Genius: This Is How Those Groundbreaking ‘Chainless’ Bicycles Work
31 Jul,2018
Chainless bicycles?
That’s – wait for it – off the chain. *Ba dum tss!*
Seriously, though, when you think about it, it’s pretty damn clever – not so much the pun, but the idea that you can ride a bike without chains.
As cyclists will tell you, a dodgy chain can make them skip between gears and cause intense slippage, which can make for a nightmare ride.
Now cyclists can thank their lucky stars that a company out there has taken the chain out of the equation, and has replaced it with a drive shaft and ceramic bearings, reports Cycling News:
CeramicSpeed and Friction Facts have made a business of reducing friction to an absolute minimum, whether with ceramic bearings or oversized pulleys or highly specialized [sic] chain lube …
CeramicSpeed recently acquired Friction Facts, a Colorado efficiency test lab, and founder Jason Smith has since been busy researching ways to make drivetrains as efficient as possible.
“A year and a half ago we started a project called Pursuit of the 1% Drivetrain,” said Smith, now CeramicSpeed’s chief technology office. “The quest was, how can we get a 99% efficient drivetrain?”
The lightbulb moment arrived once Smith teamed up with the folks at the University of Colorado’s Mechanical Engineering Department. He said:
The shaft concept came up right away – it is just one moving part instead of the many moving parts on a chain and pulleys. The concept has been around forever, but with bevel gears, which have a ton of friction. So we set out to make the shaft drive better than a bevel gear. That’s how we came up with roller element.
In the DrivEn system, those eight points are replaced by four points, each of which rotate on ceramic bearings. The chain ring’s teeth and cassette’s cog engage with the bearings on the shaft, which itself spins on bearings.
Smith says this system creates 49% less friction than a Shimano Dura-Ace drivetrain at 250w. The DrivEn system decreases in efficiency above 380w.