Racers in the 20" class are grouped with others of the same relative age and experience levels; Novice, Intermediate, Expert, Veteran, "A" Pro, "AA" Pro in the ABA; Rookie, Novice, Expert, Elite Masters, "B" Pro (Superclass) and "A" Pro (Elite) in the NBL. They range from 5 & under Novice to 28 & over Expert in the ABA and from 5 & under Rookie to 35 & over Expert in the NBL. Cruiser Class (bicycles with 24" or greater diameter wheels) and the girl classes are not divided up into skill classes, only age classes in both the NBL and the ABA. The Cruiser class age brackets for example range from 9 & under to 51 & over for males, 10 & under to 41 & over for females in the ABA; and 9 & under to 55 & over males, 10 & under to 40 & over females in the NBL.