Building a bicycle that weighs only 6 to 7 kg is not the easiest task in the world. Now, imagine a bike that, in addition to weighing 6.872 kg, still has an electric-assisted pedal system! This is the case with Freicycle, developed by German mechanical engineer Dr. Dennis Freiburg.
The former employee of the Institute for Machining Production (ISF) at TU Dortmund University has officially received the certificate for the world record for the lightest e-bike in the world. The record was officially confirmed by GUINNESS WORLD RECORDS under the title “The lightest electric bicycle prototype.”
The Freicycle was built around the ultra-light carbon frame, manufactured by the German high-end bicycle manufacturer Merida and provided by Freiburg.
Anyone who thinks that power was saved in the Freicycle prototype just to achieve the weight is wrong. The drive can do significantly more than the prescribed 250 watts and was only throttled due to the legal situation. Of course, the battery is smaller than that of conventional electric bikes, but here, too, there was a fixed specification from the Guinness World Records.
The electric motor is actually intended for remote-controlled model helicopters and is attached under the frame with a specially made bracket. The motor is software-restricted to an EU-legal power (250 watts) and 25-km/h (15.5-mph) of maximum speed. But when unlocked, it is capable of supporting the cyclist with up to 600 watts of power and reaching speeds up to 48 km/h (30 mph).
The motor transfers its power to the rear wheel casing with a roller. Besides, the Freicycle comes equipped with lightweight sensors on the rear wheel to transmit speed data to the electronic control of the wheel.
The inside has been worked up in such a way that Freiburg was able to place the control electronics and 137-Wh battery in a lightweight, off-the-shelf drink bottle. The engineer created the new lid for the bottle and other components – for example, the bottle holder – in a 3D printer. Depending on the level of support, a range of 19-35 km (12-22 miles) is possible. For a longer range, an extra battery can easily be installed.
In addition, the bike bets on high-end components, such as the SRAM Red transmission, Dura-Ace horseshoe brakes. The entire propulsion system weighs only 2kg.
The development of the bike for the e-bike record was, of course, not that easy: the designer Freiburg mobilized a lot of knowledge and support from colleagues in order to bring the ultralight model to the road.
