Constantly Changing Gear Ratio

[BasketDaN]

I have heard that this concept is already starting to be implimented in cars (constantly changing gear ratios), is this true?

[wolram]

it was done years ago by DAF, useing two pullies that expand or contract joined by a belt.

[wolram]

it was also tried in F1 but was banned

[J-Man]

For googling purposes.... this is commonly called a "Continuously Variable Transmission" or "CVT".

[russ_watters]

I believe that there are several production cars that use it. The gas/electric hybrids I think.

[BasketDaN]

What became of it/ why is it not more popular?

[J-Man]

This link is 2 years old, but still relevent, and I think you'll be interested.
http://www.edmunds.com/ownership/techcenter/articles/45104/article.html

Some drawbacks of CVTs:
-belt-driven orientation
-size
-weight

(You might be interested in knowing that CVT's have been around for nearly 120 years.)

[BasketDaN]

Ahh I see, thanks. Does anybody know if this is the only way CVTs are currently made?

[LURCH]

Originally posted by BasketDaN
Ahh I see, thanks. Does anybody know if this is the only way CVTs are currently made?

AFAIK, belt-driven CVT's are the only type being put in automobiles. However, I do recall seeing a bicycle that appearently used a CVT which employed centrifugal force on weights attached to the hub of the tires.