The 20-inch frame accommodates older, taller youngsters than the 16-inch frame. In addition to the coaster brake, these bikes may incorporate hand brakes to enable the youngster learn to use their hands to slow or stop. They are more difficult to ride due to their larger size and heavier weight. The larger frame is also more stable, which helps to minimize the risk of injury when riding over rough surfaces. The bigger wheelbase provides better traction in snow and mud, while the increased tire width offers greater coverage when spraying water for cooling during hot summer days out on the trail. These bikes are best for young riders who have not fully developed their bodies or mastered their skills yet. They are often built with lighter-weight materials used by adult cyclists who are just getting started outdoors. Bikes in this category are usually sold as pairs. One bike will be given to an underage rider for his or her own use while the other keeps up with the family trade shop. These bikes are commonly found in black or white with red accents. They typically come with simple flat tires that are easy to repair or replace. You can find adult bicycles built for much longer distances. These usually have thicker frames, wider wheels, and stronger brakes.