CeramicSpeed has a demo bicycle drive-train, dubbed Driven, that uses a drive shaft instead of a chain and they’re showing it off at Eurobike 2018. The concept not only sports some radical looks, but comes with an even more radical claim of better-than-99-percent efficiency.
As Driven is only a concept drivetrain, there are a lot of unanswered questions like, “Will it be strong enough to withstand a sprint?” and, “What happens when I fall into that meat-grinder looking cassette?” Along with many others.
We probably won’t be getting a lot of answers anytime soon. The main motivation behind Driven was to create a drivetrain that only had one-percent frictional losses. After multiple attempts, the most promising was a carbon fiber drive shaft with a roller pinion on each end engaging toothed cogs. The front cog looks like a standard chaining with its teeth bent in at 90-degrees. The 13-speed rear cassette looks a bit more menacing with its outward facing teeth. Altogether, the system shows better-than 99-percent efficiency.
According to CeramicSpeed’s testing, a modern best case scenario drive-train is Shimano’s Dura Ace enhanced with CeramicSpeed’s Oversized Pulley Wheel System (OSPW), and the company’s UFO chain which returns about 98-percent efficiency. A stock Dura Ace drivetrain nets about 97-percent efficiency. This means that Driven has 32-percent less friction than the CeramicSpeed enhanced drivetrain, and 49-percent less friction than the stock Dura Ace drivetrain.
Probably doesn’t mean a whole lot to weekend warriors, but pros would kill for a few percentage points.
CeramicSpeed definitely have their work cut out for them. There’s reason the chain and derailleur are the mainstays of the multi-speed bicycle drivetrain system: it works. It’s fairly light, it’s pretty efficient, it’s simple and it’s durable. Many have tried to improve the drivetrain, and many have failed.
Here’s a CeramicSpeed rep explaining the drivetrain in more details: