realistic MPG expectations

[danimal53]

after some searching, I'm wondering what kind of mileage people are getting when towing. I know the frontal area of the trailer is a big factor, as far as wind resistance, even more so than weight. What have others experiences been with mileage? What kind of mileage does your TV get when not towing, and what do you get when towing? I have a jeep liberty, towing a coachmen clipper 17bh with 3700lb max. We'll be going on a long trip next month, so I'll have a solid number for my average MPG then.

[legolas]

2008 Silverado 2500HD (gas) pulling 5600lb TT weighing in at 6200 loaded out, consistently get between 9 and 10 mpg

[Community Alumni]

dodge guy wrote:
My gas mileage with the wind deflector would disagree with you! I bought one 2 years ago and my towing mileage increased by approx. .8mpg. so my $75 craiglist investment paid for itself on our trip to Myrtle Beach. My Excursion tows very differently with it. no more does it downshift at the slightest headwind or hill. and with my scanner the throttle opening % decreased by about 12%. so yes they do work, but as was stated they need top be back near the TT. On my X the wing is at the very rear and it does what it is supposed to do. I believe on a Pick Up truck with a TT it would not be very helpful due to the distance between the trailer and cab.

Maybe you have more of a perfect setup. I was interested in them years back and did a ton of research. From reading the posts of many who've purchased them before, most say that it's not worth it. The vehicle height differential, angle of the deflector, width of the deflector, and the gap between the deflector and the trailer all have to be setup correctly in order to see any real gains. Often times the airflow falls off the trailing edge of the deflector and gets sucked into the low pressure trailer gap negating gains.

[2012Coleman]

colliehauler wrote:

SprinklerMan wrote:

2012Coleman wrote:
Why even worry about MPG? It is what it is. Forget about it and just enjoy camping.

Exactly , I dont even look at the pump when i fill up , it uses what it uses .

So you know how far a tank of gas will take you between fill ups.

I don't need to know how far a tank of gas can take me. When it falls to a 1/4 tank of gas, I start looking for a good place to pull into.

[gcloss]

SprinklerMan wrote:

2012Coleman wrote:
Why even worry about MPG? It is what it is. Forget about it and just enjoy camping.

Exactly , I dont even look at the pump when i fill up , it uses what it uses .

I agree 100% ..... I just drove 845 miles in the last 2 days through the Shenandoah Valley. Flying J and Pilot are my new best stops for me getting 9mpg.

If I'm really concerned about mpgs, then I shouldn't own a TT.

[eichacsj]

SprinklerMan wrote:

2012Coleman wrote:
Why even worry about MPG? It is what it is. Forget about it and just enjoy camping.

Exactly , I dont even look at the pump when i fill up , it uses what it uses .

X3, my feelings exactly.

[gmw_photos]

Slowmover wrote:
Were the square box versus aero fuel burn comparisons based on travel speed, climate, terrain and use of cruise control? Was the comparable solo figure given? ....snip.....

I don't know that you were specifically addressing me from my earlier post, but I will make this observation: I have a square box trailer ( funfinder 19' ) and a two horse bumper pull trailer. The horse trailer just coincidentally is about the same length and width as the funfinder. The horse trailer is lower to the ground, has a rounded front, rounded top edge at the front, and rounded wall/ceiling front to back. Admittably it's square and flat at the back. It weighs very close to the same as the funfinder when I have one horse in it.

I pull both these trailers with the same truck. I get essentially the same fuel economy with either trailer, pulling over the same roads. Either one is within one to one and half mpg of the other, mostly depending on how fast I run and what the wind conditions are for the day. These are pencil and paper figures over many tanks of fuel. I've pulled the camper close to 25,000 miles and the horse trailer several thousand miles in all different weather conditions. So at least for me, I just don't see a difference to speak of.

Again I go back to the idea of of, "if a user has worry over a few more hundreds of dollars spent on fuel, then RV'ing may not be for them".
This is not a cheap hobby. If a person wants to travel cheap, buy an economy car and a $100 tent at walmart. Not trying sound snippy, but it's just this whole RV thing is not an inexpensive way to see the country.

