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Inner gear ratios of the Nuvinci 360
#1
The following post is part of a topic copied from the discontinued NuVinci Forum. The majority is written by members of the old forum and not by me.

by FransM on Tue May 10, 2011 2:23 pm

I also have a problem with the internal gear ratio.
Although the paint markings were aligned I went through the reset procedure, with no avail.
My hub has a minimum of .57-.58 and a maximum of a bit more than 2. The range is close to 360 percent.
This is somewhat disappointing because for me the lowest gear is key and now it's around 15% higher than I had expected.
Can anything been done about this?
Thanks in anticipation.

Frans

Re: inner gear ratios of the Nuvinci 360
by NuVinciSupport on Tue May 10, 2011 5:20 pm

Hi FransM,

Have you had a chance to watch the installation videos on our website? They are very good for helping with the install process.

Link no longer available instead visit gearfreezone channel on YouTube https://www.youtube.com/user/gearfreezone

Hopefully this will help. If not, let us know and we will get you taken care of. As CadenceKing mentioned, you should be at 0.5 and going up to 1.8. for under drive and overdrive.
Keep On Smooth Cruising
NuVinci Support

Re: inner gear ratios of the Nuvinci 360
by FransM on Tue May 10, 2011 9:10 pm

Yes, I have watched the videos and read the manual umpteen times, but even while the yellow marks are aligned, and done the reset procedure nonetheless, when doing the wheel-rotation-versus-the-sprocket-rotation test, I get 0.58 to 2.10 for under- and overdrive.
So it seems to me there must be something wrong within the hub.
Any ideas? Thanks!

Frans

Re: inner gear ratios of the Nuvinci 360
by NuVinciSupport on Tue May 10, 2011 10:33 pm

Could you do me a favor and send me a private note with your email address. I would like to check with our head engineer and get his thoughts on this. I can then communicate directly back to you if we have any other questions.

For everyone else reading this thread, I will make sure to post a solution to the issue at hand when everything is resolved.

Thanks.
Keep On Smooth Cruising
NuVinci Support

Re: inner gear ratios of the Nuvinci 360
by FransM on Tue May 24, 2011 1:11 pm

Unfortunately, the discussion offline has not led to a solution.
The discussion wandered off to front-chainring/rear-cog ratio's but that has no relation with the problem of the internal hub ratio.
The internal hub ratio should be, according to the NuVinci specifications, 0.5 for underdrive and 1.8 for overdrive.
This can be measured by rotating the rear cog and checking the amount of wheel rotation which results.
I have done this a million times, applying resistance to the wheel to simulate riding load.
With my hub, the resulting ratios varies from 0.58 underdrive and 2.1 overdrive to 0.55 underdrive and 2.0 overdrive.
As you can see, the range is a bit over 360% so that is ok, therefore I assume the installation is correct, also the yellow paint marks are aligned, and resetting the hub gave no improvement.
I think this is a problem because the lowest gear which can be achieved with these ratio's is not low enough for mtb-ing or fully-loaded touring in hilly terrain.

I would very much like to hear from other hub owners what their ratios are and whether they have actually got the specified ratios.
I would also like to know what experiences others have with chainring/cog ratios below the recommended 1.8 so that the misperforming internal hub ratio can be compensated for.

Thank you all.
Frans

Re: inner gear ratios of the Nuvinci 360
by FransM on Mon Jul 25, 2011 12:58 pm

I have just installed my second Nuvinci 360 hub and again the internal gear ratios are 0.58 underdrive and 2.1 overdrive, just like my first hub and what braunbaer achieved with his hub.

My conclusion is that Nuvinci's claim of 0.5 underdrive and 1.8 overdrive doesn't hold.
This means that the gear-inches chart should also be corrected.

Re: inner gear ratios of the Nuvinci 360
by NuVinciSupport on Thu Jul 28, 2011 8:11 pm

HI FransM,

The nature of the N360 shift mechanism is that ratio under actual riding torque will be slightly lower than when under extremely low torque (like when doing “wheel counts” by hand).

Thus, speed ratio will measure slightly higher unless the rider is putting realistic pedal torque through the CVP. As a general guide, if the “no-load wheel count” full underdrive is approximately 0.56-0.58, actual full underdrive is approximately 0.5 when riding.

The nominal ratio limits of 0.5 and 1.8 apply at realistic pedal torque.
Keep On Smooth Cruising
NuVinci Support

Re: inner gear ratios of the Nuvinci 360
by FransM on Fri Jul 29, 2011 10:55 pm

Hi NuVinciSupport,

Thanks for your explanation.
I thought that applying some friction on the tire (as you instructed) would be enough to do the wheel counts measurement, but you're absolutely right in that it makes a difference when actually riding. I did a real-life-riding measurement today and achieved a 1.86 overdrive, being only 3% higher than the specified 1.8. I couldn't realisticly measure the underdrive ratio in the flat environment I'm in at the moment but now I'm more confident that that should be close to 0.5 as well.
Totally happy with my NuVinci hubs now, thank you.

Re: inner gear ratios of the Nuvinci 360
by NuVinciSupport on Sat Jul 30, 2011 4:50 pm

Glad it is all working out for you and that you are happy with the hub.
Keep On Smooth Cruising
NuVinci Support
- Oran
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#2
I missed this one on the old forum... really interresting!
The N360 is a complicated little fellow!
-
Si ça a déjà été fait, je peux le faire
Si ça n'a jamais été fait, donnez-moi juste le temps de trouver comment !


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#3
It is indeed complicated and that’s why it’s good to have a place to share this kind of information.
- Oran
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