When you put on larger mud flaps behind your dually's ......
You have to be careful when you back up so you don't push the flap against the tire. The rear tires will grab the the flap and run over it, ripping it away from the mounting bolts. Backing into a low curb, backing into a small depression.
I've torn mine off twice. Fortunately, they can be screwed back on, even though the holes become slots where they ripped open.
I bought a full size truck mud flap for just $7 or $8 at a Freightliner shop. Cut them exactly in half, and mount the nice chrome plate at the bottom.
Bill (Dune'r) & Helen
Last of the Chieftains, 2004 39T, W22, Banks Headers, Koni's, Safe-T-Plus, SMI brake
2013 Lincoln MKZ Hybrid towed 4-down