My first thought upon unboxing the Breezer Uptown Infinity was, “Wow, that’s nerdy.”

Like all Breezers, it’s pretty much the textbook definition of a “commuter bike.” It has a relaxed aluminum frame, a set of wide, swept-back riser bars with comfort grips, a cushy leather saddle with hydraulic suspension built into the seat post, plus more bunting than is probably necessary — rear rack, fenders, chain guard and a set of lights powered by a Shimano Dynamo hub.

This is the Oldsmobile Cutlass Ciera of the bike lane. It has a vibe that very calmly announces, “Hello, fellow citizens, I am riding to work on my bicycle.” All that’s missing is a matching Thermos and a copy of USA Today.

But the Breezer has an ace up its sleeve. At the back end of the drivetrain sits a Fallbrook Technologies NuVinci N360 “seamless shifting” hub.

This thing is a marvel. It’s a continuously variable transmission hub. Instead of offering a fixed selection of gear ratios that you mechanically shift between — as in other multispeed hubs — the NuVinci just glides up and down through the range of the transmission as you twist the grip shifter. It uses a circuit of freely rotating spheres instead of a standard planetary-gear system. (Rather than try to explain its inner workings in detail here, I’ll direct you to our previous coverage of Fallbrook and some YouTubery).

You get all the same advantages of a traditional internally geared hub — sealed case, low maintenance, the ability to shift while stationary — but you can shift under force, and you aren’t limited by the selection of stops on the shifter.

Pedaling it around town is a kick. You twist your right hand towards you to go harder, and away from you to go easier, just like a motorcycle’s accelerator. It’s very easy to get used to. After only about 10 minutes on the Breezer, I was instinctively going back to the easiest setting at every stop light, then twisting the shifter as I sped up.

The entire concept of “shifting gears” is eliminated. Accelerating through the range of the transmission is much more pleasurable than the choppy, click-click-click routine we’re all used to. Getting the Breezer up to speed from a dead stop is smooth and quick, even when you’re pushing the cranks as hard as you can.

It’s really cool to be able to dial in exactly the level of efficiency you want, especially when going up hills. On a regular bike, you might be stuck in a situation where fourth gear is too hard and third gear doesn’t give you quite enough power. With the NuVinci, you can dial in gear three-and-a-half, or even gear three-and-nine-sixteenths. Hence the “Infinity” in the bike’s name.

It ain’t all roses. I would have preferred more gas at the top end of the hub’s output. Also, if there’s a setting you particularly like for the hill by your house, good luck finding it again. You just have to go by feel.

The hub’s range is 360 percent — better than a SRAM iMotion 9 (340 percent) and a Shimano Alfine 8 (308 percent) but not as wide as a Rohloff (526 percent ) or some other high-end hubs. At 5.6 pounds, it’s also heavier than most every other comparable internally-geared hub.

Add that hub weight to all the comfort features and the Breezer Uptown winds up just shy of 35 pounds. As such, piloting it through traffic takes extra concentration and muscle, and carrying it up and down stairs isn’t any fun and should be avoided at all costs.

But don’t worry — your office mates will forgive you for hogging all that space in the elevator after you wow them with your dissertation on the inner workings of your bike’s strange and unusual hub. Can’t you just see it now? Their breathless, wide-eyed amazement as you explain continuously-variable-transmission technology? You’ll be the office hero. Bask in the adulation!

WIRED Breezer’s famous comfort factor is on full display here — it’s like riding your sofa to the office. Smooth-shifting NuVinci N360 hub has a virtually infinite number of gearing choices. Traditional and step-through frame types available. Chain guard and fenders keep your pleated Docker khakis as clean as a whistle. Built-in Dynamo front hub system means you’re never caught in the dark.

TIRED It’s heavy — stairs and hills will have you huffing and puffing. Hub could benefit from a little more oomph at high speeds. Styling is best suited for soccer dads and Ned Flanders types.

Photo by Jon Snyder/Wired.com