NuVinci gear hub

[stevebills]

I been looking at these hubs and are they the best thing since sliced bread

 

[tillson]

I been looking at these hubs and are they the best thing since sliced bread

No. They are inefficient.

 

[NRG]

Not to mention a bit too heavy and not supported with a motor....(well over 250w that is....strange as peak power with be way above this)

NuVinci® Forum • View topic - cyclone plus nuvinci

I really like the concept its just the weight and inefficiency...

 

[vhfman]

The NuVinci Hub is a continuously variable planetary (CVP) transmission, rather than internally geared hub.
There are no published data for the NuVinci hub efficiency, so the mention of inefficient is anecdotal. I am not sure if tillson has used the hub, but the answer posted may not be completely helpful. Derailleur gears are said to be 95-98% efficient when in good working order. Efficiency of the drive train on any bike is quite hard to measure in real world use, when chain and sprockets/cogs could be affected by wear, dirt, chainline and lack of maintenance. Internal geared hubs are quoted as being 8-10% less efficient than good derailleur setup.
The NuVinci hub is large and comparatively heavy, the latest N360 weigh 2.5Kg compared to say Alfine 8 speed weigh 1.7Kg.

Some of the advantages of the NuVinci for use with the Cyclone motor are that the chainline is constant to the driven crank ring. Unlike the line when using the conventional Derailleur gears. This means less chance of the chain skipping off, jamming and braking. As there are no discreet gears you can match the drive cadence to road speed continuously.
The weight of the hub is not an issue when you are using motor power to assist. If you think about it, you have the weight of the motor and batteries already added to your bike so you’re not looking at a light weight machine now anyhow.
As NRG mentions, the NuVinci hub is not warranted by Fallbrook for motor power over 250W, but I am not sure that would be a problem. I have seen systems with 10 times that power being used.
There is a perceptible drag from the hub but I am not able to measure how much. Again not a problem with motor assist, and I have not found a great problem pedalling without the motor powered. Here is a link to an independent review (not mine) MTB with N360 not motor assist.
One big down side with the N360 is the cost in the UK around £330. I got mine direct from the USA online store £250 inc shipping and tax, but that was last year September 2010. I think the Alfine 8 speed is about £200.
Then you have to add the cost of the wheel rim and spokes, plus if you are not able to build the wheel yourself, the extra cost of that as well.
The N360 hub is very smooth and you can up or down shift under load or static conditions.

I am just finishing a rebuild of my bike with Cyclone motor and NuVinci N360 hub.
Bike over view

 

[eddieo]

What a beast! Great job

 

[stevebills]

What size is the motor it looks big? lovely bike mate.

 

[NRG]

The NuVinci Hub is a continuously variable planetary (CVP) transmission, rather than internally geared hub.
There are no published data for the NuVinci hub efficiency, so the mention of inefficient is anecdotal.

Its mentioned in Fallbrook Techs own 'Nuvinci Experience' PDF, however, they go on to say that in real life riding because the CVT is always in the right 'gear' a rider becomes more efficient as he can keep the cadence correct for the riding conditions. In a straight measurement against a Derailleur the Derailleur wins out but they are at pains to point out that this is not the full story.

 

[Artstu]

​

That gives me an idea for a friends bike for her tricky chain tension.

Have you got more details on the chain tensioner please, is it home-made or an off the shelf part?

thanks​

 

[vhfman]

What size is the motor it looks big? lovely bike mate.

The motor size is the same for 650-1200W Cyclone. I have a 36v 20A controller.


And Artstu the chain tensioner is a Powerplay CHT100 Single Speed Chain Tensioner I got it from SJS it's spring loaded.

I must get rid of the Shimano decal on the chain stay as there are no Shimano part on the bike now.

 

[Artstu]

Thanks, that's perfect. I wonder is it possible to mount it so it pushes up rather than down, I'm guessing not though.

 

[flecc]

I wonder is it possible to mount it so it pushes up rather than down, I'm guessing not though.

Up is less efficient, chain taking a tighter turn. The difference is very small though, but every little counts.
.

 

[mechaniker]

Hi flecc,

sure every little count´s,
but i read in a big Mountainbike test, nuvinci against other hub-gears, the testrider havent seen any difference between this two system and the argument of this was that you can relly use the Pedal-ratio what you want and not must decide for a Pedal-ratio what is near by what you want as you must do on hub-gears, because nuvinci have´nt gear-step´s.
And the range of the Nuvinci is 360% this is more as a shimano and the only gear-hub what is sure better as the nuvinci is the rohloff but there is also the double price and so i ecxpect a differnce.
And the torque what i can bring into a nuvinci is higher as in other hub-gears.

regards
frank

 

[NRG]

I already mentioned this in post #7.

I suppose the proof is in the riding but I (and many others it seems) would still like to see some real measurements of this but Fullbrook seem not to want to publish anything, understandable though..... There are many posts over on the Nuvinci forum about efficency and some indication from Fullbrook themselves that derailleur efficiency starts at just over 90% and hub gears (theirs included) stop at just over 90%.....

 

[Streethawk]

I'd love a NuVinci, or a Rohloff (my wallet may not like that one), or even an Alfine 11 if it ever arrives. Hub gears are great, but, i wouldnt want an eBike to be front wheel powered, i think that's a handling compromise i wouldnt be prepared to accept.

 

[AndyOfTheSouth]

You probably know this already, but just in case, Warlands of Oxford are selling the hub (possibly the earlier version?) for £175. They have the 360 on a demo bike.

Warlands, Botley Road, Cycles, Bikes, Bicycles, Oxford, Oxfordshire,NuVinci Cycle Hub Gears

 

[Artstu]

Up is less efficient, chain taking a tighter turn. The difference is very small though, but every little counts.
.

Would I be right in saying that even a cheap derailleur is an option too, a bit of a waste perhaps, but it is cheaper than the tensioner gadget, or would the slightly wider single-speed chain not fit through one?

Shimano RD-2300 Rear Derailleur

 

[Streethawk]

Unless you can stop the derailleur moving on two axis then it wont be very good as a tensioner, because it will pull outwards as well as upwards. It may be possible to set the end point so it goes no further then you need, but then again it may not, as that adjustment is quite limited. It would look odd too...

 

[Artstu]

These tensioners are a bit cheaper On-One Doofer £8.00

and I also came across an Alfine tensioner on ebay

 

[flecc]

I suppose the proof is in the riding but I (and many others it seems) would still like to see some real measurements of this but Fullbrook seem not to want to publish anything, understandable though...

Peter Eland of Velovision who is hugely experienced with hub gears of all types is subjectively sure that the Nuvinci, including the latest one, is less efficient and he remains unconvinced about this factor, despite liking the Nuvinci in general terms. That assessment makes it way less efficient than a derailleur system.

some indication from Fullbrook themselves that derailleur efficiency starts at just over 90% and hub gears (theirs included) stop at just over 90%.....

These are supported by all the best sources, except for the "theirs included" when comments of such as Peter above indicate 90% is a bit high, since that would not give noticeable subjective inefficiency.
.