[ChrisH]

Originally Posted by Derek Bessette

There is an idea very similar to this that will work. It has been proven with much higher torques that those seen on a FIRST robot. It is called a CVT (Continuously Variable-Transmission). There are many types of CVT's but the style you are looking at is used on snowmobiles and go-karts.

It would be difficult to build one of these on your own but it definitely can be done. The trick behind these CVTs is that the more torque you apply to the tighter the secondary will squeeze on the belt. This creates more belt tension.

Hope this helps.

When I was in college our Mini-Baja team used this sort of thing. It worked pretty well for that. Depending on how the tensioning happens you have to make sure your shafts are in the right speed range, but you know how to do that right?