The answer lies in the tire and motor. The smaller and less tread the tires have, the harder it will be to traverse dirt terrain with the kart. Also, if the cart is not powered by a motor, and the kid has to pedal, it will not fair well in dirt, although it will depend on how much the child pushes on the pedals to make the thing go. You also want to consider how high off the ground the body of the kart is. Most of the time, the kart will do best sticking to flat, hard ground.