NuVinci Continuously-Variable Bicycle Hub
As cyclists, all of us are used to having a certain number of gear choices available to us – from one to 27. Most of us are also used to never being able to find the “right” gear, shifting through the gears hoping like a junkie that the next shift up or down will be the one that puts us in our sweet spot. So it has been for as long as we have had multiple gear options, and so should we ever expect it to be, right? Not so, now that NuVinci has come out with the continuously variable planetary (or CVP) hub.
The NuVinci CVP hub offers a continuously variable range of ratios via a set of rotating spheres within the hub – or, as Fletch said, “It’s all ball bearings nowadays, son.” How it works is a little beyond me to explain, but as you shift, the contact diameter of the sphere changes, permitting a smooth seamless progression of speed ratios. What does that mean to you? No longer are you limited by having a certain number of gears. Instead the rider shifts and pedaling just becomes easier, or the resistance is icreased for higher speed. There is no gear stop, no limit, just an easy slide through the “gears”, even though it is more akin to tightening down the resistance on an exercise bicycle than shifting. I rode one of these hubs at the NAHBS and was at first amused that there were no numbers on the shifter – just a little bicycle and a hill that gets steeper as you increase resistance. At first amused, then amazed – this hub is fascinating, and a real new direction in bicycle gearing. Imagine what kind of scoreboarding you can do with your friends; “Oh, Campy 10 speed? That’s nice. I have infinite speeds…”
If you are building a bicycle and considering an internally geared hub, I’d suggest looking very hard at the NuVinci CVP. The hub is currently available on many models of current bicycles from the top brands, and it is also available to build your custom bike around. I have to say that of all of the amazing things I saw at NAHBS, the NuVinci is really the most important – it is a revolution in power transfer technology for bicycles, and at what I consider a really reasonable price point for such interesting tech.