Ok, I have a problem and I don't know how to fix it. I need a ladder rack on my Silverado 2500, but everytime I put one on the buffeting of the wind over the front cross bar causes the roof to vibrate and hum horribley. I have tried two different racks ont he truck, and both do it. One has a square bar, and as you would think its worse. The one with a round bar is pretty bad to. At speeds over about 35 or 40 miles per hour the hum gets so loud that its pretty unpleasant. You can put your hand up aganst the ceiling of the truck and feel the roof vibrating very strongly.
Basically the roof of that truck is very flexible and any air tubulence is going to cause it to become a large sound diaphram. My Colorado has ridges molded into the roof to make it more rigid, but the Silverado is basically a plain flat surface. I have considered adding a wind deflector like a lot of people pulling fifth wheels use, but man that a big ugly device. I have also considered making the roof more rigid by glueing some heavy rubber strips to the roof. I was thinking the rubber used on the keel of boats to protect the fiberglass on boats that are routinely beached might do the trick. Probably about 6 or 7 such strips run from front to back. (that would be a pretty pricey solution, and I don't even know for sure it would work,)
Any other suggestions?