maurice-r wrote:

I respect you guys who have driven tens of thousands of miles! I had not seen any air deflectors that were as gradual as the one I made. I wondered how effective the short but sharp angle style is. Such as two pictures that have been posted in this thread.

If I may ask for clarification? Of the comments of little milage difference, (both your experience and from hearing others report) are most of the air deflectors of the short length and sharp angles?

Could it be possible that a long shallow angle deflector might help milage better than a short sharp angle?

Our family members also drove a Ford F150 pulling a car hauler empty except for a small cargo trailer ON the car hauler - so top of small cargo stuck up at the 9' mark. His fuel milage was much lower than with no trailers. (I had offered to make a quick "camper shell-air defelctor" out of osb ply before we left but he said his bed cover prevented that.) He got better milage on the eastbound trip when he pulled the car hauler with a kia sedan on it and another family member drove his own F150 pulling the samll cargo.

Again I say, all of my information is from the dashboard computer, so it is not scientific.