What's the widest ratio range for a CVT?

[f_nosferatu]

Hi!

I'm designing a human powered vehicle and I need to use a CVT (Continuously variable transmission) in its drive line. I want to know the widest range that the speed ratio of a normal CVT (One that's not very big, heavy, or expensive because our vehicle needs to be as light and cheap as possible) could fall in. Can anyone help?

 

[mender]

The Nuvinci is .5 under to 1.75 over. With the addition of some common concepts that can be extended dramatically. How much range are you after?

 

[f_nosferatu]

The more the merrier! Actually, my design so far is based on a CVT with a ratio varying from 1/3 to 3, but I don't know if this is practical or not, and I can still use a range wider than that.

 

[Topher925]

Most CVT designs are not limited in a gear ratio based on their principle of operation. Like most transmissions, your gear ratio range is only limited by what it is designed for.

BTW, CVTs are by their nature big, expensive, and heavy. You can also add high maintenance and less reliable to that list as well.

 

[Abninfamy]

This is off a flier from Quality Drive Systems concerning the Comet CVT 790 series

Pulley Ratios:
High: .54:1
Low: 3.38:1

and for 770 series
Pulley Ratios:
High: .76:1
Low: 3.95:1

Hope this is the info you're looking for.

Comet CVTs are relatively inexpensive and small, it's what we use for our mini-baja applications.