Four-wheel support from the rear training wheels and 18-inch main wheels helps kids practice balance while learning to ride this bicycle on wood, cement, asphalt, or brick roads. A carbon steel frame and durable multi-layer rubber wheels support a 121-132-lb seat capacity for riders 47.2-59.1 in tall. The handlebar and 24.5-29-in saddle height adjust so the 50 x 21 x 30.7 in bike fits growing children. A hand brake and coaster brake give two ways to slow down, and the 9 x 6.5 in saddle and front basket add comfort and storage for small items.