like multiple gears and hand brakes instead of coaster brakes. Sizing charts are a good place to start when choosing a bike for your child, but not a definitive answer. Once your child is over 4’10” (147 cm), they can ride an adult size bike with 26, 27.5, 29 or 700c wheels.http://www.caritol-sport.com/k....ids-and-adult-bicycl