nigelme

Has anyone had any experience with the Infinite-Improbability-Drive; no hold on, I mean the Continuously-Variable-Planetary (CVP) transmission.

Made by Fallbrook technologies it sounds irresistable - "..less complex, has considerably fewer parts, offers more stable control, is better packaged, less expensive to manufacture and assemble.."

Could this replace the more common hub gearing? (SRAM, Sturmey, Nexus)

https://www.fallbrooktech.com/NuVinci.asp

Take a look at the Demo video - It's CGI so therefore not real!
Is this thing real at all? I can't find it for sale anywhere in the UK.

trentschler

Harris Cyclery lists it on their web site: https://sheldonbrown.com/harris/nuvinci.html

According to the site, it weighs 4100 grams/9.03 pounds.

destro713

I would quite like for something like this to replace bike gearing in general, honestly. Most old, time-tested bike technology seems to have aged gracefully, but the whole system of derailleurs, with exposed sprockets and cogs and a transmission controlled by using a piece of metal to yank a moving chain to the side, seems so very arcane, inefficient and dangerous.

Incidentally, I got my first taste of modern hub gearing the other day -- a Sturmey-Archer 3-speed -- and I loved it.

Hopefully this technology or some other new hub gearing technology finds a few big proponents, so popularity can be boosted, manufacturing costs can be lowered, and the design can be refined. Imagine if one of these things weighed 2 pounds and cost $200.

rhm

[QUOTE=destro713;5985270]...
Incidentally, I got my first taste of modern hub gearing the other day -- a Sturmey-Archer 3-speed -- and I loved it.
...QUOTE]
Modern! I love it, that hub's design hasn't changed since the reign of King George (not even sure whether V or VI). Just wait until you try an 8-speed.

destro713

Well... when I say modern, I meant modern as in more recently produced. I had tried hub gearing before on a friend's Raleigh 3-speed. If the S-A is from the reign of George V, that Raleigh hub is from the Precambrian or so.

Or maybe the design is exactly the same and the new one just shifted much nicer because it hasn't seen 40 years of action.

Fat Boy

I don't know about the arcane and dangerous parts, but it is actually quite efficient, which is one of the reasons why they are nearly universal.

nigelme

The Sturmey-Archer 3-Speed was first produced in 1903.

https://www.sturmey-archerheritage.com/history.php

I have one on my Brompton and it's excellent.

I agree the NuVinci does need to reduce it's weight to be a suitable replacement.

LittlePixel

It looks clever but it doesn't look to give a massive range of ratio.
I mean - the range is infinite but the difference of transmission speeds between the under/1:1/overdrive seem relatively small—which leads me to think maybe you'd need more than one of these mechanisms that work in series to give a wider range between the lowest and highest transfers.

Which is probably fine, but surely adds layers of complexity that can't help but add weight and offer more chance for malfunction.

The thing is - if this was a hundred years ago this drive would likely get the funding and be tested and in the public domain swiftly. I wish I understood why innovation like this forever seems to be at the prototype stage with no venture capital to get it properly ready for market.

Who *doesn't* want a non-jerky, non-incremental transmission system?

If I were prime minister my first job would be getting these babies fitted to all of britain's buses.
This being the one thing that might curb this nation's ever decreasing talent for stick-shifting on public transport.
So that grannies aren't constantly falling over. Or that your groceries aren't rolling about in the aisles.

LittlePixel

Ok so I played with Sheldon's calculator and find my gut feeling was not right - gain seems to be in the range -50% to +75% of original speed. My apologies - Ignore the first bit of the last post.

I do feel it could be miniaturised to use smaller ball-bearings (hollow?) though and with a more sensitive shifter do the same amount of ratio for less weight, albeit with more moving parts. Kind of like a Rolex.

I'm genuinely intrigued by this and would love to ride an equipped test bike. Or read any reviews if anyone's seen any?

BruceMetras

Not really a review, but This is interesting..

jur

Quite some talk about efficiency. But again frustratingly, no figures! It really does seem as if they are hiding the efficiency figures.

That said, I'd love to try one out.

