Aztalan Cycle Club, as a host track for the Triple Cross series will be running the new AMA SuperMini class at all Triple Cross series races. You can locate the rules for this class in the AMA rule book.  Here is a brief overview of the class. The age group is 12-16 years old riding bikes with an engine size between 79cc-112cc : 2 stroke and 75cc-150cc: 4 stroke. The maximum wheelbase is 52" and the maximum front wheel size is 19" with maximum rear wheel size of 16".