cat0020

Some very interesting new things, Wired has a "Variable-Transmission Bicycle" article:

https://www.wired.com/gadgets/gadgetr...mmerguide_bike

Here is the Ellsworth site.

https://www.ellsworthride.com/

Plugging the name of the transmission into Google:

https://www.google.com/search?hl=en&q...=Google+Search

Gets this:

https://www.atcnuvinci.com/overview.php

The transmission looks pretty cool.

Other bicycles:

https://www.atcnuvinci.com/where_partners.php

Distributors:

https://www.atcnuvinci.com/where_distributors.php

Only place with a price so far is eBay item 110138363262:

https://cgi.ebay.com/NuVinci-CVP-Mode...QQcmdZViewItem

Google search for price:

https://www.google.com/search?hl=en&q...ce&btnG=Search

One article seems to indicate it is not officially released as an
independent product, but it does say second half of 2007:

https://ohgizmo.com/2007/03/27/contin...ot-spaceships/

More:

https://www.treehugger.com/files/2007...llsworth_r.php

Another link for electric scooter and bicycle drivetrains with a pdf
of some specs:

https://www.atcnuvinci.com/docs/LEV_Datasheet.pdf

Retro Grouch 

The big design problem with bicycle drive train parts is the wimpy motor. There simply isn't any power to spare. Derailleur chain drive systems are so efficient that they are hard to match.

The problem with most CVT systems is the high contact pressures that are required for the power transmission. In this case, a drive disc and a driven disc press at different points on ball bearings to provide the variable transmission. I'm thinking that pressures strong enough to keep the system from slipping are going to eat up a lot of power.

HillRider

The Nu-Vinci CV bicycle transmission has been in the news for a couple of years but remains an "any day now" product. We'll see how effective it really is when and if it goes commercial.

RG has a very good point. Current bicycle transmissions are so efficient that anything else has a very high bar to overcome. There is not much power to waste.

d_D

Thread in the commuter forum. Someone has one and says they are available on bikes in the Netherlands so I guess they have gone commercial.
https://bikeforums.net/showthread.php?t=281858

Judging from the ebay auction it's heavier and more expensive than other geared hubs. Bit of a gamble if your a manufacturer specing a bike as your bike will be heavier and more expensive than the competition.

makeinu

There are a couple people around the forums that claim to be running these hubs.

Krow

Like me. I have a NuVinci hub running on my Giant Lite electric. Since the electric is already a heavy beast, this just adds to the fun. Total weight with the NuVinci, the motor and the battery is around 60 lbs. Good thing I have a motor to help me!

Like other internal hubs, it lets you change the gearing ratio at any time, even standing still. Since it's Continuous, I have very fine resolution on adjusting the gearing ratio.

This electric bike's motor drives through the chain to the rear gear, so the motor gets to take advantage of the gearing I select. The bike's controller adds motor power based on my cadence, so having fine resolution on gearing lets me balance the motor and my contribution with a lot more precision than the regular 4-speed gearing the bike came with.

The hub itself has been working great. I've had it for about 2 months now and have about 400 miles on it. No problems to report so far and the hub has worked especially well with the electric assist.

fransb

It's me .

Yes they are commercial now.

Take a also a look at https://www.breukelman.net/nuvinci-e for more information about this hub.

cs1

Right now they are big, heavy and expensive. As technology improves, the weight will come down and strength will increase. I predict that production will shift offshore and price will drop also. IMO, this is the wave of the future.

Tim

HillRider

Like RG said above the usual bike motor has very limited power capacity and can't afford to lose too much of it due to mechanical inefficiency. Add a additional outside motor and all bets are off.

wroomwroomoops

A few coments:

• this hub is rather heavy: 4.1 to 4.2 Kg without freewheel and brake
• hub gears have proved to be very efficient, actually, and only about one percentage point less efficient than derailers - however, at low gear ratios their losses are higher. This is true for non-CVP
• is there an advantage of using this CVP hub gear compared to a Nexus-8 in terms of robustness? The Shimano Nexus and SRAM Spectro hubs are not known to be very sturdy, so people are discouraged from using them in XC or DH. I am looking for something sturdy for a tandem bike.

fransb

Yes. The concept is much simpler. Simpler designs are (mostly) more robust.

TO11MTM

How much are you going to beat on your tandem? I don't have many miles on it yet but the Nexus 8 is holding up well on me and the ladyfriend's tandem so far.

On the plus side, I saw one of these hubs for sale in a US Distro book and they seemed priced pretty competitively for what you get, they were more than a shmano Nexus but Far less than a Roholff.

wroomwroomoops

Could you give some references, other than just yourself?

But if you have only yourself, still, could you provide more details on your usage of this hub?

essex33

I just got an Ellsworth Ride with the Nuvinci hub about 2 weeks ago. Too soon to elaborate on specifics of quality but from my experience so far it's a blast to ride. My bike is a cruiser but it has lots of carbon and I use it for mostly street/trail riding pleasure. The shifting / riding is extremely quiet and smooth. The hub is approximately 9 lbs weightwise. I am enjoying this ride so far.