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by Dave Rome
August 27, 2019
Photography by CeramicSpeed
Do you remember CeramicSpeed’s shaft-drive drivetrain that was unveiled at last year’s Eurobike trade show? The Driven drivetrain that claimed to be 99% efficient by all but eliminating the sliding friction losses that are present in chain-driven drivetrains? Well, it seems CeramicSpeed hasn’t slowed its development process, and the latest news from the company is that the Driven drivetrain offers aero benefits, too.
Tested in collaboration with Specialized and on that company’s Venge platform, the Driven-equipped concept bike showed a 3% aerodynamic improvement over a regular Venge (with 53/39T gearing) across all yaw angles. Ingmar Jungnickel, Specialized’s Aerodynamics R&D Lead, suggests that the Driven drivetrain could save as much as eight seconds over 40km, a similar saving to what the current generation Venge offers over the Venge ViAS.
CeramicSpeed’s Driven drivetrain concept uses a carbon fibre driveshaft. The ends are fitted with two circular pinion arrays topped with a series of smaller cartridge bearings.
“When we first embarked on the pursuit of the 1% drivetrain initiative, the Product Engineering and Design team’s focus was to achieve the utmost level of mechanical efficiency, yet aerodynamic efficiency was always in the back of our mind,” said Jason Smith, CeramicSpeed’s Chief Technology Officer of the Driven drivetrain concept. “During the early phases of development, it became pretty clear that Driven might very well turn out to be the most aerodynamically efficient drivetrain. But speculation means nothing without quantitative testing.
“Thanks to the rigorous aero testing at Specialized’s Win Tunnel, it has been proven that significant aerodynamic gains can be captured with Driven. It is quite an incredible R&D accomplishment to achieve the most efficient bicycle drivetrain ever developed … both mechanically and aerodynamically”
According to Ingmar Jungnickel, the Driven drivetrain offers aero benefits without being aerodynamically designed, and further improvements could still be made.
Efficient and aerodynamic it may be, but the prototype shown at last year’s Eurobike show was far from a rideable solution. There were big question marks over the strength and ability to change gears in the system. According to Martin Banke, CeramicSpeed’s cycling division head, these have been areas of key R&D focus over the past year.
“We’ve surpassed a speed of 45 km/h during rider load testing at the velodrome, and have had major breakthroughs in a shifting mechanism that we’re excited to unveil in due course,” Banke said in a company press release.
CeramicSpeed is clearly hinting at further developments to come, and with Eurobike just a week away, we suspect there’s more to this story. Stay tuned.