My F250 didn't sag all that much, I thought as it was coupled to my 33 foot toy dump truck with a nose height of about 1 inch. slightly curved sections of concrete that break at the joints) I hit the fenders on every 3rd break. I thought everything was doing its job and it was just a rough patch that I happily got through. But you know how in an RV, cabinets hang on the wall (just like your house, except your house never moves) and sometimes you store things in them, and don't forget the built-in microwave over the stovetop. Well you get the idea. Built in airbags, just a 20-25 pound run eliminated hard bumps and dolphins and smoothed the ride so much my wife would actually drive a truck with an RV attached. Worth every penny.