[radioranger]

Video on you tube seems pretty convincing, i guess anything that eases the transition form flat to tapered really helps,I have an old shortbed ranger and am thinking of trying to make a bed cover that extends past the tailgate a foot or so to make the truck seem longer , and use the same thing under the rear bumper to bring the airflow up gradually , understand you only have to cover the back one third or so of your bed to get full benefit of cover , so a 4 X 8 sheet of plywood cut to fit across the bed and let it hang off the back a bit , easy and cheap to test, any taper past 7 degrees down though will cause flow to separate, that's why all these new crossover vehicles have a tapered roof.