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Your transmission’s job is to send a message from your car’s engine to its wheels, transferring power based on the gear ratio. 

But one type of transmission is becoming more popular: the continuously variable transmission, or CVT for short. Rather than use gears to determine how much power and torque the engine uses, a CVT continuously alters the power sent to the wheels by moving through an infinite number of gear ratios. This process keeps the engine in its most fuel-efficient operating range, adjusting wheel speed to correlate with throttle input through the CVT’s constantly changing gear ratios.

“Think of it as playing tug-of-war by pulling a belt to get more speed,” said James Jenkins, brand manager at Honda, which uses (offers) a CVT in all of its models besides the large Pilot SUV, Ridgeline pickup, and Odyssey minivan.

[Read Why Are Manual Transmissions Disappearing?]

Why should you care? Because there’s a good chance that your car has one. One out of every four new cars sold in the U.S. comes with a CVT, according to an analysis by Kelley Blue Book. Automakers have decided to include them in more new models after realizing that they’re lighter and more fuel-efficient. CVTs are in some of the best-selling cars on the market, including the Honda Civic to the Toyota Camry.

CVTs boast several advantages over traditional automatic transmissions. Their components are lighter, which cuts weight from the car and reduces wear and tear. Most importantly, they improve performance because the car shifts more efficiently than a driver can. They’re also easier to drive, Jenkins says: “You don’t need to downshift or wait for the computer to tell the car which gear to go to, which could take a second.”

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But CVTs also come with some drawbacks. They’re not compatible with all vehicles and are found on smaller cars because they can’t handle the torque made by large engines. The main criticism against CVTs is the droning engine noise they create during aggressive acceleration. This is because the CVT maintains a constant engine speed as the vehicle accelerates, rather than hear the engine speed rise and fall. A CVT can feel sluggish, depriving drivers of that joyful zippy feeling as a traditional automatic or manual transmission cycles through gears.

Honda and other carmakers have begun to counter this complaint by engineering “shift points” within the CVT in order to make it feel more like a traditional multi-speed transmission.

“They still have a ‘rubber band’ feel compared to traditional automatics, but they aren’t as bad as they used to be,” said Karl Brauer, senior analyst at Kelley Blue Book. “I think Honda has the best ones right now in terms of feeling almost like a traditional automatic.”