NuVinci continuously variable transmission for bicycles and other vehicles

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reikiman
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NuVinci continuously variable transmission for bicycles and other vehicles

In Electric Bikes, Go Green, Not Mean - Drawing The Line I noted someone discussing the need for a transmission on electric motorcycles. I think the same is true for electric bicycles. At Interbike I had a chance to try the NuVinci CVT and am very impressed.

It was on a bicycle but if you look around their website (http://www.fallbrooktech.com/) it's clear they are targeting other vehicles in addition to bicycles. On the bicycle there was a selector lever on the handlebar, and you chould change the ratio at any time you like. Unlike on a derailleur bicycle where the wheels have to be moving to change the ratio, with the NuVinci CVT the ratio can be changed whenever you want.

The ratio is determined by the positioning of some balls inside the CVT. It looks really cool.

I have a flyer from them in my hand saying the NuVinci is available in a ready-to-install aftermarket kit or pre-laced in a rear wheel. Unfortunately their website doesn't have a product description, but there are some press releases that discuss this

http://www.fallbrooktech.com/05_PressReleases_ibdprog.asp

http://www.fallbrooktech.com/05_PressReleases_biobike.asp

http://www.fallbrooktech.com/05_PressReleases_orgchange.asp

The press kit has a lot of information and a history of the company. An interesting thing is that they have a sister company who's using the NuVinci CVT in a small scale wind turbine.

http://www.fallbrooktech.com/presskit.pdf

Mik
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Re: NuVinci continuously variable transmission for bicycles ...

I think something like the Nu-Vinci design will be the standard for human-electric hybrid vehicles.

These will still work superbly even if the battery is empty and one has to rely on pedaling power alone.
You could have an electric bicycle which pedals as well as a (heavier) normal bicycle when the motor is not running for some reason.

But for applications where 'exclusively human powered mode' is not an option, like cars, planes, trains etc., other options are more likely to be successful.

This information may be used entirely at your own risk.

There is always a way if there is no other way!

jdh2550_1
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Re: NuVinci continuously variable transmission for bicycles ...

Do you know how efficient the NuVinci is? I hope to get one over the winter to play with. I seem to remember they do a "development kit"

The trouble with "traditional" CVT's (as seen on scooters, snowmobiles etc.) is that they are INCREDIBLY inefficient. Of course in the gasoline world the answer is to throw more power at it. In the EV world that's not a viable solution.

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Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

reikiman
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Re: NuVinci continuously variable transmission for bicycles ...

Do you know how efficient the NuVinci is? I hope to get one over the winter to play with. I seem to remember they do a "development kit"

The trouble with "traditional" CVT's (as seen on scooters, snowmobiles etc.) is that they are INCREDIBLY inefficient. Of course in the gasoline world the answer is to throw more power at it. In the EV world that's not a viable solution.

No, I don't. And didn't think to ask them that question. They do have a development kit that includes a hub (not laced into a wheel) and software for doing design work. My guess is it'll be more efficient than CVT's using gears but what would I know for real - I'd trust my opinion if I were a mechanical engineer. As a software engineer I just see "no gears, sounds more efficient" ...

I'm impressed that they have a broad vision about where this product can/should go. They're not limiting themselves to bicycles. This tells me they think they have a really good thing with huge potential. And that didn't feel like hyperbole

- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
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designtech3000
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Re: NuVinci continuously variable transmission for bicycles ...

It's hard to beat gears (spur gears in particular) for efficiency, assuming an equal number of reduction stages. Only chains rival them. Nuvinci uses a traction fluid like that in the Nissan toroidal CVT. I don't know how efficient those are though. If I rode one I'd have a good feel. 3-speed hubs don't feel nearly as efficient as chain drive and I bet most geared hubs, even today, aren't. If I ever get a chance I'll have to ride a bike with a Nuvinci. BTW, geared bike hubs don't use spur gears.

aidanworthington
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Re: NuVinci continuously variable transmission for bicycles ...

Iv had a quick look at the above website and it looks a good idea but i think it will have mager limitations when it comes to how much power it will handle if thoes balls slip or were out.I carn't c it getting far

LIVE LONG AND PROSPER

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