twinklefart ([info]twinklefart) wrote in [info]bikepirates,
@ 2007-05-05 17:47:00
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NuVinci hubs
Anyone know what this is? Holy moly...

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We had one at the shop I was briefly working at and it's incredible. The manufacturer calls it "continuously variable planetary technology", which uses spheres instead of gears to vary power. So there's no shifting...the resistance inside the hub is completely variable. You move the shifter and there's no clicking or hesitation whatsoever. You can "shift" while standing on the pedals and the chain doesn't jump or skip or any of that. It's hard to explain and really weird at first, but pretty cool, I think. Unfortunately it weighs 12 pounds or something.

Here's a link to their site.

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[info]warkie
2007-05-06 01:26 am UTC (link)
Pshaw... weight is nothing for someone who bikes for a workout. Sounds fun.

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[info]twinklefart
2007-05-06 03:58 am UTC (link)
Yeah, true. Plus, there's no derrailleur or cassette, so I guess that makes up for the weight a little...

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[info]warkie
2007-05-06 05:29 am UTC (link)
I've had major problems with every derailleur I've ever used. I would seriously consider something like this as long as I wasn't racing (which I never really have done).

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[info]cyclelicious
2007-05-07 06:52 pm UTC (link)
I saw the Nuvinci on a titanium frame last March at the NAHBS:

NAHBS: Titus with weird hub
"Titus with weird hub." Photo by me.


The designer from Titus told me how much weight it adds (which I've forgotten), but he also told me that he absolutely loves it.

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[info]dogoncouch
2007-05-06 02:42 am UTC (link)
That sounds pretty fuckin interesting. Now I'm just curious. Any idea how efficient they are, or how much they go for?

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[info]twinklefart
2007-05-06 04:21 am UTC (link)
Efficient? I don't know how you determine that. When you pick up the wheel and spin it backward, there doesn't seem to be any resistance. The wheel spins freely and comes to a smooth rest like normal. But the weird thing is, there's no sound. No gears to "ratchet".

If I remember correctly, they go for $5-hundred something WITH the built wheel. So it's not that expensive.

Actually a pretty good deal, I think. A guy at the shop took one apart, and from what I could tell it looked INDESTRUCTIBLE. Minimal maintenance, no derrailleur, etc...

Nothin' but big balls rollin' around and around.
Hey, that should be their slogan!!

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[info]dogoncouch
2007-05-06 06:08 am UTC (link)
500 bucks for a built wheel is about what I was thinking they'd cost.

Makes me wish I had some extra money lying around and a need for one of these.

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[info]skazat
2007-05-06 03:10 am UTC (link)
Ack. It's hard to get your head around how the ball bearings inside transfer power to actual spin the wheel around.

Wonder what happens if you pedal backwards, seems like it would work the exact same way. If so, variable speed no fixed gear... fixed gear - erm direct drive... without the directnesses.... gah.

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[info]y0ssarian
2007-05-06 03:26 am UTC (link)
I would assume that there is a freewheel in the rear cog. I have a feeling that the stresses placed on the fluid would cause it to heat up if it were used with a fixed cog. I suppose there's really only one way to find out.

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[info]twinklefart
2007-05-06 04:22 am UTC (link)
Yeah, the backspin is silent. Not a sound.

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[info]tuanscott
2007-05-06 02:25 pm UTC (link)
A lot of hubs are featuring that these days; it's not too hard to do with a ratchetless pawl (that doesn't prevent my friend's new Campy Centaur hubs from being as loud as a 1982 freewhel, though).

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[info]randomdreams
2007-05-06 07:16 pm UTC (link)
Campy hubs *always* sound like you're putting straws into a fan. But so do a lot of the Hugi hubs (and those are excellent hubs.) I've had poor luck with quieter hubs: they break in various nasty ways somewhere deep down in the guts.

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[info]tuanscott
2007-05-07 02:20 am UTC (link)
My new LX freehub is louder than the hubs I've had in the past, which surprised me.

