Agreed. As a 20 year+ street skateboarder, I can tell you that even with larger and softer urethane (85-90A) wheels, a pebble the size of a tic tac will send you to ground rapidly. The key is to over time develop skills of controlling weight on your board. I suppose this design could be modified some, but more likely that the driver/rider will need to learn some skills from skateboarders :)