I pulled my travel trailer about 1250 miles this week from Green Bay, WI to the Grand tetons, and only returned 8.6 mpg. It weighs a little more than 8000lbs and is thirty feet long. Hit some head winds in South Dakota and only got about 7.8mpg, but usually averaged about 8.9mpg with little wind. Cruise was set for about 67mph.

Does this seem normal?

My2011 Ecoboost averaged about the same with this trailer. And both this 6.7 diesel and my Ecoboost average about 19mpg empty on the hwy

 

Do you know what your average was before you hit western Montana or wyoming? Just curious as to what it was before you hit the bigger mountain areas.

 

Mastertinner, your MPG sounds a bit low. I get around 9.5 MPG pulling 11K through the mountains in Colorado.

 

I pull a 30' Airstream weighing in at 8k and find my MPG ranges from 12.5 in more hilly country to 15+ in more flats with little wind. We put a lot of miles on and this has been consistent whether we are traveling through Florida or western states. Drove to Alaska 2 summer ago also. I find a pretty consistent 13.5 to be my average. I pull with a F-350, SRW, short bed 6.7 diesel

Roger from NJ

 

I got 8.9 today going thru the catskills heading to maine today, but that is pulling my 5th wheel.

 

​​​​​​Highest mpg was in WI. About 9.6.mpg . I was hoping for more, my trailer doesn't seem very aerodynamic, but I feel I should get better than my f150 did.
I probably also have about a thousand pounds worth of tools and camping supplies in the bed. I'm sure that affects it a bit.

My trailer is a 2013 puma 27rbss. Truck is a ccsb 4x4 diesel with 3.55 gears and 18" wheels. New air filter, oil change, and feel filters before trip. Tires at 75psi on truck and trailer

 

That seems low compared to the mpg I have seen towing my 2012 F350 from Washington State to Jackson WY. Three large passes in between and never seen my mileage drop below 11. Towing 13,000# 5th wheel. 3.55 gears. Might be aerodynamics of your trailer and bucking head winds which will drop your mileage, but overall travel distance one would expect to see better results from the 6.7.

 

My experience is its not the weight of the trailer but the aerodynamics and how it is set up when pulling with a diesel. I have pulled a 6000lbs enclosed trailer that was "96 wide (12' tall) which got worse mileage than my 16000lb 5th wheel with a back hoe. Wind resistance trumps weight at those speeds in IMO. Any type of x wind just kills your mpg.

 

Sounds about right. I get as low as 7mpg loaded in the mountains. Put more fuel in it and continue.

 

I'm pulling just 900 lbs less than you and drive 62-63 MPH. I have the same 3.55 and 18" wheels. Mileage on a trip driving all the way around the USA was 11.7 and headwinds were not favorable most of the time. I was at 13 for the first quarter of the trip, then the winds kicked in. I thought fine, I'll get that back as I make my way back, but the wind changed once again and was getting a steady hard wind across the starboard bow across several states. A similar trip, but fewer miles, the mileage was 11.3 with the wind again being the problem. I think that you would get the same results if you absolutely never, under any circumstances exceed 63 MPH. I have seen drivers constantly playing with the throttle, speeding up to pass for example, and then have far less fuel economy.

 

Seems low, but there are so many things that affect fuel economy. Fuel quality, tires, if you did a lift, gears, how fast you go, how much you idle, trailer profile, how the trailer is loaded.... I drove from South Florida to Alaska last year with a 7500# cargo trailer - finishing up my move to AK, v-front, 6' interior height. I was about 16k pounds overall. Truck is in my sig. I got anywhere from 12-14 on the highway. Speed and wind were my biggest factors, around 13 overall. On the way down without the trailer, I got 18 mpg. I had a couple tanks of 20 mpg, but most were closer to 18 mpg. Especially when I hit those 80 mph interstates in the L48....

Can't compare this to a EB F150. Truck is heavier, has more hp and tq and you might not realize it, but you use it. I drove a Uhaul with Ford V10 in it... I was 10k pounds overall - 6 mpg... That was painful when gas was $8 a gal in rural Canada.

 

I'm a pretty conservative driver. My highest tank empty has been about 22mpg. The start of my trip i had the cruise set at about 57mph on a newly paved 55mph speed limit hwy, and never hit 10mpg for the 50 miles I was on that road.

 

Well I pulled the tt over a 130 mile trip from Jackson, WY to West Yellowstone, MT. Went over the Teton pass (first time over any mountain pass) and managed to get 10.7 mpg. Either my truck likes hills, or it just decided to really do good on fuel. Speeds ranged from 55-70 mpg. I pretty much drove the speed limit. except over the pass and never drove over 70 mph.

BTW these trucks have an amazing exhaust brake. I was able to go down the pass (10% grade) at 25 mph without ever having to touch the brake in 2nd gear.

 

I have found the same things as post above. The cargo trailers with the square fronts are just like pulling a parachute. I add a vnose to my smaller trailer and got 15% increase in fuel economy. My 18 foot cargo with the square front gets lousy mileage whereas my 20 foot camper with curved front does pretty good. Wind and speed play hell with all 3 as far as fuel averages but the 6,7 doesnt know any of them are back there as far as power

 

I just pulled my 13,000 lbs 4H GN trailer from Salt Lake City area to West Yellowstone and made 4 day trips into and out of Yellowstone and returned home and avg 10.6 mpg.
My truck is Leveled and wears 35" Toyo AT's and has the 3:55 rear end. I drove 70 mph on most of I-15 and the speed limit in the park

I find weight is not much of an issue. 8,000 lbs empty or 13,000 lbs full of horses, mileage is the same. It has more to do with drag of adding 4 more tires and the wind resistance If I fight a headwind, I can easily loose 3-5 mpg

5th wheels with square front ends and that have higher profiles, awnings and such hanging to their sides will have more air drag than my horse trailer.