeFlow announced on Monday that it is moving into production after raising £1.65 million (about $2.2 million) in its last funding round. We’ll be keeping an eye out for early production bikes equipped with FreeFlow.

Source: FreeFlow Technologies