big pro tip: if you have a ladder rack on a truck and it's making the WORST FUCKING WIND NOISE in your entire life, the solution is simple. You wrap some rope around the front bar like the bit you can see on the frontmost upright on my shitrack. Wide spaced loops. I went from "oh shit did I spend a hundo on a shitrack and a hundo on new steel to make the truck deafening above 50MPH?" to zero added noise just by wrapping that spare rope around the front horizontal. It breaks up vortex shedding, in the oilfield they call similar structures in subsea 'strakes'.