Originally Posted by
tubesocksFred
There definitely is a gearing problem with some of these NuVinci bikes. I always suspected it, but can't be sure, thinking it could be due to headwind or maybe the jeans I am wearing were too grabby. But the last one I rode, I was spinning like mad and thought I don't feel like I am going that fast, so I pulled up next to someone riding the new 3 speed ones, and I am definitely doing a higher RPM.
Then as I docked, I gave it a rough measure of how many wheel turns I will get for every turn of the crank, and it was around 2.4. Then I grabbed went to another NuVinci bike and measured something like 3.3. From now on, if I encounter a NuVinci whose highest gear feels low, I will press the wrench button. Or maybe I won't even take one of these bikes out, since the chance of getting stuck with a low geared bike seems pretty high.
This is confusing and contradictory, first the hubs are only able to spin at a max of 1.7 wheel rotations to one rear cog rotation. Secondly if you were spinning at a higher RPM you would have seen the wheel spin at around .5 rotations per rear cog rotation. If you look at the max under/overdrive on the nuvinci link this will show that the lowest and highest "gears".
To put this in perspective, the Sturmey-Archer's highest gear is 1.33 wheel rotations to rear cog rotations. The Shimano Nexus is 1.36. So the overdrive gear is a higher one. The low gears for SA=.75 and for Shimano=.73. So the NuVinci hub does have more of a low gear. Maybe you are turning the shifter in the wrong direction, but the gearing should be more than enough to enjoy the riding in the city.
Also if you look at the Sheldon Brown gear calculator, as I did below, you can see an immense difference. The overdrive on the Nuvinci is a little skewed because Sheldon Brown does not have the 330 hub just the 360 and 380, so I used the 360. Also the video might help, it is in a different language but it explains how the hub works from the shifter to the actual internal parts. I hope that helps because I love riding my Priority bike with a 330 on it and can't wait to get back to New York to get on the new Citibikes!
Commercial Groupset N330f - Products - nuvincicyling.com