Looking at the bike, the proportions seemed weird at first and then I realized it's an upright hybrid, with a high handlebar, but without the swan frame you might see on an adult version. It has relaxed angles and low gears, and I'm sure it's no lightweight. It's a recreational bike, not an athlete's training bike. I sort of doubt drastic changes would make him happier with it, or faster. What are you expecting him to keep up with? Can you slow yourself down?