Mud Flaps

stufarmer wrote:
do you thing Rock Tamer Mud Flaps reduce your Fuel economy while towing ??

I don't "think", I KNOW they do.

Yes, really, they do.

I transport RVs part time and run the same route time and time again: Spokane, WA to Pendelton, OR and back.

I track my fuel MPG religiously.
Early this year I bought a set of Rock tamers and started running them, not long after I started hauling RVs again in late winter. (I took the winter off)

I noticed my MPG was down about 2 mpg when running empty, and about 1.5 mpg lower when towing. I chocked it up to winter fuel blend. Spring time rolled around and my MPGs were still in the toilet, so I pulled the Rock Tamers off. MPGs went back up to where they had been prior to installing the Rock Tamers. This is on my 06 SRW.
The may not have as big of an impact on a DRW, since the DRW will "shield" the flaps from acting like big sails from air flowing under truck.