The design of the traditional bicycle drivechain has been static for a very long time, but CeramicSpeed has just introduced a major shift in drivechain technology with their new DrivEn system, which just won a Eurobike Design Award at the major tradeshow in Germany.
CeramicSpeed, and recently acquired Friction Facts, a Colorado efficiency test lab have made a name for themselves by creating products that take drivechain friction to an absolute minimum, whether with ceramic bearings, oversized derailleur pulleys, or highly efficient chain lube. While those projects all made an impact, the company is taking a giant step forward with the DrivEn drive shaft concept.
The DrivEn system replaces the standard 8 points of chain sliding friction, two rear derailleur pulleys, and cross chaining with a mere two points of bearing rolling resistance. The sliding friction from a traditional system is eliminated as power transfer occurs through ceramic bearing-tipped lobes on the front and rear pinions. In testing, the DrivEn systems created 49% less friction than a stock Dura Ace drivetrain at 250W rider output.
The system, which was developed in cooperation with the mechanical engineering department at the University of Colorado in Boulder, uses a novel shaft-drive design that the company says eliminates sliding friction almost entirely. The efficiency of the DrivEn system hits a claimed 99% at 380W rider output.
The DrivEn reportedly bests even a CeramicSpeed-optimized Dura-Ace drivetrain with an oversized pulley wheel system and UFO racing chain by creating 32% less friction than the fully optimized system at a 250-watt rider output.
Friction numbers measured with the prototype system saw overall efficiency of DrivEn increases slightly as rider power output increases. CeramicSpeed also has several enhancements in the works that will increase efficiency even further, such as double row ball bearings and a more-optimized tooth shape and angles.