Last year CeramicSpeed stole the show at Eurobike with their Driven drivetrain that was claimed to be 99% efficient and a serious improvement over derailleur offerings. Of course, our first question was, "Yeah, but will it ever work on a mountain bike?" Last year, Ceramicspeed said it could.... but only if it was a hardtail... and only if it was a singlespeed. Last year's prototype was more about making the most efficient drivetrain possible rather than having one that shifted and it certainly couldn't have coped with the axle paths and changing chainstay lengths of a full-suspension mountain bike
This year they're back with a solution though, a telescoping, rotating version of the drivetrain that they claim works with full suspension mountain bikes. This version still doesn't shift yet but CeramicSpeed did have a prototype version on a road bike that did shift. Combine the two together and the Driven mountain bike drivetrain is a step closer to reality.
So what's going on here? Designed in conjunction with University of Colorado Boulder’s Mechanical Engineering Department, the Driven doesn't look too dissimilar from a standard drivetrain, the cassette and chainring are in the same place you'd expect, albeit with their teeth perpendicular to a traditional setup. The big difference is the carbon-fiber driveshaft with a roller pinion on each end that engages those teeth.
The version at Eurobike this year was designed to allow mountain bikers to use this tech as well. To do this, CeramicSpeed added a telescoping element inside the prototype and allow the driveshaft to rotate via a spherical bearing tucked behind the chainring. There's a video of it in action here:
But the key difference between mountain bikers and road bikers is that on the whole, we don't really care about the minimal gain a more efficient drivetrain could offer, especially when it comes at the expense of the tried and tested derailleur. But CeramicSpeed claim there are some other benefits here too. They believe the driveshaft could be used to lock out the bike's rear end, meaning that a lockout would not have to be squashed into a shock, which may open up development opportunities there. The drivetrain also does not suffer from chain forces that affect suspension action, which could make a bike that uses this drivetrain more supple. Finally, the lack of a derailleur moves weight away from the wheel and into the frame, reducing unsprung weight. CermaicSpeed described it as having the benefits of a gearbox with none of the drag that comes along with it.
At the moment this is a very early concept and it was certainly nowhere near production. The shaft could only travel a small distance but CeramicSpeed claimed that there was theoretically no travel length that would be too long. The main drawback here is that the system will only work on a bike where the pivot is above the axle, on something like a Horst link bike this simply wouldn't be possible. CeramicSpeed and Canyon also had to redesign the rear triangle of the bike to make the system fit, something that would have to be considered on most bikes if the product ever came to market.
CeramicSpeed are very keen to stress this is an early proof of concept and is still lightyears away from production but for us, it's a great piece of engineering and an interesting look into a potential future of mountain bikes.