Well when pulling with a truck the wagon is still a farm implement not a trailer but the law says a "pole trailer" transfers non of its weight to the pulling truck. In other words a wagon. But as far as the cops go it had better be steerable because they do write overweight tickets on grain pups and they do not transfer the weight to the truck while they seem to leave the farm wagons alone. so far anyway.

There was a story in the AgriNews last year about a guy who got caught with a loaded grain cart behind his tractor. I'm pretty sure his overload on the grain cart axle caused a $20k fine. Wasn't the tractor axle load I don't think.