I do all my work in my driveway. My driveway is not a smooth concrete finish, but rather comprised of bonded (not loose) gravel rocks (not sure the correct term). Bottom line, is that the jack does not roll smoothly on it, and when I'm jacking up the car it does not always jack smoothly as the wheels have to make their way over the small stones. I could resolve the second issue by using some plywood or some such, but I am wondering if it would be feasible to use a hard rubber instead? Anyone heard of this?