Dick1172762 asked on the shout box-what are mud flaps? Well for the younger generation it is a piece of material (rubber,metal or plastic)that went behind the wheels to protect paint from mud,rocks,etc.you see them on big tricks mostly nowadays.the one that craiggarrett1 is referring to taper back to better blend in with fenders(commonly called spats).most cars now are style at rear of wheel well to do the same job mud flaps do.on big trucks they keep try to limit rocks flying off of tires and hitting cars behind.