this new bike gear set, CeramicSpeed’s Driven concept drivetrain, grabs attention with its radical looks, and the even more radical claim of better-than-99-percent efficiency.

a carbon fiber drive shaft with a roller pinion on each end engaging toothed cogs. The front cog looks like a chaining with its teeth bent 90-degrees, with a 13-speed rear cog

According to CeramicSpeed’s testing, that best-case chain and derailleur drivetrain is Shimano’s Dura Ace enhanced with CeramicSpeed’s Oversized Pulley Wheel System (OSPW), and the company’s UFO chain which returned about 98-percent efficiency (averaged across all gear combinations). A stock Dura Ace drivetrain returned about 97-percent efficiency.

According to the information provided by CeramicSpeed, 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.

The efficiency gain comes from eliminating a chain and derailleur’s eight points of sliding friction. Driven has, "two points of higher-efficiency bearing roller friction," according to the materials provided by CeramicSpeed’s representatives.

There’s reason the chain and derailleur has endured as the dominant multi-speed bicycle drivetrain system: it’s really good. It's light, it’s efficient, it’s pretty simple, it’s durable, and it’s adaptable to a wide range of uses. Many people have tried to improve this particular mousetrap, and most of them have failed. Time will tell if Ceramic Speed has succeeded in finding the answer that has eluded many others for so long.

https://www.bicycling.com/bikes-gear/a22092182/ceramicspeeds-driven-concept-might-become-the-worlds-most-efficient-drivetrain/