My son is autistic and has some muscular problems. He will be 11 soon and he wants to learn to ride a bike. He has a 16 inch bike but he is so tall he cant get comfortable on it. He has come a long way recently in his physical therapy and his therapist says a bike can help him build muscle on his legs. I bought a bike at walmart and a set of training wheels for a 20 inch bike but they weren't compatible with the bikes walmart sells. Any feed back would be greatly appreciated.