Thanks, adam and Nitro Fumes. I figured thats how it worked, just cant imagine why\how the spinning would cause the clutch to expand and engage the bell. I'll look up centrifugal clutches.

Whats the advantage of having a 3 shoe clutch as opposed to 2 ?

My car likes to idle high, and it wants to race off unless I apply throttle\brake trim. This effects the way the driving characteristics because the car wont coast when I let off the throttle, instead the brakes come on and it stops. Any suggestions ?