The air dam I made for my truck is about 11 inches from the ground. I wanted some clearance for snow and some light off road trails. I made it into sort of a delta shape that angles and curves back to the wheels.
97 Ford F250HD
I made it a couple inches lower than the front axle, except for the differential, that hangs down a few inches. I haven't narrowed down just what % increase it gives me, but it is noticeable. I really need to make the front wheel miniskirts and finish the under-axle belly pan I started.
