Motor Vehicle Maintenance & Repair Stack Exchange is a question and answer site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

The title basically says it all, but I am the most interested in what the rollers actually do?

share|improve this question

Summarizing my own answer to Engine braking with an automatic transmission:

Using the pictures from the Nissan CVT overview site:

Nissan's summary picture is quite good.

You can see that there are two variable diameter pulleys connected by a very robust belt. This theoretically allows for an infinite number of gear ratios. Practically, there are plenty of engineering and human interface limitations that reduce infinity to a more manageable set of presets. There is a finite resolution of the pulley adjustment mechanism that allows the engine computer to direct the transmission. This means that, while not quite infinite, you probably have many many more effective gears settings than the five choices I have in my car.

share|improve this answer

The rollers allow you to continuously vary the diameter of the driving pulley. As the speed of the driven wheel depends on the ratio of the driving and driven wheel diameters, you can see that the rollers can provide try with a continually varying ratio.

Pretty certain we have a few questions on this topic here. Have a search around.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.