Change Ringing Speed 

This is a great image of what happens when we ring a bell "full circle".  We start with the bell mouth up and pull on the fluffy bit (sallie) for what we call the "hand stroke".  After the bell rotates almost 360 degrees we pull on the end of the rope to accomplish the "tail stroke".  

The clapper actually hits the leading edge of the bell just before it becomes vertical and then rests on that edge.  On larger bells it can take about two seconds between strikes of the bell.