We have a wide range of kids bikes for our bike tours in Hanoi Vietnam. Our small bicycles are used for both boys and girls. There is no difference between boy bikes and girl bikes. The bike frame is the same – Children’s bikes are sized by wheel rather than frame because it’s the wheels that determine the proportions of the rest of the bike. Make sure your child can operate the brake and gear levels comfortably, and that the pedals are positioned for safe stopping.