TechnologyCycling

CeramicSpeed’s Driven concept could change cycling forever

© CeramicSpeed
Written by Phil Barker
Say goodbye to your bike’s conventional chain, as CeramicSpeed come up with a cleaner, faster and more efficient bicycle drivechain of the future.
The latest bicycles feature the sort of materials we see in movies; they weigh less than ever before and once again we’re seeing companies pushing the boundaries of technology. Despite all that, though, the majority of bikes still use the same propulsion system as their counterparts from more than 100 years ago.
The humble chain has been around almost as long as the bike, but its days could be numbered if CeramicSpeed get their way. They want to replace dirty, greasy and inefficient linkages with their innovative Driven concept; a bike which ditches the chain and traditional gearset altogether, turning instead to a driveshaft arrangement. We’ve been talking to Ben Powell, CMO at CeramicSpeed to find out more.
Using a chain to transmit power to the rear wheel may be popular, but it’s not without issues. Powell explains: “Friction is created when the chain articulates into or out of a ring, cog, or pulley wheel under tension. Each time a chain link articulates, the sliding surfaces (pins, bushings, plate shoulders) within the chain consume rider energy.
“In a typical multi-speed drivetrain using a rear derailleur, each chain link will articulate eight times as it goes through one complete revolution. It may seem insignificant, yet consider a chain has over 100 individual links bending back and forth as it snakes through the drivetrain, as the rider is spinning at 90+ RPM.”
That’s over 40,000 chain articulations every minute, adds Powell, and that’s also before we take alignment into account, where cross-chaining (using the outer front gears alongside the inner rear gears, or vice versa, where the chain sits at an odd angle) can almost double the friction a rider encounters.
A photo of the CeramicSpeed Driven drivetrain.
Say goodbye to the rear cassette

Creating a solution

There’s plenty of scope for improvement, and that’s where CeramicSpeed’s Driven drivetrain comes in. They're already renowned for making more efficient bike components, including oversized pulley wheels, bottom brackets and wheel bearings, but an internal project in 2017 saw CeramicSpeed working on creating the most efficient bike yet. The project, dubbed Pursuit of the One Percent Drivetrain, aimed to create a bike drivetrain boasting 99 percent efficiency, losing just one percent of the rider’s power to friction. It was clear that CeramicSpeed would need something special, and a collaboration with the Mechanical Engineering Department at the University of Colorado would provide the opportunity to come up with something truly different.
Not content with redesigning the chain for Driven, CeramicSpeed also ditched the front and rear derailleurs and reworked the gears themselves. In place of a cassette, with a series of cogs stacked on top of each other, CeramicSpeed switched to a design where the cogs sit in line, increasing in size, with a driveshaft connecting the front and rear assemblies.
The result is far smoother than a conventional set-up, says Powell, since the bearing pinions on the end of the driveshaft roll through the cog teeth to provide drive. “Compare this to a chain drivetrain – the chainrings and cogs are not perfect circles; they're actually polygons [multi-sided shapes]. Because of this, the linear speed of the chain entering and exiting the cog is not constant. The chain accelerates and decelerates as it wraps around each ‘side’ of the polygon, or in other words, with each tooth on the cog. Driven, with its flowing bearing and tooth interactions, doesn't exhibit chordal action.”
Along with being more efficient, Powell points out that Driven also ushers in a host of other benefits. It’s less complex, for starters, with fewer components. That also means it’s more compact and lightweight, and can easily be protected against rain, mud and other detrimental conditions. The way the gears are stacked also allow the number of gears to be determined by the diameter of the rear cog itself, and not the width of your bike’s forks, potentially allowing for a greater choice of gears.
A photo of the CeramicSpeed Driven drivetrain.
No more oily chain

Redesigning the chain for everybody

According to Powell, the racing market is most likely to adopt the Driven system first, but professional bike riders on road bikes aren’t the only ones in CeramicSpeed’s sights. New technology is often developed in the racing world, says Powell, before ultimately trickling down to everyday users. “We feel this might be the case with Driven. It could one day be on every bike; city, urban, commuter, off-road, road and triathlon, time will tell.
“It could easily be the future of drivetrains,” adds Powell. “Besides being more efficient, lighter, less complex, and the other benefits described above, if the Driven system were produced in the same numbers as traditional rear derailleur systems, the overall material cost would be lower. Think about it: no chains with 400 individual parts each. No rear derailleur with lots of moving parts. No cassette with 12 or 13-layers deep of cogs. Instead, a bike would have a one-piece shaft, one piece pinions with bearings, and a flat multi-speed rear cog. Yes, the hollow shaft would house the wireless shifting electronics and linear screw for shifting, yet it’s much less complex than the traditional rear derailleur.”
Cheaper, faster, lighter and no more grit and dirt-packed chains to deal with? Sounds good to us.