Rear Rock Guards...An Interesting Observance Today

[2gypsies1]

We had to travel in rain all day today so for lack of something to do I did a study on motorhomes traveling in the opposite direction with brush-type or solid rear rock guards and those with none.

The ones with both types of guards threw water high onto the towed vehicles. Those with no guards tossed water low at tire level of the towed vehicles.

This got me thinking that when we went to Alaska we actually saw folks removing their rock guards claiming they were throwing stones at the hoods and windshields of their towables.

We have no rock guard - just flaps behind each wheel. We didn't have any rock damage to our towed on the Alaskan trip. Interesting....

[obgraham]

I've watched these a lot. If the shield is mounted hanging just above the road it drags as you go over bumps, etc., and kicks up rocks and muck. Just look at the beat-up bottom for proof.
If it hangs too high the whirling draft created behind it sucks road crud up also, something like wing-tip vortices on airplanes.
There may be a sweet spot, and it also depends where it is hanging in relation to the back of the coach. All too complex. Bye-bye!

[dougrainer]

I am a RV technician and Master Certified. I have had scores of my customers relate their experiances. I have had 2 customers that purchased from CW. They each purchased the standard hard rubber first and had problems with debris on the tow car. They each got CW to exchange for a broom type and had the same problem. They then got their money back and purchased the specific Rock guard that mounts ON the Tow bar. THAT solved their problem. From what I have observed in the past 25 years since people started putting them on---THEY ARE USELESS, BUT, BOY, DO THEY LOOK GREAT. AND they make me money when they get bent and torn off going over curbs and such. Next time you look at a Rock Guard, Notice how many open areas there are at the top and how far it sticks from the ground (most due to air suspensions on Diesels). They are installed by both the OEM and the aftermarket because people wanted them, NOT because there has been research by OEM's or anyone on their effectiveness. Doug

[gbopp]

That's a very interesting observation. I'll have to watch next time I'm driving in the rain.
I wonder if anyone has a 'scientific' explanation why this happens?

[robatthelake]

Not only that ,the way they mounted Ours to the Fiberglas resulted in tearing it Half off!

[obgraham]

I agree with your observation. And I got tired of bashing my rockguard on the ground and having to remount it -- till I realized I was better off without it.