A 24-inch bike for kids is for heights between 4’1″ to 4’9″. The size range for a 24-inch bike for adults will vary based on the model and manufacturer. For example, the Tern Node folding bike has a height range of 4’10” to around 6’5″. The Yuba Kombi cargo bike fits riders from 5′ to 6’6″, and the Electric Bike Company Model A 24″ version fits riders 5’2″ and under.