My sons birthday is next sat and Im torn on which size bike. A few days ago, we went to LBS and he rode the Specialized Rip rock 20. He liked it. That said, at the moment I think it fits perfect, but I feel in a year, or by next sept/oct, he'll be outgrowing it. So im thinking of doing a 24" Scott Roxter. It has the shortest standover height then most other brands and its the lightest. Id hate to do my son a disservice by putting him into something to big, but then again, I really don't wanna buy a bike very 15-18 months. Anyone have similar situations?