I've been riding on the Nuvinci hub now for the entire season. I put an average of 80-90 miles a week on Byron and have come to love both the bike and the CVT.
The Nuvinci hub is an incredibly smooth and efficient transmission with a great range of ratios and in my experience is far superior to the Shimano Nexus hub.
The shift mechanism is a real pleasure. It feels a bit stiff when shifting while pressuring the pedals, but I have had no problems with the operation at this point. Since the transmission has no specific gears the experience when riding is truly intuitive. I look at the indicator at stop signs to pick a reasonable starting ratio, but forget it entirely while riding, and am able to make minute and continuous adjustments for the wind and terrain.
The only problem I encountered was something I caused myself. The installation of the shift mechanism was surprisingly simple and straight forward. I was smart and left enough cable to allow for slack to remove the wheel without disconnecting the cables, so that when I had to change a tire, it would be simple--right?
Well, not exactly, see it all leads back to the nifty ring lock I put on the rear wheel. I really love having those locks on the bike
but a couple of times I have found the bike in a different location on a bike rack. It means a possible theft was foiled and the would be thief left it in a convenient spot and I presumed ran. It happened one day that the thief must have been pissed because the tire was flat also. Fortunately I was close to home and just walked the bike back, flipped it over, and removed the wheel. It was easy, I left the cables installed, removed the tire and tube, put a new tube in, replaced the tire, inflated it and replaced the wheel. I never found a puncture in the tube I removed so I know some evil creature lurked out there and got me!But the real story begins here. When I rode the bike the next few days, I noticed a grease collecting on the spokes and the shifter was working harder. I cleaned up the grease residue, put the bike on the stand over night and inspected it in the morning. I found a dark trail of grease on the side of the hub, panicked and assumed the hub had broken and gone bad. I immediately e-mailed the customer service department and, although they were slow to respond, they offered to inspect and replace the hub with out any problem.
Now the good part.
I was wrong!
When I removed the wheel, I found that the shift interface,
that groovy little magical widget on the cable ends, had split open somehow. The grease had come from that.
I removed it and found it wasn't full of magic at all, but little nylon gears, six to be exact. The case for this little gizmo had apparently come unsnapped after I removed the wheel with the cables attached. Nuvinci had no problem with replacing it even though I admitted I may have done it myself. They sent me a new one right away and installation was not a problem. One thing to remember is the default setting for the hub is full overdrive (high gear). Make sure the highest gear is fully engaged before disconnecting the cables. If you don't there are simple instructions to restore it in the manuals.
So what have we learned? Nuvinci hubs are a lot of fun to use, ring locks work well
and frustrate the crap out of potential thieves,
always disconnect the cables before removing the wheels,
always leave the transmission in high gear before removing the cables,
and, (surprise!) I am not smarter than the guys who invented a revolutionary new transmission system.