Continuously variable transmission or “CVT” is a household term these days in the automotive world. People either have no idea what they are, they love them, or they hate them. There just isn’t any middle ground.
Why is this?
It’s because the CVT is both wonderful and terrible at the same time. It’s also a technology that’s only started becoming mainstream in the past several years.
We’ve touched on what a continuously variable transmission is before, but if you’ve forgotten, let’s briefly go over it again.
A continuously variable transmission is a belt-driven transmission that doesn’t have gears, and thus, doesn’t shift like a manual or regular automatic transmission. Rather, the vehicle’s computers allow the belt in the transmission to constantly operate within the optimum ratio needed for any given situation.
Think of it like shifting the gears in a bicycle. But, instead of having a chain, the bike is powered by a belt. And, instead of having visible gears with teeth, just imagine a cone on which the belt is able to slide.
The cone is the same diameter as all the gears – larger on one end and smaller on the other – but the chain doesn’t have to “jump” to the next gear. You can still adjust the speeds on the bike, but the belt just slides back and forth from the largest part of the cone to the smallest part depending on how fast you want the bike to go.
Better yet, you don’t even have to shift. The bike has a computer that senses when you go up a hill or when you’re traveling on a flat surface. The computer will make it easy for you to pedal uphill by adjusting the belt automatically and will re-adjust itself when the terrain flattens out.
That’s what a continuously variable transmission does.
That doesn’t sound bad at all. In fact, having something to do that for you is actually pretty great!
One of the major benefits of a continuously variable transmission is that fuel efficiency can be improved over a normal automatic. Without gearing, the transmission can select the optimum efficiency band and just keep the vehicle driving at that maximum efficiency. It’s just one reason the CVT is so popular in so many cars today.
Another benefit of the CVT is its weight. The continuously variable transmission is lighter than a normal automatic as the metal gears are eliminated. This also plays a role in better efficiency as a vehicle doesn’t have to use as much gas when it’s lighter.
The smoothness that comes with a CVT is yet another benefit. No gears means no dips in power or any hard shifting during acceleration or deceleration.
Ironically, this smoothness is also one of the downfalls of the continuously variable transmission. Mostly because of the general public’s lack of knowledge, cars with CVTs are programmed with shift points to simulate the shifting of a regular car.
Some people just find the shiftlessness of the transmission to be annoying, and many think the vehicle might be broken when they expect something to happen that doesn’t. In a small way, this defeats the CVT’s purpose entirely, but hey, you have to give the customer what they want.
Another big flaw of the continuously variable transmission is its tendency to fail. Not all CVTs are totally unreliable, but it does make sense that a metal gear with teeth or a chain is more durable than a belt. This is also why timing belts have been largely replaced with timing chains throughout recent years.
The general lack of durability compared with a geared transmission also prevents the continuously variable transmission from being used in vehicles with a lot of horsepower.
Trucks, most sports cars, large SUVs, and many vehicles that make over 200 horsepower can’t reliably use the CVT because of its load limit. With many of today’s vehicles being made with more horsepower than ever before, this has limited the transmission’s use to small cars, midsize sedans, and small SUVs.
Technology will continue to improve, and with it, the CVT will also improve.
Toyota uses a starting gear in their new Corolla hatchback. It’s like a normal 1st gear to eliminate the rubber band effect during acceleration that CVTs often have. Above 25 miles per hour, the starting gear disengages and the normal CVT takes over.
The new 2019 Kia Forte will use a continuously variable transmission for the first time. It’s different than most, though. It uses a chain setup rather than a belt, which presumably will help with durability.
The CVT is a heated topic among car enthusiasts, consumers, and manufacturers. Like everything else, there are both pros and cons to having a vehicle with this often understood bit of technology.
I personally don’t like the CVT because of its limited abilities, propensity to fail, and its driving characteristics. That doesn’t mean I can’t recognize and applaud its benefits either. It will become better. It will be improved with time. It will be the automatic transmission that replaces the automatic transmission.
