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mlbond · 06-23-2014, 10:54 AM

I am about to purchase a new 2015 GMC Denali 1-ton Dually (Diesel) for pulling my 8500lb TT and for the travel comfort of my family. Another reason for this purchase is for the future consideration of trading up to a larger 5th wheel. Does anyone have this truck and what kind of gas mileage do you get while towing? What size TT?

drewtk · 06-23-2014, 03:37 PM

I think you can expect around 10 mpg on average; obviously less in hilly areas or headwinds. I have a 2013 F250 diesel and tow an 8,500 pound TT (loaded weight), and that's what I get at 65 mph. It'll actually do 12 mpg on level ground with no wind, but that's a rare occurrence.

mlbond · 06-23-2014, 07:29 PM

Thanks DREWTK

tuffr2 · 06-23-2014, 07:40 PM

From my experience towing in various conditions with various trucks.

Expect 11 mpg with a stiff tailwind. Expect 9.5 into the wind.
Expect 10 to 10.5 w/o much wind.

chaps2018 · 06-23-2014, 09:10 PM

X2 on both replies. Matches my experience traveling across the US

Texastbird · 06-24-2014, 11:12 PM

I have managed as much as 13mpg pulling our 2410 Komfort in perfect conditions with my 3/4 ton Denali LML (2012). Usually it turns out to be 10 or 11, though, with wind, mountains and driving in traffic. This is a short and tall trailer that has a lot of drag. Anything over about 65mph and the mileage starts heading downhill. But ST tires are only rated for 65mph, aren't they, so I keep it around 60 or maybe 63 max.

fvstringpicker · 06-25-2014, 06:47 PM

I get between 10-12 MPG in my 2007 GMC "stock" LBZ towing 9,000+ TT. (most in hilly country or Appalachian mountains. Every Duramax owner I've talk to seem to get about the same regardless of the year.
My only exception was I got 14 MPG towing a 12k lb load of metal on a flatbed trailer (measured over about 80 miles)

defekticon · 06-26-2014, 02:22 PM

Quote:

Originally Posted by Texastbird

I have managed as much as 13mpg pulling our 2410 Komfort in perfect conditions with my 3/4 ton Denali LML (2012). Usually it turns out to be 10 or 11, though, with wind, mountains and driving in traffic. This is a short and tall trailer that has a lot of drag. Anything over about 65mph and the mileage starts heading downhill. But ST tires are only rated for 65mph, aren't they, so I keep it around 60 or maybe 63 max.

See that's smart. I Roll at 65 MAX speed, but I see guys with dually trucks pulling 3 axle 5ers at 75-80mph down I95 in memorial day traffic. Nuts!!

Texastbird · 06-26-2014, 03:20 PM

Same thing on I45. Makes me feel like a turtle. It seems that some people think the laws of physics don't apply to them.

FamFun4 u · 06-27-2014, 08:43 PM

I have a 94 3500 extended cab LB DRW with the 6.5 TD. Tow a 38 ft TT weighing about 9800 loaded and I'm getting 13-14 running 60 at about 2500 rpm

raytwntrvlr · 06-28-2014, 06:14 AM

I have a 2013 3/4 RAM diesel that averages about 11 or 12 mpg towing our 26' 5000 lb Shadow Cruiser. I try to keep the speed under 65. This is actual hand calc mileage not the optimistic numbers displayed by the truck's computer which usually is 2 or 3 mpgs higher. According to what I am seeing from others, in this thread and others, weight does not appear to be the biggest factor in the mpgs you will get. Shape of the trailer matters along with how you drive and in my experience for sure ... HEAD WINDS.
BTW... that sounds like an excellent rig for towing your TT. Have fun and be safe out there.