Fuel mileage pulling TT

Air resistance increases by the square of the speed.  Drop your speed by 10% (from 68 to 62 MPH, for example) and you'll decrease the wind resistance by almost 25%.  Decrease your speed 20% (from 68 to 55 MPH) and you'll lower the wind resistance by more than 50%.

Since wind resistance is the major consumer of engine power at highway speeds, you'll boost your gas mileage by close to these amounts.

Not a tt but with a 1 ton single rear wheel duramax, I could 13 pulling an enclosed gooseneck 4 horse trailer with extended living quarters fully loaded but I always drove extra cautiously because of the horses.

I just got back from a 2,500 mile trip, from Illinois, to Sturgis, SD to Colorado Springs and back to Illinois.  2008 Chevy Duramax pulling 35' 5th wheel toy hauler, fully loaded right at 20,000lbs total weight, truck and camper.  Tried to drive about 65, and I was not using cruise control.  I averaged about 9.5 mpg for the trip.  Had good weather just about the entire trip and never had any substantial head wind or tail wind.

Ok, now that I've returned from my trip, I can post the actual results:

On the way to Dallas, I used the Tow/Haul option and set the cruise control @ 68mph.  On the way there, I was quite disappointed at only 9.5 mpg, but with a slight head wind.

On the way back home, I set the cruise control @ 65mph.  I was able to achieve 11 mpg.

As someone mentioned, the wind resistance is the killer as I can see.  I reduced my speed and was able to lower the wind resistance and get better mpg's.

I'm so used to pulling flatbed trailers that I didn't think it was going to be that bad.  A few days before, I drove to Arkansas to pick up a new vehicle that I purchased for my wife (Toyota Highlander Hybrid).  With cruise set at 75mph, I was able to get 12-13 mpg's.

On my trip to Dallas, I looked for people Northbound, but mostly saw people Southbound as they were going back home from evacuating from the TS Lee.  Going to Dallas, I only met 3 RV Trailers.  The 1st was right outside of Lafayette where the speed increased on the interstate from 50 mph to 70 mph.  I met a guy here and I quickly left him traveling at 68 mph.  The next guy I met was pulling a 5er near Shreveport as I got onto I-20.  I had cruise set at 68 and I passed him as it seems he was driving closer to 64-65 mph.  The next guy I met, I nearly blew him off of the road.  I guess he was traveling somewhere around 55mph with a 1/2 ton pulling a TT.

I think the next trip I take, I'll try the speed out around 63 mph and see what that yields.

I appreciate all of the info from everyone.  The trip was great and really paid off. 

My rig weights in at about 18,600lb and I average 10-12 depending on wind and hills. Here  in Southern California I stay at 60mph/1900rpm so as not to get a ticket plus that seems like that is where my D/A likes to run. I am in no hurry when I am on the road, to much to see and safety come first for my family and I.

Well I got back from a wonderful trip up to Kirkham Hotspring, Idaho crossing the scales at 16,080# combined weight I pulled 14.13 MPG hand calculated... This included climbing over 7% grades and windy back country roads. I'm happy...  ;D

I just got back from Florida and I got between 9 - 10.5 MPG at 62 / 65 MPH no wind no rain! I now have 9000 miles on my 2011 Dodge 2500 Diesel. I am not impressed with the MPG.

I pull our Montana 40 ft Model 3750fl, 5th Wheel, with any of our Dodge D3500 Diesel trucks. Just a month or so ago, with one of our Dodge trucks,  we traveled to the Good Sam Rally in Oregon from Colorado, then went to the Rogue River area, Portland, back through Central Idaho and Wyoming, with local traveling at the areas where we camped. The trip lasted slighly over 2 weeks. By actual measure of miles and gallons of Diesel we averaged 16.3 MPG for the whole trip.

My experience pulling our RV and also our ranch trailers shows that this typical for our trucks.

I am sure our experience would vary with different trucks, etc.

I have an 05 GMC 4x4 with a Duramax.  I pull a 27 ft Hornet that weighs arround 8000 pounds loaded up and I get around 14 mpg.

Well, if you drop that 75 mph down to 60-65, you get better mileage and have better stopping ability.

Lead_Sled said:

I'm able to get 18.5 mpg @ 75 mph.  Hand calculated and not going by the onboard computer.

Thanks for any input,

Click to expand...

What did the on board computer compute?

3500 GMC Sierra Diesel (single) pulling 13-14K.  Brand new (only up to 3k).  Only have calculation done from one 60 mile tow.

18 highway truck alone
13 overall truck alone
10-11 towing (included a lot of bumper-to-bumper highway traffic and about 6 miles of local driving)

Kind of hard to believe (for me anyway, first time diesel owner) but our F350 just keeps getting better while towing, currently have 12k on the 2011.  Anyway, we are currently getting like 18mpg without towing and just shy of 12mpg with towing our SRX.  I have been towing pretty heavy, golf cart in the bay, generators in the truck bed and usually full of water.  Depending on the roughness of the road, we usually do about 65mph, interstate 95 is getting pretty beat-up and I hate the bridge bouncing... but Rt 81 we have been comfortable at the speed limit of 70 without problem.

10,000  pound 5th wheel, 1996 dodge in the sig, and right at a 13 average for about 6000 miles so far.
Saw a high of 15 or so, low of 12. Speeds from 55 to 70.

With my '06 2500 Chevy pulling a 35' Montana, I get 10.3mpg.  I think pulling at 63 to 65 the engine doesn't seem to work as hard.  I only
have 71,000 on it and may get better mileage with age.  I don't think pulling faster is safe and I sure gas mileage would be worse due to wind.

If anyone is worried about gas mileage then I suggest buying a programmer as, they do work and will add miles/gal,  Of course, this is greatly influenced by the way you drive.  I have a 2004.5 Dodge 4x4 and bought a Smarty Jr.  I am getting an additional 3-5 mpg city, 4-5 mpg on the road, and 2-3 mpg towing my 5'er.  I paid $485 for the programmer and figure I will recoup that expense after 20-25 tank fill ups.  In my book that is a pretty good pay back. 

I have a bumper pull 23 ft toy hauler and when loaded with our Polaris RZR, water, fuel and ready to go it weighs 8700 lbs. I usually set my cruise on 65 on interstates and get 11 mpg. When empty it doesn't do that well at 14 mpg but I mainly only tow with it so the empty milage doesn't concern me. This is a bit better than my old 2001 2500 that got a consistant 10 with the same load down the same road.

Our mileage varies a bunch depending on conditions.  I've gotten 9.0 with a headwind and 12.0 with a tail wind while towing.  The most meaningful  calculation is made by averaging many trips.  A one time calculation is a start, but isn't worth a lot.

Here is a picture of my fuel logs for my 02 Dodge Cummins pickup... This is from 20K miles to current all hand calculated mileage. No there is no numbers below 14 MPG in the log... This fuel log covers both towing utility trailers, the Jayco, also running empty...

http://i56.tinypic.com/2ueh9pd.jpg

I forgot to say on my 2011 Dodge Diesel I do not have to purchase the fluid to clean my catalytic converter. I saw a sign when filling up tonight 20 bucks for 2 1/2 gallons.