I was driving my truck last week with the windows down and radio turned off enjoying the warm weather and the sweet sound of my Cummins exhaust note. As I began to slow down for a stoplight, I heard a light tapping sound coming from the passenger side which seemed to be in sync with tire rotation. To be honest, it sounded just like a tire with a nail or a rock stuck in it. After getting the truck home, and lifting every wheel off the ground and rotating them, I have been unable to find anything lodged in the tires. The truck continues to make this sound and from additional observations, I have noticed that you can not hear it at speeds below 20 mph, it is most prominent between 20 - 30 mph until it disappears to the hum of my Toyo M/T's. What could be causing this annoying ticking sound? I am not experiencing any vibrations or any changes in the ticking when turning left/right or while braking, it seems to be only speed related. Any advice on what I should look for next? Thanks in advance!!