5th Wheel Tailgates/Fuel Efficiency

[JJump]

Last October I purchased a '93 D350 ex cab dually/30 ft 5th wheel combo. The previous owner ran the unit without the tailgate installed but with a 2x6 attached across the back of the bed at the floor (this held the bed mat down). He included the OE tailgate in the deal & shortly after the purchase I reinstalled the original tailgate. A couple weeks later I took the combo out for the weekend, leaving the factory tailgate installed - no problem hooking up the trailer with the tailgate down & raising it before getting underway. But I did notice quite a bit of turbulence in the bed while towing-enough so that the bed mat started flopping around in the back of the bed & tearing at the hitch cut-outs. I tried weighting it down with the dunnage used for chocking/leveling the trailer, but the mat pulled out & continued to flap.



I've noticed the 5th wheel tailgates around and see most are constructed with louvered vanes directing the airflow downward. Others I've seen just covered with expanded metal. In all cases they are designed to allow airflow through them, which indicates to me that there might be some real efficiency/drag reduction to be gained here.



I would appreciate any insight the membership could pass along regarding these observations.



Thanks for your time!



Joe Jump

St Louis

 

[B.G. Smith]

I towed my 5th wheel with the original gate before I got the v type louvred gate. Only big difference I see is that it is easier to hook up/un hook with the v type. I too have noticed that there is a tremendous amount of air going down into the bed. I think with the louvred gate or no gate, the air exits the bed and hits the trailer front below the 5th wheel resulting in no loss of drag. Some of the air also goes under the trailer as I can see lots of mist coming out from under the trailer back near the front tires when I am driving on wet pavement. I think that if you could cover the bed and make the air go around the trailer you might have less drag but can't prove that. A wing on top of the truck might help keep some of the air out of the bed. bg