Son recently bought as used 30 ft. Had new 7000 lb axles under it but thought it was a little light for him. He put new 8000 lb axles under it now and upgraded the springs to 9000 lb ones. He thought the $100 more for the heavier springs was well worth the extra money. They are made a lot better than the lighter ones. He cut the dovetail off and added another 2 ft to it and pitched it a little less so he could at least drive a car one it without bottoming out. Pretty nice now when done. Trailer is just sitting on one axle yet in the picture. He is moving them back to accommodate the longer length.