I was towing/hauling 7600lbs across the back roads of AL, cruising at about 65mph. I averaged about 13.5mpg during the trip.

 

I have been getting 12-13 pulling my 5th wheel (about 11,000#), usually at 60-65. 27K on the truck (4x4). Above 65 milage drops off quickly!!

 

my lie-o-meter tells me im 2-3 more mpgs than i really am, i do the same thing gtx, when i fill i let the nozzle stop its self and wait about 20 seconds and fill it again and its the same thing everything so my hand calculations cant be that far off. i am thinking about getting a CAI and im curious to what the meter will tell me then being that sereguial said it changed. why would they put a meter on thats not accurate?

 

Ifill mine till I can see the fuelin the neck just below the top, it takes awhile because of the foaming. I need to do the tank mod one of these days.

 

I got 12.5 when I moved from CO to MN. I was pulling a car, had 2 engines and a transmission in the box plus a lot of other stuff so I had the cross section of a semi. I looked like homeless guy with all the stuff, most of which was my roommates. I was doing 80 by the way. My roommate scheduled a flight too close to a wedding.

 

Hey GTX, Speaking of tank mods, I have nothing but good to say about my TransferFlow in bed tank. Below is a link to their site and feel free to ask whatever. http://www.transferflow.com/index.html The pic is of my in bed 50 gal. aux tank. 84 gallons will take me a long way, but it's a drag fillin up!

 

Ihave 2700mi on my '07' quad cab 4x2 .. pulled my 8-9000lb 5'r on mostly flat roads (never downshifted or lost speed) with moderate wind and got 12.6 hand calc.. 15 on the l-o-m .. l-o-m is always 2 - 3 high.. I'm getting 17ish empty.. I've never towed anything so effortlessly.. I'd always heard the guys talk about setting the cruise while towing RV's but had never been able to with my 5.9l gasser.. now i can relax..lean the seat back.. turn on the DVD player and pop open a cold beer! (kidding of course)

 

Pullin my 5000# off road popup through the mountains of Central Montana I can maintain a little over 13.5 mpg, but I only have just a hair over 2000 miles on the rig with no mods. Tonneau is on the way and I am expecting that to have a small effect.

 

I pulled my 8500 -9000 lb travel trailer to the coast and back twice now (500 miles round trip). I start out in the foothills of SC and half way through the trip I am on flat land. The first trip I ran 70 mph got 10.5 mpg going and 9.5 coming back. Second trip I ran 65 max I got 11.374 going and 11.16 coming back. My lie o meter was off from .8 to 2.0 mpg until I just installed a Quadzilla XZT now it is of 3+ mpg, optimistic of coarse. [:@]I just did a trip to PA, NJ, and back to SC with the bed loaded full of luggage, I got 18.3 mpg for the trip running 70 most of the way.

 

I think the over head MPG lies a little bit, It seems to be the case with the new Dakotas. i get better mileage than the overhead displays. Calculate it by hand and compare it to the over head mpg. My father inlaws 06 cummings I6 has been getting 20 mpg highway WITHOUT hauling or towing. I'm very jelouse(SP) I'm lucky if i get that on the highway.