Monday, April 12, 2010

"Better than Butter": NuVinci's New CVT Hub

NuVinci recently launched a new version of their continuously variable transmission hub - the N360. Its interesting technology, and an interesting application. As a continuously variable transmission, it varies the effective gear ratios based on input from the rider. CVT's have been in other applications; Subaru launched one in the Justy in 1987; to my knowledge this is the first application in a bike. The upgrade to the N360 reflects smaller size, lighter weight, and a $50 decrease in MSRP.

I had ridden the previous N170 version at City Bikes earlier in the day. It was fairly intuitive to ride, but I didn't immediately understand the "inchworm". As I twisted the shifter, the flat orange line gently curved into a hill, and then flattened again as I downshifted. Also, under load, the effort required to shift fluctuated.

At the launch event, Mrs. PDXebiker and I both tried out the new N360 on the trainer, and both found it easy to use. Unfortunately, it was so easy to use, that after a few shifts, it didn't require much thought at all, and we didn't really notice using it. Asked for our feedback, we couldn't come up with much more than "smooth", which seemed to be a the most popular response. City Bikes labels their (N170 model tester) "Like Butter!" - I'm not sure what's smoother than butter, but the N360 is. The "inchworm", I learned is a quick way to gauge what ratio you're in - handy at stoplights. The shift effort fluctuation is gone, too.

There were several other demonstration models on hand, in a variety of style frames. An urban bike, a mountain bike, a folder, a custom cruiser (later spotted in Pedal Nation's Pimp'd Bike contest), and an ebike all had the hub installed. Of course, bikes like that don't stay on trainers. Soon, people were slowly circling the room, trying out the hub, and smiling once it "clicked".

During a brief talk during the event, Alan Nordin, the President of the Bike Division of Fallbrook Technologies, detailed the benefits of CVTs, the improvements the upgrade to the N360 represents, and said that they specifically chose Portland to launch the product because "Portland gets bikes". Further, he specifically cited the ebike market as a target for them - people on ebikes appreciate the ease in shifting, comfort, and generally don't mind a little extra weight in the hub.

MSRP is (updated)$399, available through any bike store (they're carried by several part wholesalers) Kalkhoff's stocking a ebike demo unit locally; I'm excited to try it out off the trainer.

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