When you buy a car with a CVT transmission what exactly are you getting? We break it down in this complete guide.
The Continuously Variable Transmission or the CVT has quickly become the transmission of preference for many automakers. Its history dates back hundreds of years but it’s only in the last few decades that we’ve seen it become so popular. Typically, CVTs offer enhanced fuel economy over traditional transmissions and they’re usually smoother in operation as well. Here’s a deep dive into everything you need to know about continuously variable transmissions.
A continuously variable transmission is unique in that it doesn’t have fixed unchanging gears inside of it. Most traditional transmissions do. When you hear of a five-speed or six-speed transmission those numbers refer to the number of physical gear cogs that are used for forward motion inside of the transmission itself.
A CVT replaces physical gears with a system that can slide between gear ratios instead. The result of this sliding is a smoother driving experience without the noticeable change of gears that you’ll experience in a car with a traditional manual or automatic transmission. For a deeper dive into types of automatic transmissions, including CVTs see this article.
As we’ve determined, a CVT doesn’t have traditional gears. Instead, most CVTs use a cone with a belt to reach the desired gear ratio. As the car’s ECU calls for a specific gear ratio the belt slides up and down the cone to provide the requested ratio. The result is that the engine’s power is transmitted to the wheels at the appropriate speed.
Some CVTs, like Nissan’s toroidal CVT, work with a combination of discs and roller bearings as opposed to cones and belts. Typically, they offer the ability to handle more torque than a conventional cone and belt CVT could.
Some CVTs have paddle shifters or gear selectors that emulate the feeling of traditional transmissions. When a driver selects one of these “gears” the CVT moves to preset points on the cone or disc. The result is a quick change in gear ratio and thus a simulation of what a traditional transmission feels like.
Continuously variable transmissions have a number of benefits. Since CVTs don’t need a complete set of gear cogs they’re oftentimes much lighter than a traditional transmission. Weight savings can improve a car’s performance as well as its fuel efficiency.
In addition, a CVT is typically more fuel efficient simply because it’s capable of optimizing the gear ratio based on conditions. Since it’s not limited by physical gears it can constantly aid the engine in getting the best fuel economy possible. It’s primarily this singular benefit that has made the CVT such a mainstay across so many vehicles in today’s market.
Fuel economy dictates a great deal for car companies so some have almost entirely abandoned traditional automatic transmissions. For example, Subaru does not use conventional automatic transmissions anymore outside of the BRZ. Instead, every other automatic they sell comes with a CVT. Even the WRX sports sedan gets a CVT on its top trim.
Finally, CVTs are typically much smoother in operation when compared to a traditional transmission. As a result, ride quality is enhanced and interior noise levels are typically lower too. Nevertheless, CVTs aren’t a perfect cure-all and there are some significant drawbacks to owning one.
Due to their design, CVTs often struggle with high horsepower and high torque applications. In fact, the roller bearing and disc version of the CVT was specifically created to handle more torque than a conventional CVT can. That makes most cars with CVTs bad candidates for tuning and modification.
CVTs are also known for slow reaction to driver input. Some traditional automatic gearboxes require a moment or two from the time that a driver presses down on the accelerator before the gears are swapped. CVTs can take even longer to change the gear ratio. For drivers who highly prioritize a feeling of connection and engagement on the road, a CVT likely won’t deliver as well as a traditional transmission will.
In addition, they can cause the engine to drone as they accelerate because they keep the engine at nearly the same RPM during that task.
Finally, CVTs often fail before conventional transmissions and they’re harder to work on as well. While some shade tree mechanics feel comfortable rebuilding conventional transmissions, CVTs often require a trained professional for basic maintenance, much less full-scale rebuilds.