LittlePixel

This review quotes at 97%

fmattheus

Here's an interesting review as well.
https://bikehugger.com/2007/07/mondo_nuvinci_review.htm

Bacciagalupe

The NuVinci was discussed 'round here about 6 months ago ( https://www.bikeforums.net/showthread...hlight=nuvinci )

FWIW my opinion hasn't changed, and as far as I can tell neither has the NuVinci. I still think CVP is a solution looking for a problem, the hub is too heavy, I can't imagine why you'd want or need to micromanage your shifting at all times.

Whatever uses it may have, until they shave about 4 lbs off it I doubt it will have much utility for folders in particular.

MnHPVA Guy

The new ones are nice, but no better than an old one that's in good running order. The older ones are slightly more efficient, running in oil instead of grease, though some people have "upgraded" the new ones to oil.

They've been making 3 speed hubs for 105 years. But the AW, introduced in 1938, was a clean sheet design having little in common with it's predecessors. It was produced virtually unchanged for about 65 years and there are only a few new parts on the Taiwanese made ones.

The new ones can not end up in a false neutral. But I've only had one where this was a problem, an alloy shelled 1953. It was on a Moulton Mk III with a convoluted, high friction cable run and had a weaker than normal clutch spring. A modern "slick" cable and new spring cured the problem.

I have overhauled many high mileage 50+ year old AWs that were on nearly worn out bikes. Usually they only need an R spring or two.

I first rode a Nuvinci equipped bike almost a year ago and there are several bikes sold with them now. I think the price is OK for what you get, but I'm waiting for the weight to come down. I hear they work great with electric assist bikes but I'm not that feeble yet.

nigelme

Ah someone has actually tried one.

I get the impression Fallbrook Tech are trying to drum up venture capital before any mass production.
The only use of a NuVinci I can find is at https://www.izipusa.com/trekking_li_nuvinci.html in an electric bike (Ed Begley Jr. uses them!)

Seems the bottom line relevant to this Forum is nobody is planning to use a NuVinci in a Folder.

awetmore

As with most bicycle transmissions the efficiency is not constant. The NuVinci is most efficient in the middle of the gear range and least efficient at the extremes.

I'm personally not that excited about the NuVinci. It is much heavier than a SRAM i9 while providing no additional gear range. As long as the steps are reasonable I care much more about gear range than having infinite gear steps.

OrangeClownBike

Frustrated by the lack of any reviews on this hub I went and bought one, then fitted it to my Dahon Hammerhead (not technically a folder, but close enough).

So first off the range is 0.5:1 (underdrive) to 1.75:1 (overdrive). With my 50/17 setup this gives me a 28 to 96 gear range this is slightly more than the standard 8speed that the Hammerhead came with. However as someone has already mentioned the efficiency does drop off a little at the extreme ends of the range so the useable range is about the same.

The efficiency is very good, I don't have exact numbers but in the middle portion of the range there is no noticeable drag at all, towards the extremes there is a little bit of drag, sort of like riding with a squeaky chain. I have not managed to get the hub to slip at all, even up some pretty big hills.

The shifter is very neat, but is a little awkward to fit with the standard brake levers.

Shifting is nice and simple, just twist and go! However, the resistance to shifting does increase as you increase the torque through the hub. If you put pressure on the pedals when you are not moving (say resting your foot on the pedal at the lights) you can't shift at all. This works against you if you have to shift down suddenly from a high gear whilst mashing on the pedals. It's better to ease off for a second whilst you shift down before applying the load.


The relationship between amount of twist at the shifter and the change in ratio doesn't appear to be linear. There is a much greater variation at the bottom and particularly the top end. The last few degrees of twist seems to push the gearing up quite a bit.

Overall the bike has gained about 3.5kg taking it to around 13.5kg from 10kg.

The extra mass only makes itself felt when I pick the bike up, on the move it's unnoticeable.

Now on to the riding impressions.

