Nissan made two bold moves when redesigning the 2013 Sentra.

First, it did a particularly good job on the tried-and-true plan for freshening compact cars: make it bigger, smoother, quieter, nicer and prettier looking.

The new generation Sentra does all that, which makes it a dramatically better car than the rather forgettable 2012 model. It’s a big step above the Versa sedan, which currently slots at the bottom of Nissan’s sedan lineup, and is closer to what drivers used to expect from the mid-size Altima.

It’s a solid-feeling car, one that doesn’t seem like the bargain-basement economy car that the Sentra was 10 years ago. It’s a more grown-up car now, aimed at “professionals” who want something mature, comfortable and stylish.

A new look for the body, complete with Audi-style LED accents, and classy cabin materials are a big part of that.

But the second major change is a geeky mechanical advancement found deep within the Sentra’s transmission: a sub-planetary gear.

For some background, Nissan has been deeply committed to continuously variable transmissions (CVTs), and the new Sentra includes a big, noticeable advancement in CVT technology.

CVTs don’t typically have traditional gears with teeth. Instead, they have a system of pulleys that change the gear ratio depending on the vehicle’s speed, making the car feel like it’s powered by rubber bands.

Personally, while I understand the logic behind them, I’ve never been a fan of CVTs because they don’t feel as responsive as a modern, traditional automatic with real gears in it.

In this new Sentra, though, I had my best CVT experience to date. This transmission uses what Nissan calls a sub-planetary gear to shift between very high and very low ranges, which means the transmission can use smaller pulleys and respond faster to input from the driver.

It also means the new CVT design can deliver a higher gear ratio of 7.3-to-1, which is better than seven-speed automatics and currently the highest ratio of any automatic transmission in the world.

See, I told you it was geeky.

All that engineering effort results in better gas mileage and a more responsive feel when you stomp on the accelerator. It’s a good fit for the fun-to-drive Sentra, with its sporty suspension and tossable, lightweight impression in curves.

Despite the new Sentra being considerably bigger than the old one, it weighs 150 pounds less now. The lightweight construction, along with the fresh CVT design, contribute to a big jump in gas mileage.

Highway fuel economy is rated up to 40 mpg in the Sentra FE+ model, while ordinary Sentras with the CVT are rated at 39 mpg on the highway and 30 in city driving.

Combined fuel economy is 34 mpg, which Nissan claims leads the Sentra’s class.

Everything about the cabin has moved upscale — materials, technology and spaciousness — with one exception: the size of the digital screen on the center stack. Its 5.8-inch size is a bit small for a freshly redesigned car.

Pricing starts at $15,990 with a manual transmission or $16,990 with the CVT.

Derek Price is an automotive columnist for CNHI News Service. Contact him at carcolumn@gmail.com.