Hi Doug!
Roberta offered you great advice(thanks Roberta). Also, make sure that you are using cycle shoes that snap into the pedal as opposed to a regular shoe with a toe strap. Pay close attention to your stride making sure not to curl your toes as you speed up your cadence. Many people unknowingly do this as a way of hanging on to the pedals(which in turn can cause the calves to cramp). You may also want to make sure that you are getting enough potassium in your diet since a lack of it is known to cause some cramping in some people. Good Luck!