Problem with new 2013 silverado
 

when i drive on gravel roads which i have to everyday to get to work alot of rocks shoot up and hit the truck what can i do to stop this aside from going slow to hear no rocks hitting i have to be going 20km/hr or less any suggestions are apprieated i already have mud flaps

You are not going to stop the rocks from hitting your truck so what I did was have the rocker panels under the side of the truck sprayed with bedliner, like Rhino liner or who ever. Sprayed from the front wheel well to the rear wheel well. I did it 9 years ago when I had the bed sprayed on my 04 and still looks good, no rock dents.

Protect your vehicle's paint with Scotchgard

Try replacing your molded mud flaps with bigger and longer mud flaps.
Replace your tires with a tighter tread pattern so your tires don't pick up the stones.
Treat the under side of your truck with a rubber stone guard.