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Continuously Variable Planetary Drive Is For Bikes, Not Spaceships

By Evan Ackerman

The Ride

We’ve seen some bicycles recently with automatic transmissions, but a continuously variable transmission is something new. CVTs work without gears, or rather, they provide an infinite number of gears, increasing engine efficiency. In automobiles, CVTs are often pretty complicated, but the NuVinci transmission is simple and efficient, probably owing to the unrivaled genius of it’s original inventor, Leonardo da Vinci. It’s actually a CVP, or continuously variable planetary drive, owing to the rotating spheres that make up the heart of the transmission. Here’s how it works:

The NuVinci CVP is not automatic; you still have a shifter to adjust the bike’s power curve. But “there’s no hesitation, no noise, no waiting for the mechanism to “hunt” for the gear you’ve selected, nothing to synchronize, nothing to guess at, a simple twist of your wrist and you’re at a new ratio.”

You can currently buy bicycles featuring the NuVinci CVP drivetrain from Ellsworth; the base model is a shade under three thousand and the signature model (with some carbon fiber, a headlight, and a belt drive) will set you back another grand. A CVP kit should be available in the second half of 2007.

[ NuVinci ] VIA [ Core77 ]