there is a third kind of kid that rides bicycles, my son when he was little would go down a hill on his bicycle ( with training wheels ) at 1 mph and no faster. I bought him a go-cart for Christmas and he hardly even rides it. dad ( 52 ) kicks up a little dirt on it some times, I can't get him interested in sports or anything that is physical. He likes to play video games all day and doesn't like to get outside much. Sometimes i think these kids are crazy for what they are doing on bicycles these days, but when your young sometimes you have to get out there and push it to the limit.