Has anyone heard of this transmission for bicycles? Continously Variable Planetary, does this sound like something that is revolutionary. Any "engineers" in the commuting forum?
The Nuvinci Website:
The NuVinci transmission uses a set of rotating and tilting balls positioned between the input and output components of a transmission that tilt to vary the speed of the transmission. Tilting the balls changes their contact diameters and varies the speed ratio. As a result, the NuVinci CVP offers seamless and continuous transition to any ratio within its range, thus maximizing overall powertrain efficiency, with no jarring or shocks from the shifting process, and improving acceleration, performance and overall vehicle efficiency over conventional transmissions.
Here an animated demo.
FAQ about bicycle use.
Sheldon Brown website:
The most widely known form of internal gearing is the three-speed utility bicycle. 4-and 5-speed hubs have also been available for many years, but went out of fashion during the early '70's bike boom. Shimano, Sram (formerly Sachs) and Sturmey-Archer have started marketing 7- and 8-speed hubs. Sram offers a 9-speed model, and Rohloff offers a 14 speed model. Fallbrook Technology's NuVinci hub is continuously variable, essentially offering an infinite number of "gears."