Spats
07-13-2009, 11:42 PM
I rode a few bikes with the NuVinci gearhub.
For those of you who don't know, the NuVinci has...no gears. The gear ratio is continuously variable from low to high.
http://www.fallbrooktech.com/03_bicycle.asp
It's got a 350% range, which is more than a 1x9 (309%) or a road double (320%), but substantially less than a Rohloff or mountain triple. (And slightly more than the Alfine or iMotion 9.)
I rode three different bikes with the NuVinci hub. A Cannondale 29er hardtail, Ellsworth's "The Ride" chopper, and some city bike with an automatic transmission hooked to it!
First I rode the Cannondale, because it was the right size and I own a 29er anyway. The NuVinci shifter is a Grip Shift, but with no clicks. You spin it to wherever you want and leave it there, and since there's no shifting, it doesn't matter how much power you're putting to the wheel*, or whether you're moving forward at all. It just smooshes into a different cadence, and there you are. Kind of alarming the first few times, actually, but easy to get used to.
(*Actually it's a little harder to shift under load, but since it's kind of sticky anyway, it didn't make that much of a different, at least to me.)
Unfortunately the shifter has a lot of resistance and feels really "heavy". You can't just dump seven gears without effort like on a Grip Shift: you have to honk on that twistgrip pretty hard. On the other hand, you can do it in the middle of a high-effort technical uphill move, which is pretty damn cool because even a regular gearhub can't shift under heavy load. It completely avoids that "oh shit wrong gear" problem you get on short techy uphills amidst long downhills.
The gear indicator works well, too, though it has that "comfort bike" look to it: there's a little rubber band behind the window that pushes upwards into a big hill in low gear, and goes completely flat in high gear. You can tell out of the corner of your eye where you are, and whether you've got anything left on either end.
The major drawback: it's heavy. 2 kg, which is even more than a Rohloff or an Alfine. I don't see the point for any FS bike, since putting 5# of unsprung weight on the axle is stupid, and you'd need a chain tensioner anyway. But I can easily see this thing on a hardtail, especially one that gets ridden in mud a lot.
On the good side, it uses the derailleur hanger to keep itself from rotating in the dropouts, a much better solution than Shimano's separate non-turn washers, which can fall out if your axle nuts get loose and cause your hub to destroy itself; chainstay braces, which make it nearly impossible to fix rear flats or change rear tires; or Rohloff's solution of making you use weird adapter plates or buy a bike with Rohloff specific dropouts.
I didn't really enjoy the Ellsworth cruiser, but I find all cruiser bikes pointless, so I'm not the right person to review those.
The automatic transmission bike was actually a lot of fun. It was basically programmed for constant cadence; I would start pedaling from a stop, and though my feet weren't going any faster and my effort was basically constant, I would accelerate, which felt really, really creepy to someone like me who rides bikes a lot. I never managed to fool it, either, even with hard braking: it always reacted quickly enough that I was never left in too high a gear. It was basically constant-effort riding, like being on a stationary bike that would actually go to the store and back. It would be an awesome ride for amputees or someone with serious right wrist problems.
Anyway, my verdict is: the NuVinci does what it's supposed to, and if you're seriously looking at gearhubs and don't mind the weight, it's worth considering. You can get it in the mid $300s, or built rear wheels for $400-$450.
Amazon.com: nuvinci: Sports & Outdoors
For those of you who don't know, the NuVinci has...no gears. The gear ratio is continuously variable from low to high.
http://www.fallbrooktech.com/03_bicycle.asp
It's got a 350% range, which is more than a 1x9 (309%) or a road double (320%), but substantially less than a Rohloff or mountain triple. (And slightly more than the Alfine or iMotion 9.)
I rode three different bikes with the NuVinci hub. A Cannondale 29er hardtail, Ellsworth's "The Ride" chopper, and some city bike with an automatic transmission hooked to it!
First I rode the Cannondale, because it was the right size and I own a 29er anyway. The NuVinci shifter is a Grip Shift, but with no clicks. You spin it to wherever you want and leave it there, and since there's no shifting, it doesn't matter how much power you're putting to the wheel*, or whether you're moving forward at all. It just smooshes into a different cadence, and there you are. Kind of alarming the first few times, actually, but easy to get used to.
(*Actually it's a little harder to shift under load, but since it's kind of sticky anyway, it didn't make that much of a different, at least to me.)
Unfortunately the shifter has a lot of resistance and feels really "heavy". You can't just dump seven gears without effort like on a Grip Shift: you have to honk on that twistgrip pretty hard. On the other hand, you can do it in the middle of a high-effort technical uphill move, which is pretty damn cool because even a regular gearhub can't shift under heavy load. It completely avoids that "oh shit wrong gear" problem you get on short techy uphills amidst long downhills.
The gear indicator works well, too, though it has that "comfort bike" look to it: there's a little rubber band behind the window that pushes upwards into a big hill in low gear, and goes completely flat in high gear. You can tell out of the corner of your eye where you are, and whether you've got anything left on either end.
The major drawback: it's heavy. 2 kg, which is even more than a Rohloff or an Alfine. I don't see the point for any FS bike, since putting 5# of unsprung weight on the axle is stupid, and you'd need a chain tensioner anyway. But I can easily see this thing on a hardtail, especially one that gets ridden in mud a lot.
On the good side, it uses the derailleur hanger to keep itself from rotating in the dropouts, a much better solution than Shimano's separate non-turn washers, which can fall out if your axle nuts get loose and cause your hub to destroy itself; chainstay braces, which make it nearly impossible to fix rear flats or change rear tires; or Rohloff's solution of making you use weird adapter plates or buy a bike with Rohloff specific dropouts.
I didn't really enjoy the Ellsworth cruiser, but I find all cruiser bikes pointless, so I'm not the right person to review those.
The automatic transmission bike was actually a lot of fun. It was basically programmed for constant cadence; I would start pedaling from a stop, and though my feet weren't going any faster and my effort was basically constant, I would accelerate, which felt really, really creepy to someone like me who rides bikes a lot. I never managed to fool it, either, even with hard braking: it always reacted quickly enough that I was never left in too high a gear. It was basically constant-effort riding, like being on a stationary bike that would actually go to the store and back. It would be an awesome ride for amputees or someone with serious right wrist problems.
Anyway, my verdict is: the NuVinci does what it's supposed to, and if you're seriously looking at gearhubs and don't mind the weight, it's worth considering. You can get it in the mid $300s, or built rear wheels for $400-$450.
Amazon.com: nuvinci: Sports & Outdoors