How a Continuously Variable Transmission (CVT) Works
I have explained what a CVT or continuously variable transmission is to at least a half a dozen people. So, usually when that happens I take the time to write up a tutorial and share it with you guys.
Now, the CVT discussion came up as a result of a broader car discussion in which I was explaining that a Nissan Murano SUV has a CVT transmission – which I really like. But it’s not the only one. There are quite a few vehicles with a CVT such as:
- Mitsubishi Lancer
- Honda Civic Hybrid
- Nissan Altima
- Audi A4
- Dodge Caliber
In addition to automobiles, CVTs can be found in scooters, and even some new bicycles. In fact, the CVT began as a small vehicle transmission and later had to be beefed up substantially to handle large vehicles like the Nissan Murano.
The following is a video of the Variator in a Yamaha T-Max scooter with the case removed. Notice how as the engine revvs up, the centrifugal force changes the ratio of the gearing by simply using the belt.
In this next video Leon Li from FlyScooters.com gives a demonstration of how the CVT works on a scooter.
One thing that is very cool is that CVTs are becoming available for bicycles too now. So imagine getting rid of that old fashioned “10 speed” in favor of a bike that does all the shifting for you automatically.
Here is a video of some guys who are running a CVT on a racing go-cart. Not only can you see how the transmission performs, but you get a look at the actual tranny in action.
For more information, you might check out the How Stuff Works site.
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Zach: Also, centrifugal force is the correct term for any acting force that moves away from the turning force along a radial axis.
As far as I am aware, “centripital” isn’t an English word.
Zach – Centrifugal Force: ” In Newtonian mechanics, the term centrifugal force is used to refer to one of two distinct concepts: an inertial force (also called a “fictitious” force) observed in a non-inertial reference frame, and a reaction force corresponding to a centripetal force.”
Yield9 – Well, you are partially correct. Centripetal is a real word. But it was misspelled by one letter.
John P.
Zach-no such thing as centrifugal force? Depending on what part of the world your in… YES there is. Metre, mile- their both valid words to define distance. Next time don’t jump to conclusions, it makes you look silly and juvenile.
Does anyone have any examples to give for bikes with a CVT setup, or any sites that showcase them? I would be interested in trying them out.
THese would be great in electric vehicles, and it should be centripital force, theres no such thing as centrifugal…
Nice set of videos. The information I have been searching for is how are the pulley’s adjusted? I am assuming that they use a set of springs & weights so that as weights expand through centrifugal force they move a cam or something similar to expand or contract the pulley?
I drove a Nissan Rogue the other day, it shares the Murano’s CVT, yet for some reason Nissan thought it would be a good idea to install paddle shifters…even though there are no gears to change
CVT’s have taken a long time to get to this point of development, and they offer an exciting alternative to the conventional automatic gearbox. The question that begs to be answered is how well do they work in a high performance setup?