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What Is a Continuously Variable Transmission, or CVT?

By Wes Schwengels, February 20, 2018

When shopping for a car, you might think you only have two transmission options: manual or automatic. While that’s technically true, the world of automatic transmissions has changed a lot in the last couple decades, and now almost every automaker offers a continuously variable transmission (CVT). 

The first thing you’ll notice while driving a car with a CVT is smooth acceleration that’s not interrupted by shifting. Some refer to a CVT as a single-speed or stepless transmission because of its seamless ability to change gear ratios without delay. CVTs have an infinite number of gear ratios, allowing the engine to operate at its most efficient RPM at all times.

To better understand if a CVT-equipped car is right for you, let’s take a look at how they work and what makes them different from traditional automatic transmissions.

CVT vs. traditional automatic

Unlike a traditional automatic transmission, a CVT doesn’t contain multiple fixed gears. As automakers search for methods to increase performance and fuel economy, some have added as many as 10 separate gear ratios in their traditional automatics in an effort to optimize engine RPM.

The problem here is twofold: There is a loss of power each time the transmission shifts gears, and there is a limited number of potential gear ratios.

This is where a CVT has a huge advantage. Most CVTs use two variable-diameter, cone-shaped pulleys, connected by a steel belt. One pulley is attached to the engine input shaft, and the other to the output shaft that sends power to the wheels. One side of each pulley is fixed while the other is moved by a hydraulic cylinder. 

The cylinder is able to adjust the gap in between each pulley half, which changes the effective diameter of the pulley and allows the output shaft to spin at different speeds. As a result, a CVT never loses power while changing gear ratios and always runs at the ideal RPM. The CVT offers many advantages, but there are some inherent flaws, as well. Let’s take a look at the CVT’s positives and negatives.

» MORE: Manual vs. automatic transmission — which is right for you?

Advantages of a CVT

Fuel economy: Because the engine is always running at the ideal RPM, fuel economy is increased by around 6%, according to the Environmental Protection Agency. This saves you money at the pump. The transmission is able to do this by constantly monitoring driving conditions and adjusting the gear ratio to make sure your engine is only working as hard as it needs to. 

Smooth power delivery: With a CVT, there’s no delay every time the transmission needs to shift up or down. Your engine is kept at steady RPM and isn’t constantly bouncing up and down as you hit the gas or brakes. A perfect example is driving up a steep incline. While a traditional automatic will struggle to find the optimal gear and often shift multiple times in the process, a CVT will hold steady and continue to climb uninterrupted.

Lower initial cost: CVTs contain fewer moving parts than traditional automatics, and they are less expensive to produce. Aside from their distinct mechanical advantages, CVTs are automakers’ first choice in hybrid and electric cars, as they help bring down the cost of an otherwise more expensive car.

Simple, lightweight and compact: A CVT is a very basic transmission. Because it doesn’t contain multiple gears and other parts, it can be housed in a smaller case. This makes for a lightweight and compact transmission that can be used in many different platforms.

Disadvantages of a CVT

Driving experience: Although this is completely subjective, many first-time CVT drivers can feel a sense of disconnect with the car. CVT-equipped cars can feel spongy and soft, especially when accelerating quickly. With a traditional transmission, there is typically a harsh shift when rapidly accelerating. With a CVT, the engagement is smooth and less dramatic. Some can perceive this as a slower or weaker acceleration — even though it’s often actually more efficient and quicker. 

Engine sound can also throw people off, as a CVT produces a more constant hum compared with a car that’s constantly shifting gears. This can sound like a car that’s stuck in a low gear or even feel like a slipping transmission. To compensate, some automakers program fake shift sounds and fake RPM needle movement to make drivers feel more at home.

Cost of repair: Ironically, the lower initial cost of production of the CVT doesn’t translate into a lower repair cost. Often, a faulty CVT will require a complete replacement due to damage caused by the failed parts. Individual parts can be expensive and hard to find, and not every shop can repair a CVT. Additionally, CVTs don’t last as long, on average, as newer traditional automatics. That’s worth considering if you plan on keeping your car past its powertrain warranty period — typically four to six years, depending on the carmaker.

» MORE: Get an accurate estimate for your car repair

Bottom line

CVT technology has come a long way and, most of the time, its advantages outweigh its downsides. Take your time on the test drive and consider an extended warranty if you plan on keeping a car with a CVT for the long haul.

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