[Bumpyroad]

Slowmover wrote:
It's the lack of raduised edges all around. A 30% reduction in aero drag results per NASA. Ground clearance too high is the other. Why big truck trailers now sport skirting.

A 50% reduction in FE is worth investigation. That's terrible.

I saw a semi with the skirting under the trailer which had written on it that said it was to improve stability and safety (IIRC) but definitely did not say anything about economy.
bumpy

[RavensFan24]

We get about 8-9 mpg while towing. Always underestimate what you think you'll get though for safety and sanity's sake.

[Slowmover]

Were the square box versus aero fuel burn comparisons based on travel speed, climate, terrain and use of cruise control? Was the comparable solo figure given?

Anyone here AVERAGING 14-16 mpg pulling 28-35' trailers? Have found over a dozen towing all aluminum aero trailers in the South Central U.S. using early HPCR Dodge turbo-diesels towing 58-65 mph. Long term numbers not a few tanks. This is my experience, CPM in sig per current diesel prices.

And is anyone here in the twenties with a 24' or shorter? Again, dig deeper for a survey. This trailer type is towed by everything from a TD VW Jetta to high BMW and Mercedes.

Or about 26-solo and 20-mpg pulling a 6000-lb GVWR 26' TT with an Eco diesel? That might drop with more miles, but its an initial average.

But these are absolute numbers. It's the spread from solo to towing expressed as a percentage that counts.

Airstream says about a 20% savings in HP demand. I find that a thirty percent fuel burn penalty is common, with some worse. Usually there are factors at play (such as high speeds like 70+ mph and/or lack of CC use; or almost purely mountainous terrain) which are explanatory. Then it gets closer to forty percent.

Look to comparable solo and towing numbers under otherwise same conditions (above). It's much easier to maintain a lower fuel penalty towing an aero trailer. And for a motivated driver to keep the solo/towing spread UNDER thirty percent.

And some just don't care. They've no more real idea of average mph than they do of combined rig weight, same as here. No set of default numbers for the WDH settings or of tracking fuel burn.

[Jayco254]

It don't matter if it's the Expedition 4X4 5.4 eng. 6spd. trans. and 3.7 gears or the Ram 4X4 5.7 (hemi) 5spd. trans. and 3.9 gears I still get between 9 & 11 mpg. depending on wind and hills, towing a 6100lb. trailer at 55 too 62 mph.

[gmw_photos]

Slowmover wrote:
It's the lack of raduised edges all around. A 30% reduction in aero drag results per NASA. Ground clearance too high is the other. Why big truck trailers now sport skirting.

A 50% reduction in FE is worth investigation. That's terrible.

And yet when we go over to the Airstream travel trailer forum we see the members there reporting pretty much the same fuel economy as the guys here that are pulling square boxes. So the rounded ends and walls of the Airstream seems to do little in the real world to help gas mileage.
Bottom line is is you have to worry over a few mpg one way or the other, then RV'ing probably is not something you want to do.

[Slowmover]

It's the lack of raduised edges all around. A 30% reduction in aero drag results per NASA. Ground clearance too high is the other. Why big truck trailers now sport skirting.

A 50% reduction in FE is worth investigation. That's terrible.

[atreis]

Most people, regardless of tow vehicle, get between 9 and 11 mpg if towing with a gasoline engine. The difference seems to have more to do with speed than anything else. (I get 11 mpg while towing - and tow at 60 mph. I get 23 mpg not towing.) No matter what you tow with, you're still towing a very non-aerodynamic wall down the highway. If it has a V-shaped front, it's still very much not aerodynamic - the flat back gets you too.

[Mr_Beebo]

8-9.5 towing either our camper or my 20' cargo trailer for work. On long trips, like others, there is a 5 gallon gas can in the back. I don't mind stopping every 200 miles. That's about 3+ hours of driving and everyone needs a break anyway by that time.

[jfkmk]

12-13 mpg with a 6 cyl GMC a Envoy towing a 3500# TT. It gets around 20 on the highway not towing.