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[info]gytterberg
2007-05-07 03:22 am UTC (link)
Planetary gears are basically magic, so this is like... extra dimensional magic.

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[info]y0ssarian
2007-05-06 03:14 am UTC (link)
Here is a link with a video. I'm not sure if its the same company, but it sounds like a similar idea. As for efficiency, I would assume that it is less efficient than a typical internally geared hub, which is less efficient than a derailleur. The upside is that it can be shifted under power or while the pedals are stopped, and, with few moving parts, it seems like it would be more reliable than an internally geared hub, assuming the fluid didn't leak.

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[info]livewirerc
2007-05-06 04:23 am UTC (link)
A guy on our critical mass ride a few months ago had one of these. I didn't get a chance to ride it but he loved the hell out of it and said the ease of use more than made up for the weight. It sounded interesting, but I'd want to try one before dropping the bucks for one myself.

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[info]twinklefart
2007-05-06 04:26 am UTC (link)
Unfortunately, the bike I tested it on was attached to one of those Bob trailers, so I couldn't really hammer down or nothing.

But I'd be happy to own one. I'd use it.


And NO, I don't work for them.

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[info]twinklefart
2007-05-06 04:24 am UTC (link)
Same company. NuVinci is the name of the hub, Fallbrook Tech makes 'em.

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[info]snarly
2007-05-06 03:51 pm UTC (link)
I'm not so willing to hand the crown to derailed systems on efficiency!

yes, they beat planetary gears on weight all the time.

75% of the gears on a derailed drivetrain are ruinous to the chainline, and that slows you down if your chain is the least bit dirty. admittedly, this can be avoided by careful restrictions on gear selection.

but I also consider "efficiency" in terms of "what if I don't touch this for 20 years". I don't know of any derailleur which has the duty cycle of the Sturmey-Archer AW, and due to the nature of the instrument, I don't know if I ever will. the planetary system crushes derailed setups in this arena!! it is a much more efficient choice when highest performance is not an issue, and maintenance time is precious. just ask China! (but please don't ask them about protein or glycerin)



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[info]y0ssarian
2007-05-06 05:08 pm UTC (link)
I was considering efficiency as simple power out over power in. You know, the real definition. The losses inside a planetary gear are much worse than the losses due to either the added friction of trying to move the chain out of plane or the looses due to the tight angles of a chain moving through the jockey wheels. I agree that planetary gears are great for longevity and when you're too lazy to take 3 minutes to grease your chain. But derailleurs will still win in efficiency.

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[info]tuanscott
2007-05-07 02:21 am UTC (link)
I think what you defined as "efficiency" would be better labeled as "durability".

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[info]bikeasaurusrex
2007-05-06 03:21 pm UTC (link)
Are those the same kind of hubs on the Trek Lime and the Raleigh Coaster?

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[info]fotoman311
2007-05-06 04:04 pm UTC (link)
no. Good question though. Those use Shimano's new coasting system. I'm not 100% sure, but from what I've read, that system uses an electric motor to shift an internally geared hub based on how much pressure you are applying to the pedals and how fast the bike is going, or something like that.

The Trek Lime retails at $700, so I wouldn't picture $500 of that going towards the rear wheel alone anyhow.

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More like the Trek Lemon
[info]tuanscott
2007-05-07 02:23 am UTC (link)
I'm definitely not getting the Trek Lime. It's great that they want to bring newbies into cycling, but for $700 you could get a much, much nicer bike that would be faster and look cooler.

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Re: More like the Trek Lemon
[info]fotoman311
2007-05-07 11:47 am UTC (link)
I agree.

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Re: More like the Trek Lemon
[info]fotoman311
2007-05-07 11:48 am UTC (link)
Of course $700 is the MSRP, but how much are they actually selling for in shops would be the other question. Still not cheap enough to justify I'm sure, but probably a little better.

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