Mud flaps with custom drop brushes to protect your trailer from rocks coming off your tires

As you may know we have an Airstream that is made from beautiful, but relatively soft and malleable aluminum. The Airsteam does have rock guards, but those dent as well, and we would rather not have our rock guards dinged with rocks. Well, any more dings, because we already have some.

I put the WeatherTech no-drill mud flaps on the truck before we got our trailer, thinking the mud flaps would be enough to protect the trailer's rock guards. While the WeatherTech no-drill mud flaps are very good, they don't stop some of the rocks that get thrown from the tires.

We had to come up with some way to protect our Airstream from rocks. There were several requirements I wanted the solution to meet. I didn't want to drill into the truck and I didn't want to use a product like Rocktamers, Towtector, Rockstar, Roxter, Luverne, etc that are hitch mounted, because I don't want yet another item to deal with when hitching and unhitching. Since the exhaust pipe on the Duramax sticks out so far, the solution also has to allow the hot exhaust to pass through it, which eliminates most solutions.

We already had the WeatherTech no-drill mud flaps on the truck, which are very good mudflaps. Don't let the 'no-drill' fool you into thinking they are flimsy or may fall off. The mounting system is so good, that you don't have to worry about them coming off, they won't.

I like the drop brushes like you see on the towtector, so I decided to go that route. I'll save you the many hours I spent looking for a hang down brush that could be mounted to the mud flap. They are very hard to find.

The brush needed to be at least 10" drop length, but longer would be better. I found a brush made be Industrial Brush out of St. George Utah. Even better, they make a drop brush kit for RVs. I ordered the kit, which comes with 2 x 4' sections of 11" drop length brush and the mounts. Great, so I thought. When I got the kit, I saw that the mounts are horizontal mount, not vertical mount. Ugh. So I called IBC and the nice woman who answered the phone said yes, that they have vertical mount holders, but they don't sell them to individuals. I'm not ashamed to admit I begged her to sell them to me. Eventually she did, but it took several phone calls to get it done. I don't recommend this route to get the correct mounts. She did tell me that the vertical mounts can be purchased from McMaster Carr, which is what I would recommend. I suggested to her that they offer two different kits, one with vertical and one with horizontal mounts, but she said they weren't interested.

I cut the mounts to width of the mud flap and bent them, ever so carefully in my vise, to the curve of the mudflap. I also found a 1" strap of aluminum at Lowes to make a backing plate for the screws holding the brush mount to the front side of the mud flap, as I didn't want the mud flap to crack and the screw to pull through.

The brushes are mounted to each mud flap with stainless pan head machine screws with stainless lock nuts.

These rock deflecting drop brushes have been in use for about 10,000 miles with zero troubles and no more dings in our Airstream rock guards. I don't have to removed and install anything when I hitch and unhitch. They just hang there and deflect rocks all day without complaining.

Kit from IBC ordered on Amazon:


Vertical mount vs horizontal mount. You can also see the slight bend in the extruded holder.


Backing plate and lock nuts:


Unused 4' section of drop brush:


Back side screws:


Finished product: