The Danish company CeramicSpeed has developed what could be the most efficient bicycle powertrain in the world and has built a prototype to prove it.
The manufacturer of bicycle parts is one of the winners of the Eurobike Award last year with Driven, a transmission concept that was developed together with the mechanical engineering department of the University of Colorado.
The Driven drivetrain has no chain or derailleurs, which makes it more efficient at an 99%. This means that almost none of the power generated by the cyclist's legs is lost.
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The powertrain prior to beating was a Shimano Dura-Ace with an efficiency of 97.8 percent, or 98.37 percent when upgraded with CeramicSpeed parts.
The Shimano Dura-Ace, like the motor units on most bicycles, is driven by a chain. While the chains have many advantages, they can also stretch and wear out, especially when the cyclist changes at extreme speeds.
In contrast, the CeramicSpeed system is connected by a carbon fiber shaft, which rotates 90 degrees from the rear wheel and pedals.
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The best of CeramicSpeed Driven
- Chain (and shift pulleys) replaced with drive shaft
- The teeth in the chain ring and the teeth mesh with the ceramic bearings on the shaft
- It has an 49% less friction than the Dura-Ace powertrain
- 32% less friction than the UFO CeramicSpeed chain with large pulleys
At each end of the shaft there are 21 low friction ceramic bearings, which transfer the torque from the cyclist's pedaling through the drive shaft and to the rear gear.
"CeramicSpeed has proudly achieved what many have said can not be done," said Jason Smith, CTO of CeramicSpeed. "We have achieved a multiple speed transmission of the 99 percent while eliminating the chain and the complex rear derailleur."
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They achieved the objective 99% efficiency
CeramicSpeed recently acquired Friction Facts, a Colorado efficiency testing lab, and founder Jason Smith has been busy researching ways to make transmissions as efficient as possible.
"Two and a half years ago we started a project called Pursuit of the 1% Drivetrain," said Smith, now CeramicSpeed's main technology office. "The search was, how can we get an efficient transmission stream to the 99%?"
Smith said that the company had already pushed the envelope with lubrication, bearings and pulleys as far as possible, creating a transmission with an efficiency of approximately 98%, so they had to resort to another system. Based in Boulder, Colorado, Smith partnered with the Department of Mechanical Engineering at the University of Colorado.
"The advances in transmission technology have been evolutionary since the 1920 decade. Driven is truly revolutionary due to its unique rolling element power transfer and unrivaled efficiency "
A prototype in testing phase
The Driven concept has the ability to change the way the cycling industry considers powertrain design and powertrain efficiency.
Axle-driven bicycles have existed since the 19th century, but the concept is changing thanks to CeramicSpeed's research in Colorado.
The CeramicSpeed Driven is a concept, and one with several steps to go before becoming a usable product. For starters, there is still no way to change the system, but Smith says that a wireless servo could be installed inside the shaft to move it forward and backward in the cassette.
You could also install a power inside the shaft, with a measurement system similar to the operation of a PowerTap bushing, measuring the torsional deviation in the cylinder.
Driven is in the prototype phase. CeramicSpeed exhibited the invention at the Eurobike fair in Germany from 8 to 10 in July last year.
The company has filed a patent application while conducting more tests. Currently, it has only tested Driven at 100 watts, with the efficiency figures extrapolated to a higher user output, where it should reach the 99% efficiency.
While this small improvement in efficiency is of the utmost importance to cyclists, CeramicSpeed says it provides a wide range of applications, such as track, triathlon and electric bicycles.
Do you think that it will become a product that will evolve the bicycle market? Will the UCI allow this system in the most important cycling races?