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Discussion in 'Downhill & Freeride' started by davod, Oct 23, 2005.
I'm surprised that this wasn't beaten to death earlier, it was at interbike.
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Wow. That's an interesting take on it. Almost so simple it's silly.
that is VERY cool.
I'd like to get my hands on one...
could this be the affordable internally geared hub we've all been waiting for?
don't think that thing will be even remotely inexpenise if it is to work right. the thing is working under a ton of pressure (actually probibly more). i can see this thing slipping under high loads of sprinting.
cool idea though
one of the benefits they list on their site is ease of manufacture, so I guess we'll just have to wait and see.
they buit a wicked cool lookin prototype: (dl the movie)
interestingly enough, I saw this very CVT a few weeks ago in a paper on Variable speed wind turbines on NREL.gov. go figure
Check out the video at Fallbrook Technologies. That is some beautiful machine work!
Wow! That thing is a crazy simple concept, yet so effective. Id love to try one.
its mentioned on their site that one of the applications would be used for wind turbines. I'm kinda with the Sir on this though, i'm a bit skeptical on its ability to provide the "torque density" required (as they put it) for a more aggressive application. It's too bad they dont provide any data, if it works as stated it could be the holy grail.
Vicious rumor dept: didnt DW mention he was persuing a new tranny technology to be applied in a g-box format?
Yeah, I dont think they have the data to extrapolate up to wind turbine sized applications. I say that because in that NREL paper, they simply assume that it could take the torque loading and would only add 20,000 to the cost of the gearboxes already used. In some ways its not a stretch though, becuase they do state they can add more of the planetary balls to increase capacity, up to 12.
not only that but use multiple units inline like how planetary systems are arranged in car automatics
Wow, if it actually works, this is a cool step forward.
I'd love to get my hands on one for testing.
Any pictures of the shifter?
The shifter would most likely be a grip shifter of sorts.
Awesome idea! I didn't think it would work until I saw that there was a horizontal axle going through each ball. I can see grip shift working better than any other method, but I hate the way it feels.
I think it's funny that this is called the 'NuVinci', and another cvt hub posted earlier was called the nupace of something.......
being an indexless system i could see a bunch of different solutions, even electronic shifting (see how they shifted by rotating that handle? replace with a small DC servo).
I could see electronic shifting being pretty cool...two thumb buttons, one to move your ratio up, and one to move down.
Or, just an old-school non-indexed friction shifter.
I'd stay away from gripshift style if I was designing it myself, as they are indexed and have a pretty heavy activation pressure to move them, as you don't want to jostle your ratio while riding something bumpy. I'd want to keep a light, non-indexed action on the shifter, so it would be easy to find your ideal ratio.
Toroidal CVTs are nothing new, first patented in 1886, they are widely used in heavy industries. Typically the units are very heavy due to the massive forces involved, and have decent efficicency (80-92%). It will be interesting to see if this technology can successfully be used for bicycles. I am watching. It's a considerable engineering challenge to get the efficiency up to match a chain system. Should be fun to watch!
Zedro, yes, I am still working and filing for patents, but I am taking it one step at a time. No need to rush it. If what I am working on does in fact work, it will be very good I think. If not, no harm done, it has been fun so far!
ZEDRO! The mindless herds of Newbs on MTBR need you!