The AMA Pro Flat Track Grand Nationals event at the Knoxville Raceway has been cancelled. There will be no make up date. If you purchased tickets send them to the Knoxville Raceway, P.O. Box 347, Knoxville, IA 50138 along with a self-addressed stamped envelope for a refund. Knoxville Raceway officials report that track conditions have been determined as unsafe for riders as a result of rain.