It's been talked about before but we just returned from a short 2,500 mile trip and no huge mountains except the big hills in PA. and we averaged 11.5 towing and was happy with that. What are you averaging these days??
We have about 26,000 on the truck now.

Steve

That's what I get towing flat easy highways & mine has 102k miles. On average hills, wind, heavy right foot I get about 10 mpg. I've gotten as little as 6.5 bucking a head wind (won't do that again, we'll stop) & as much as 11.5 & typically drive 65-70 mph, could probably get 11-11.5 consistently if I'd slow to about 60, but that's just way too slow for me.

We average about 70 and try to always stay at that or under for safety. The worst mileage I ever got was when we had the 2011 ford (nothing against Fords, it was a great truck and loved it!!!) headed to the service center. I was in Ohio with about 20-25mph headwinds and the dash was telling me I was getting 6.1. Rethinking the trip at that point but RW was paying me for my fuel to deliver to service center so all was good!!!

Pulling up to the rally from Nashville I averaged 8.5-9mpg with about 30% fresh and empty grey+black. Returning I averaged 10.2 with some very significant head winds and rain also 30% fresh and empty grey+black. Yup go figure even with an elevation gain of about 1,000 feet from Shipshawana to Nashville. Cruise set when possible @ 62 both directions.

My TV, F-350 dually diesel, has about 66k, new tires and regularly serviced.

Before adding roughly 2,000lbs with upgrades, mods and supplies, I was consistently above 10mpg.

One other data point I can offer would be not towing I'm in the 14.5mpg range.

The last time I towed was to the rally last year. I run between 65 and 70. Mileage for the 5000 mile round trip was 10.5 mpg this was going from sea level to 11000 ft through Colorado. I have 20000 m on the truck and empty running 80 mph on the highway I get 18

We don't use the truck much except for towing but when we do it tells us we are getting an average of 18.5.

I want your truck at those mpg's

At 70 I am averaging 9 mpg . . At 60-65 I can squeeze 10-10.5

Wow I wish you would have ask that question while I still had my 2012 Longhorn. I had done a little work on it i.e.. partial delete and a special tuning program. ON it towing my 38Gk a bad day was 11 mpg I seen had figured mileage of 12.3 mpg on a common day towing at 68 mph. my 2016 Longhorn is a 4x4 DRW and totally stock with all EPA garbage still intact. A good day is 11 and more commonly I see 10-10.5. I keep a log on my oil and fuel cost and figure all MPH by hand rather than trust the computer. i was a Ford man for many years. My last Ford was a F-250 4x4 and towed a 38 foot Carriage Extreme 5. Towing that i seen 13-13.5 running 73 mph. That was the sweet spot. I totally deleted it of all EPA garbage and it was a great 6.0 engine. Running empty at 70 mph it would consistently get 21mpg.

Last year from the West Coast to the rally, through Ontario and back to the West Coast I averaged 15.4 mpg (Imperial), which is about 12.8 to the US gallon. I only travel about 55, maybe 60 and coach is only about 15,500 lbs

With the 2012 SRW for a similar trip I averaged almost 17 mpg (Imperial), which is about 14 US.

Not towing, around town I get 18 mpg (Imperial) or about 15 US.

Empty I get 18-19. Towing at 64 mph(when OD kicks in) I get 11.5 - 12. running deleted DEF in tow mode.
123000 on 2013 Chevy Duramax dually.

2014 Ram 3500 4x4 Laramie Longhorn Crew Cab with 8' bed.

Open highway - No RV - 21-22 mpg

City - 17 mpg

Open highway - w/RV - 60 mph - 10-11-12 depending on terrain.

70 mph - 9 mpg

No modifications to truck. Still under warranty. If not under warranty, I might look at the Bulldog controllers. Need to do more investigation when the time comes.

It seems counterintuitive, but the best mileage I got with any RV is through the mountains, especially I-70 over the rockies which was nearly 70% of our trips. As hard as you pull uphills, the trip downhill with fuel injection means you aren't burning any fuel so it averages out, and because the speed is slower than flat interstate you do pretty well and I'm always shocked.

The worst mileage was open highway when I pushed speeds up to 75.

I get about the same MPG. Average 9-10 mpg with rolling hills and wind, running around 70. I've gotten as little as 7 mpg with a stiff wind and big hills/mountains, and as much as 11.5 or 12 mpg on flat terrain. Seems to help alot if or when I stay under 70 mph, even if its just 68 or 69.

I thought I was using alot of DEF but the dealer couldn't identify an issue. Finally I got a check engine light because the SCR and DPF went out (basically the whole exhaust system). When the dealership replaced it they reprogrammed the computer..........................didnt change my MPG's but it made a huge difference in how much DEF I used when towing.

I have a good friend that has a Ram truck also & he thinks his DEF use is excessive, has to add 2.5 gals every 1000 miles & more if towing. Mine uses about 2.5 gals in 3000-3500 miles & towing or not makes no difference.