15-lb electric bicycle sets a world record and pushes the limits of e-bike construction

FlatSix911

Well-Known Member
An interesting article from Electrek... the weight weenies will love this Ebike! ;)

Truly an amazing engineering feat to design and build this as a DIY Ph.D. project.


We’ve seen lightweight e-bikes before, but none have ever approached the 15.15-lb (6.872 kg) Freicycle electric bike built by mechanical engineer Dennis Freiburg. His featherweight e-bike recently set a new Guinness World Record for the Lightest Electric Bicycle – Prototype. The Freicycle took Freiburg the better part of a year to design and build, serving as part of a project for his doctoral degree.

Built on a carbon Merida Scultura road bike, the Freicycle benefited from the start with an ultralightweight frame weighing less than 2.2 lb (1 kg). Freiburg kept the rest of the weight down with as much carbon fiber as possible for critical load-bearing components such as the wheels, fork, and cranks. Other components that couldn’t be sourced light enough were 3D-printed, such as special ultralight pedals.


 

Art Deco

Well-Known Member
An interesting article from Electrek... the weight weenies will love this Ebike! ;)

Truly an amazing engineering feat to design and build this as a DIY Ph.D. project.


We’ve seen lightweight e-bikes before, but none have ever approached the 15.15-lb (6.872 kg) Freicycle electric bike built by mechanical engineer Dennis Freiburg. His featherweight e-bike recently set a new Guinness World Record for the Lightest Electric Bicycle – Prototype. The Freicycle took Freiburg the better part of a year to design and build, serving as part of a project for his doctoral degree.

Built on a carbon Merida Scultura road bike, the Freicycle benefited from the start with an ultralightweight frame weighing less than 2.2 lb (1 kg). Freiburg kept the rest of the weight down with as much carbon fiber as possible for critical load-bearing components such as the wheels, fork, and cranks. Other components that couldn’t be sourced light enough were 3D-printed, such as special ultralight pedals.


Wow. A friction drive. 🤔
 

FlatSix911

Well-Known Member
Wow. A friction drive. 🤔

An interesting choice for sure... looks like a tiny hamster wheel. ;)

For the motor, Dennis relied on a decidedly low-tech but lightweight solution: a friction drive. Lightweight hub motors and mid-drive motor exist, but they can’t compare to the minimalism of a properly-designed friction drive. These types of e-bike drives have been around for decades due to their simplicity. A powered roller is pressed against the bicycle tire, requiring minimal mounting and zero gearing.

Freiburg used a brushless RC helicopter motor capable of putting out 600 watts of power, wrapped in an abrasive sleeve to provide grip to the rear tire. The torque of the motor causes its simple mount to swing down and engage the rear tire. When the motor’s power is cut, the spring-loaded mechanism pulls it back out of the way of the tire. Simple. Effective. Light.

Since the Freicycle was built in Europe, the motor is limited to a street-legal 250 W and a top speed of 15.5 mph (25 km/h).
But when unlimited, the Freicycle can apparently reach speeds of up to 30 mph (48 km/h) with its full 600 W of power.


freicycle
 
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fooferdoggie

Well-Known Member
An interesting choice for sure... looks like a tiny hamster wheel. ;)

For the motor, Dennis relied on a decidedly low-tech but lightweight solution: a friction drive. Lightweight hub motors and mid-drive motor exist, but they can’t compare to the minimalism of a properly-designed friction drive. These types of e-bike drives have been around for decades due to their simplicity. A powered roller is pressed against the bicycle tire, requiring minimal mounting and zero gearing.

Freiburg used a brushless RC helicopter motor capable of putting out 600 watts of power, wrapped in an abrasive sleeve to provide grip to the rear tire. The torque of the motor causes its simple mount to swing down and engage the rear tire. When the motor’s power is cut, the spring-loaded mechanism pulls it back out of the way of the tire. Simple. Effective. Light.



Since the Freicycle was built in Europe, the motor is limited to a street-legal 250 W and a top speed of 15.5 mph (25 km/h). But when unlimited, the Freicycle can apparently reach speeds of up to 30 mph (48 km/h) with its full 600 W of power.
not sure how many miles you will get out of the motor rc helis not built for years of flying maybe months before i destroyed one (G) but better not use it in the rain.
 

Deacon Blues

Well-Known Member
I can't believe this ebike is 2.5 pounds lighter than my carbon Giant Defy Advance Pro 0. :p

It may not be practical, but it sure is cool. 👍
 

Art Deco

Well-Known Member
I'm imagining just how fast a strong rider can go on that bike...really could knock down long commutes and outrun most traffic...:oops:... but the battery might outlast the tire.
 
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FlatSix911

Well-Known Member
I got my carbon road bike down to 14.36 lbs by replacing every fastener with Titanium... even the pedal spindles and stem bolts. ;)
 
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FlatSix911

Well-Known Member
I found an old photo of my bike on the scale... just under the UCI race limit by 0.6 lbs.


Now I am a reformed weight weenie and love riding a 41 lb Ebike! ;)

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