[skyking]

My travel trailer design depends on squatting down to reduce frontal area and air underneath. it has been suggested by some that a trailer only 6" off the ground with a smooth belly might be worse off than a higher one in the drag department.
I imagine a detrimental sort of "suction", more like a nightmare
If it is proven that I am being paranoid, I will "keep on keeping on" with it, and use the vehicle's VSS signal to trigger a raising event at 20 MPH or so.
The truck I will push down to a practical 8" or so in front. Low enough to help, not low enough to ding on a common curb.