On July 17th, 2018 we learned about

Making sense the inconsistencies of cars’ mud flaps

Kids are supposed to ask why the sky is blue, what happened to the dinosaurs, and maybe where babies come from. My five-year-old, apparently content in his knowledge of such things, has instead been wanting to know more about mud flaps on cars. What are they for? Do they help a car drive faster somehow? The thing that was really bothering him though, was if mudflaps are useful, why aren’t they part of every car and truck on the road?

Mudflaps have probably been conceived a number of different times throughout automotive history, but Oscar Glenn March of Jones, Oklahoma is generally credited with inventing the products we know today. Unlike the side-mounted “anti-splashers” patented by William Rothman in 1922, March’s flaps were built and put into immediate use. March worked in the motor pool on Tinker Air Force Base during World War II, and realized that they needed a way to protect sensitive radar equipment from mud and rocks when it was hauled on flatbed trucks. The flaps were originally made of canvas which has since been replaced by rubbers and plastics, although March’s original bracket-mounting design is still in use today.

How functional are rubber flaps?

In addition to keeping your radar equipment clean, mud flaps can also protect the vehicle they’re mounted on. In areas with lots of rain, snow, salted roads and of course, dirt and mud, the right mud flaps can help prevent dirt and rocks from damaging the paint on fenders right behind a car’s wheel well. Beyond one’s own car, mud flaps can also help cut down on how much dust and water your vehicle will spray on anyone around you, which is part of the reason they’re legally required on trucks in many states. These vehicles’ higher frames and larger wheels makes them prime candidates to launch more rocks and water at other drivers, and so properly-sized mudflaps trap those materials before they cause trouble.

Of course, not every car today has mudflaps, which raises the raises questions about how valuable they really are. A piece of heavy rubber can’t be that expensive, so why don’t all cars come equipped with mud flaps by default? Many modern cars do have some extra plastic molded behind their wheels, but why not use the flexible flaps trucks are required to use? This is a trickier question to answer, as there’s no single authority declaring that mud flaps be excluded from modern car designs. Sometimes there are concerns over improperly mounted mud flaps, which require holes be drilled in a car’s body that can end up leading to rust damage. Other people argue that the flaps cause a small amount of aerodynamic drag, making them slightly less efficient to drive with. Finally, there’s the issue of aesthetics— some people think they look great on their cars, while others think they’re simply eyesores that will get bent up against speed bumps. There may not be a single “right” answer to this, although that won’t stop some people from asking questions.

Source: Who Invented the Mud Flap?, Fruehauf Trailer Historical Society