Bicycles

The recipe for the Freicycle, the world's lightest ebike

The recipe for the Freicycle, ...
The Guinness World Record for the world's lightest prototype ebike is held by the 6.872-kg Freicycle
The Guinness World Record for the world's lightest prototype ebike is held by the 6.872-kg Freicycle
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The Freicycle started out as a Merida Scultura ultra-lightweight climbing bike
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The Freicycle started out as a Merida Scultura ultra-lightweight climbing bike
Dr. Dennis Freiburg with his world-record-holding Freicycle
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Dr. Dennis Freiburg with his world-record-holding Freicycle
The miniature friction drive is capable of delivering up to 600 watts
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The miniature friction drive is capable of delivering up to 600 watts
The battery's in the drink bottle, which rocks a 3D-printed cap that also serves as a power switch and assist level dial
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The battery's in the drink bottle, which rocks a 3D-printed cap that also serves as a power switch and assist level dial
The Guinness World Record for the world's lightest prototype ebike is held by the 6.872-kg Freicycle
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The Guinness World Record for the world's lightest prototype ebike is held by the 6.872-kg Freicycle
The Freicycle delivers up to 35 km of pedal-assist riding
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The Freicycle delivers up to 35 km of pedal-assist riding
The tiny motor comes from the main rotor of a radio controlled helicopter and has been converted into a friction drive
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The tiny motor comes from the main rotor of a radio controlled helicopter and has been converted into a friction drive
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In December 2019, Germany's Dr. Dennis Freiburg, mechanical engineer, stamped his name into the Guinness Book of World Records with the world's lightest ebike: the 6.872-kg (15.15-lb) Freicycle. Now, he's revealed how he did it – with a 600-watt friction drive motor.

The Freicycle started out as a 2016-model Merida Scultura – a carbon-framed climbing racer with a sub-1kg (2.2-lb) frame and rim-mounted brakes to cut down on weight as much as possible. Freiburg took things up a notch with a full carbon crank and 3D-printed pedals, and barely-there carbon rims. Every metal part was assessed to see if it could be replaced by something lighter and 3D printed, and the brake calipers were one example of something that was tossed for a lighter, 3D-printed design.

The motor and battery typically add a lot of weight to an ebike build, and here Freiburg got a little creative. Instead of a hub or mid-mounted drive motor, he took the small motor powering the main rotor of a model helicopter and fashioned it into a friction drive that rests against the rear wheel under power, and swings out of the way when it's not in use.

The tiny motor comes from the main rotor of a radio controlled helicopter and has been converted into a friction drive
The tiny motor comes from the main rotor of a radio controlled helicopter and has been converted into a friction drive

The motor is software-restricted to an EU-legal 250 W and 25-km/h (15.5-mph) maximum pedal assist speed, but when unlocked it can deliver as much as 600 W and push the bike to speeds up to 48 km/h (30 mph). Even in restricted mode, the Freicycle's ludicrously low weight makes it much easier to ride fast in an unassisted fashion than most ebikes, and the tiny motor adds no pedal drag when it's not touching the wheel.

To carry the Guinness-mandated minimum 137-Wh battery, Freiburg grabbed a lightweight, off-the shelf drink bottle, filled it up with batteries and control electronics, made a 3D-printed bottle holder, and wired the whole thing up to that. He 3D printed a new lid for the bottle that's also capable of acting as an on/off switch for the bike and an assistance level dial as well. Lightweight sensors in the crank and wheel provide the system with information on the wheel speed and pedal cadence.

The entire drive system weighs less than 2 kg (4.4 lb), and the battery is sufficient for a range between 19-35 km (12-22 mi). Freiburg says it's not too much of a pain to carry an extra drink bottle battery pack if he needs a little extra range.

The Freicycle delivers up to 35 km of pedal-assist riding
The Freicycle delivers up to 35 km of pedal-assist riding

The bike is just 72 g (2.54 oz) over the 6.8-kg (15-lb) minimum weight required by the UCI organization for international race events – although there are a fair few people pushing to have that minimum weight lowered or eliminated.

The project as a whole cost somewhere around €20,000 (US$23,790) to realize, which is a lot for a bike, but not a lot for a Guinness World Record. If you're looking for the lightest ebike you can actually buy, the lightest we can find is the 11-kg (24.3-lb) Invisitron R1, which rocks a 250-W motor and costs AU$3,300 (US$2,380) – and that's a much easier price tag to come at.

See the Freicycle in action in the video below:

LIGHTEST E BIKE in the WORLD Showreel – Guinness World Record

Source: Freicycle

View gallery - 7 images
6 comments
PAV
15.5 lbs is lighter than most regular bikes. That friction motor is genius, I wonder how it gets engaged/disengaged. I like that the bike free wheels when the motor is disengaged.
Ligfietser
Sorry, but I am not impressed, as you can actually buy in Germany the “Velospeeder” The lightest set of the Velospeeder weighs 1.6kg. here:
http://www.velogical-engineering.com/velogical-velospeeder---standard-motor-for-bicycles-retrofittable.
Also one can buy from Austria a similar friction drive, that weighs also 2.2kg, the brand is called “add-e”, with long time
Ligfietser
sorry apparently I touch some wrong button on my iPad. I was not finished with the “add-e” electric bicycle motor. Here is the link:
https://www.add-e.at/?lang=en
Enjoy!
Gannet
Velospeeder already mentioned here. Looks to be a quality product.
Grunchy
Pretty darn good!
T N Args
These motors are not new on ecycles, especially from RC planes, and the big issue is the contact point with the tyre: either it slips too easily and you get no traction when you need it most, or you use grit (or similar surface) and strip the wearing surface off the tyre in no time.

I like these motors as a lightweight solution, but what you need is a rim with a special profile that has a cantilever sticking out one side with a cogged or corrugated surface. Then drive this with a carbon belt from the RC aero motor. Refine the design for minimum weight, and I'm sure the few extra grams will be worth it for the practicality advantage over the friction drive's issues.