Smaller, lighter NuVinci bicycle transmission revealed
The NuVinci N360 Continuously Variable Planetary (CVP) transmission for bicycles
Three years ago, Fallbrook Technologies introduced its NuVinci Continuously Variable Planetary (CVP) N170 transmission for bicycles. The device created something of a stir in the cycling community, as it replaces traditional derailleurs with a rear hub containing metal spheres, plus it also replaces distinct gears with a continuously variable system of transmitting mechanical power – kind of like comparing a three-setting desk lamp to one with a dimmer switch. Riders can change gears even when not pedaling, they don’t need to worry about improper chainring/cog combinations, and the fiddly bits aren’t out in the open where the dirt can get at them. The N170 is heavier than a conventional derailleur system, which is why you don’t see it much on bikes other than cruisers. That could change, however, with this Wednesday’s announcement of the NuVinci N360 transmission. Fallbrook claims it has all the good points of the N170, but is 30 percent lighter and 17 percent smaller.
Without going into too much detail, the CVP incorporates rotating, tilting metal balls positioned between the input and output components of the transmission. Tilting the balls via a handlebar-mounted twist shifter changes their contact diameters and varies the speed ratio. The N360 has six balls, as opposed to the N170’s eight, which is a big part of what makes it smaller and lighter.
Fallbrook states that the N360 has an increased ratio range of 360 degrees... it’s not immediately clear what that means, technically-speaking, but the result is more ratios to choose from. It’s also said to be smoother and easier to shift, and to require 50 percent less twist rotation to go from the lowest to the highest ratios. Because the hub interface is now housed inboard from the bike’s rear dropout, the transmission should stay cleaner and be better protected. The company also claims that due to the hub’s sealed design, it should not require any maintenance or adjustments.
While Fallbrook is particularly interested in getting their product on commuter and electric bikes, one can’t help but wonder how it would do on a road or mountain bike. Well, according to the N360’s spec sheet, it weighs 2.45kg (86.4 ounces). By contrast, the combined weight of Shimano SLX front and rear derailleurs, shifters, freehub and cassette comes out to about 1.3kg (46 ounces).
So weight-wise at least, there’s still a ways to go before it usurps the derailleur. If the N360 lives up to its hype, however, those extra thousand grams could be worth it.
About the Author
An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.
All articles by Ben Coxworth
Last time I checked, these guys were refusing the publish efficiency figures, which tells you something.
When you take the time to have a look at the manufacurer´s site you will find that the 360 degrees referred to in the article is in reality 360 percent or %. The site has a chart showing how far you go with one complete rotation of the pedals. The 360 percent refers to the difference of distance travelled for one pedal rotation between lowest and highest gear. Interesting to see is that a typical gear setup on a mountain bike will give you 581%.
The chart, in pdf is here:
\"The N360 has six balls, as opposed to the N170' 2019s eight, which is a big part of what makes it smaller and lighter.\"
Mine only has two balls making it faster and stronger.
Seriously tho.... I DO love the chain drives, but not out in the open.
As a friend once stated: \"Consider the cam chain in the average car, running at say an average crank shaft seed of 2000 rpm for 500,000K, - well the bike chains are cactus within 3 - 5000Km......
I am interested to see an (almost - and within reason) infinitely variable transmission - like this but giving a very broad range of ratio.
All you have to do is set the lower and upper limit - via screw stops... if at all.
Looking forward to a GREAT (almost) chainless bicycle drive.
this is best site. amazing information.
We talk about texting while driving, how about the danger of learning to shift a road bike? You never master the art completely.
Nuvinci\'s remarkable transmission is easy to use, unlike derailure gearing, which is decidedly not easy to use. It also starts in any gear and allows one to change one\'s mind, like you need when you decide to turn around on a hill. You might utilize a creature of Shimano\'s electronic derailure system for something as easy to use, but that is not available and may never be. (Stupidly, Shimano decided to keep the old manual controls!) The Rohloff geared hub can do most of what this device can do, but, along with complexity, it, too, is difficult to use by comparison. Of course, the lighter German hub has lower and higher gearing to keep its place to keep it thunking along. The world waits for Nuvinci to find the balls worthy of their remarkable invention.
Whats a couple of extra pounds to a fatso like me. The advantages of this system out weigh the weight issue. Now the price, that is an issue for the time being.
Thanks, Gizmag for bringing this great development to my attention. I am hoping to get one soon with a (new) full-suspension mt bike & will share my experience with it.
Keep up the great reportage of all these emerging technologies.
(PS Speaking strictly for myself---I am much more interested in technologies that help lots of people, than amazing toys for millionaires. )
Next up would be a bicycle transmission that self adjust either to a selected torque input (go for it NuVinci) or a selected cadance.
You need a lot less chain too I'm guessing, so it's comparative weight should be even less?
I've never considered shifting a derailleur-equipped bicycle to be difficult to use or master. Most shifting problems are the result a poorly matched rear gear cluster/front chain ring combinations, improper stop settings, dirty or worn springs that are no longer able to maintain proper chain tension.
Back when I was able to pedal a bicycle, Campagnolo was the king in bicycle hardware, Phil Woods had just introduced sealed bearing wheel hubs, and Shimano was a dirty, unmentionable never-to- be-spoken aloud name in polite company. My, how times and prices have changed over 40 years but a derailleur is still a derailleur. If the rider doesn't take 5 to 10 minutes weekly to wipe away the road grime and look for signs of improper wear and tear, it goes without saying that you'll complain about how derailleur-and-chain drives are the bane of the universe!
I am building my own hand-driven bicycle since fused knees, stiff legs and foot-powered pedals do not work well together. The NuVinci CVP might work better for me than a conventional chain drive. It will be an expensive option, but if it means that I can ride a bike once again, the money will be well spent.
Noel K Frothingham
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