Automatic shifting for bikes

[mvrider]

Not sure if this is new or not, but the implementation sounds unique. I wonder how efficient the ball-based continuously variable transmission is?
http://www.bikerumor.com/2012/07/14/nuvinci-n360-harmony-electronically-thinks-shifts-for-you/#more-46068

NuVinci’s new N360 Harmony is an electronically controlled, auto shifting internally geared hub that gives you two modes of control.

Unlike Shimano’s Alfine Di2, the NuVinci system “shifts” for you to keep your cadence at a preset RPM. And, because their hubs are a type of planetary gear, there’s no actual stepped gears, so it feels seamless. It’s called Cadence Control and it’s rather unique.

Set your cadence and as you pedal harder or softer, it changes the gear ratio to keep your cadence the same. The cadence range is from about 60 and 85 rpm, but it depends on front and rear gear sizes, and OEM brands can specify tooth counts and program the desired cadence spread.

I rode it around and it feels as uncanny as the concept sounds. Pedal a bit harder and it shifts imperceptibly and all of a sudden you’re going faster without really pedaling any harder or faster. It’s strange, but it works.

http://brimages.bikeboardmedia.netdna-cdn.com/wp-content/uploads/2012/07/Nuvinci-N360-Harmony-electronic-autohshift-bicycle-gears03.jpg

[Louis]

Sounds like it would be fun to try.

But will it make me faster? If so, I'm all over it.

[Chance]

I rode it around and it feels as uncanny as the concept sounds. Pedal a bit harder and it shifts imperceptibly and all of a sudden you’re going faster without really pedaling any harder or faster. It’s strange, but it works.

Well, to go faster we need more power so a rider has to either pedal faster or harder, or a combination of both. The claim highlighted seems ludicrous.

The CVT part is not new. They’ve been around for years. The automation part to control gear ratio based on cadence may be new for this type of CVT, and may be OK although there is no reason to believe that humans like to pedal at constant cadence when power demand changes. That implied assumption seems questionable or maybe a little flawed to me.

For serious cyclists it’s more likely that Shimano’s electric shifting can be automated to resemble the newer automotive transmissions based on automated shifting of a manual-like transmission. Don’t see why derailleur system can’t be pre-programmed to shift based on power, cadence, or anything else the rider sets up in advance. For me manual shifting of any kind sounds best although trying one would be fun.

[KidWok]

The NuVinci stuff has come a long way since their first gen...I think it was a 14 lb hub. I don't know that I would always want to be at the same RPM, but maybe it would just take some time to adjust. I see those guys all the time at Portland and Seattle Expo's...will have to check this out next year.

Tai