you'll find 24" with dirtjumpers and skatepark, street-type riders. the old bighit ran 26" front 24" rear for extra manualbility. there's plenty of 24" wheels out there that are unbreakable, as long as you don't mind the weight. a larger crankset won't necessarily be needed, but you will definetely be slower. most 24" bikes run standard gearings. you'll acclerate faster, however.