Really nice! Smooth and simple. Everyone who's ridden it has like it. Ok it's weight and slight drag won't make it popular with the racing set but for city commuting it's exactly what's needed. I've found myself adjusting my riding style to suit the hub. It seems to work best at higher cadences and works really well when you overtake. You drop down, spin up to speed and slowly wind the gears up as you sail past. I'm pretty certain this bike is the fastest accelerating bike I've ridden, especially when peddling from the seat only.

After about a month of riding I had a rash of broken spokes, this was traced back to my bikeshop lacing up a 2x pattern that resulted in a sharp bend at the nipple. They solved this by going to 1x, which they did for free (thanks Putney Cycles).

The next problem was when I noticed some of the fancy transmission fluid weeping out of the shift end of the axle.

A quick email to NuVinci confirmed that they have had some reports of leakage and a new shift rod could be supplied to solve the problem if I supplied my address.

Next day (I live in the UK) the shift rod arrived by UPS express! Now that's service!

Fitting it was simple (just unscrew the old one) and it appears to have mostly cured the problem. There is still a slight smear of oil coming through but nothing that could be qualified as a leak.

After about a month I noticed a slight leak of fluid from the main case joint. Again a quick call to Nuvinci sorted the problem. They replaced the hub with a brand new unit (more on that later) free of charge (including paying for shipping), no hassle, filling in of forms, sending my old hub back first or anything. Brilliant!

When i got the new unit the first thing I noticed was that the hub was a lot lighter, about 500g lighter, so it's now down to below 4kg. Still heavy, but it shows that the company are serious about the hubs and improving them. if they keep this up they could well get to the 2kg mark at which point it would be seriously attractive.

Overall, ATC/Fallbrook seem to be serious about getting this hub to work. My understanding is the big prize (for them) is in vehicles, particularly electric scooters and hybrids. Bike hubs are a convenient way to get lots of real world engineering data in order to get the hubs "proven" enough for car and scooter makers. As such they're prepared to invest a lot in these things. As I said, although I've had problems I knd of expected them as this is a MK1 product, but the customer service I have got is superb, so if you are curious about this sort of thing and aren't worried about a few kg's I'd recommend giving it a whirl!

jur

Thanks for this excellent piece of reporting.

rhm

I too got a Nuvinci hub recently, but not for my folder. I put it on my Xtracycle. Installation involves a certain pain-in-the-neck factor (in part because, for example, you have two shift cables going to the back wheel, while most bikes are designed for only one). But once everything was together and I took it out for a spin, I was pretty impressed. The trouble-free shifting makes for a wonderfully smooth ride. As OrangeClownBike mentioned, ease of shifting is not constant; it's a little easier to upshift than downshift, it's easier to shift under no load than when pedaling hard, and so on. But this hub is easier to shift than any other that I've tried.

The real test comes when my wife tries it out. I'll keep you posted.

geo8rge

One curiousity is it is hydrolic not mechanical. It works off the flow of a special fluid from the input to the output side (If I understand it correctly). I wonder if there will be more hydrolic parts for bikes in the future. Perhaps they could mount the input half in the bottom bracket.

jur

I don't think this is correct. The mechanism is substantially mechanical (how's that for clumsiness ), it is just the friction between input, balls and output plates that is made almost infinite by a special fluid that becomes a solid under high pressure.

chainstrainer

I found this new beach cruiser for $599 (including shipping) that features a NuVinci hub. Light bike weight is not an attribute of cruisers so the NuVinci's heft is not as critical. Many cruisers don't feature more than a few gears, many are single speed, so the NuVinci should be an improvement I suppose:

https://www.abikestore.com/Merchant2/...Store_Code=cbs

It's new technology so it can improve over time. I'm sure weight will drop and performance will rise.

jur

(Every time I see ridiculous mudguards like on that cruiser above, I wonder what the designers think they will do. Apparently despite this sort of thing being known for centuries, some people still think that water gets flung off a spinning wheel radially. Those mudguards would have worked to some extent if that was the case. But because water gets flung off tangentially, the guards are completely worthless.)

(Oh not completely worthless: They could serve as an example of how NOT to do it. )

geo8rge

Another 'traction fluid' transmition, for cars: https://www.torotrak.com/IVT/works/fluid.htm