Why does my MPG suck so bad?

[mia389]

I have about 3,000 miles on my Cummins 2500 now. I am getting around 14-15mpg normal driving and when I tow my 9,000 TT I getting 8.5mpg at 75mph. This shocked me! I thought I would get better mileage than this.
I took a 1600 mile trip up north and back and was filling up 2 hours of towing. Is this what you guys are seeing as well?

 

[skiploder]

5k miles on truck. Getting around mid 18 mpg mixed.

Trip from Kanab to Ft. Collins and back. 20 mpg.

 

[RPS1030]

Pretty much. Between the 15ish average and sucking down the DEF, I was pretty ticked off at the truck until 15k. From 15-20k miles, the numbers got a lot better.

Most tanks are 17-18now. Towing Jeeps is about 10-12. Almost all the highway is at 75-80 mph in both cases.

 

[Surf2snow1]

Maybe they accidentally gave you the 6.4L hemi.

 

[Squatch]

Maybe they accidentally gave you the 6.4L hemi.

Yeah, those are my numbers on my 6.4

 

[jetrinka]

Not bad for a vehicle that weighs as much as it does and makes as much power as it does

 

[Greenhills]

Empty - mileage is 18-19 MPG. Hook any trailer to it, gone out the window. 1200 lbs or 10,000 lbs, doesn't seem to make a difference lol.

 

[Sir Snacksalot]

I’m a conservative driver and normally Stay 60-65 mph since the speed limit here is 60.. I see 21-22 on the highway empty and ~12 towing my 7500 lb TT


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[Brutal_HO]

8.5mpg at 75mph

I think you answered your own question.

Pulling 16K, I'm lucky to get 7.5MPG running 70MPH with my HO. It will get better as the engine "finishes" but the EPA is to blame for much of this.

 

[H3LZSN1P3R]

Around 60-65 will net you the best millage i get about 19-21mpg empty and the loaded is relative to the trailer weight i have seen 14-15 with my dumptrailer weighing in at 7k and 9-10mpg with my 10k 5th wheel….it does get better with time i have about 20k miles on the truck it has gotten better over time and should get even better when the warranty expires and i go full delete on it

 

[Moose074]

I was worried as well, my 2018 Ram was averaging 14-16 mt depending on speed and wind. When towing I was getting 8 on average and an occasional tail wind or no wind I got 10 mpg tank. My new 2021 I was averaging 13-14 per tank I was very worried about towing numbers. Just took a 5k trip with trailer worst tank towing very strong headwind most of day 7.8 averaged 9 towing best was 12 blew my mind trip meter said 12.1 hand calculations was 12 ( 11.93) . So mpg towing was better gonna take 6 hour drive so be nice to see if mpg goes up since I towed 15k trailer thru the western mountain ranges and I pushed it hard trying to break it in.


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[Rockcrawlindude]

you’re driving too fast.

 

[Razzman]

Ironic I saw this thread as I too have suddenly experienced mileage drop. I always average around 14.5 mpg pulling our 7K trailer, nothing for this truck. Suddenly last week I'm getting 9-10 mpg towing on the flats, and I tow at 60-65 mph. Also noted is when I fill up the EVIC always shows around 435 miles to empty (yeah I know these are not accurate) but when I filled up last week it showed only 240. Something is going on for sure. I'm going to fill up again in a few days and see what it says.

 

[Jacob]

I normally get about 17mpg.
10 to 11 towing a 5th wheel.
12mpg towing cargo/travel trailer

 

[Greenhills]

Was thinking about this thread while cruising down the highway at 120-125 Kmph (in Canada). No **** your mileage is bad, why are you towing so fast?

 

[duallyben]

Best mpg I find is when going between 62-65 mph. I towed daily same trailer, same path with the weights changing, but a cargo trailer so the resistance stayed the same.
Also keep in mind most trailer tires say to keep it under 70 mph.

 

[Southernspeed]

I have about 3,000 miles on my Cummins 2500 now. I am getting around 14-15mpg normal driving and when I tow my 9,000 TT I getting 8.5mpg at 75mph. This shocked me! I thought I would get better mileage than this.
I took a 1600 mile trip up north and back and was filling up 2 hours of towing. Is this what you guys are seeing as well?

I'm getting those numbers in my '21 3500 but towing heavier and slower (60-65) Gentle driving with no trailer is pretty disappointing though. Only got a couple of thousand miles on it so hopefully it'll improve.

 

[Whitewolf]

A deleted '14 I recently traded in would get 21.5 on a 1000 mi trip to Missouri averaging 73 mph between the states. I would get 27 doing 58 mph on two lane roads. Following whatever the speed the big trucks were going while towing, I would average 12 mpg. All hand calculated and with 3.42 rear gears.

The '21 I traded for will keep all the mandated stuff and has 3.73 rear gears. I already know it's not going to get the same milage as the '14. I'll know more at the end of the month when we pull our 5r to Colorado.

 

[Brutal_HO]

Best mpg I find is when going between 62-65 mph. I towed daily same trailer, same path with the weights changing, but a cargo trailer so the resistance stayed the same.
Also keep in mind most trailer tires say to keep it under 70 mph.

True and salient point for most traditional ST rated tires (technically ST is rated to 65MPH) but many modern tires, including the Goodyear Endurance I run on everything, are rated higher. 87MPH for the GY's. Not that I tow that fast...

 

[dragon_ram]

How odd. I got 11-ish towing a 9k lbs TT from AZ to Glacier NP and back 9 months ago (1300 miles). However just last week I got 8 towing the same trailer 690 miles. WTF? 65 mph…