Brian's comments about proper maintenance and things like proper tire pressure are very important.  But, the math says the most important thing is speed in most cases.

This will vary a bit with every rig and how it is geared.  A lot slower does not necessarily mean better gas mileage.  But in general - rule of thumb for most situations - when one goes much above 55 MPH the wind resistance becomes much more significant and the miles per gallon go down.  It's just math and the horse power (which means fuel burned) required to "push" the RV through the air really goes up.  (There is a formula but way to many variables to put that out.)

A head wind will do the same thing, I.e. use more fuel for the same speed.  And, BTW, a tail wind does you no good.  (Not like an airplane.  Its different.)

So, in general, once the vehicle is in top gear, whatever that is, and about 55 MPH, that is probably around the best MPG one will get verses actually getting someplace in a reasonable period of time.  Obviously this can vary depending on the gearing of the vehicle, the overall frontal area of the rig and the distance off the road of the bottom of the rig.  (Lower is actually better.)  Naturally I am mostly referring to vehicles geared to tow or properly geared motorhomes.  Not vehicles used for towing that while rated to tow a given load are not really geared for that purpose but more for solo operations.

Obviously mountain driving throws all the above out the window and other techniques come into play to save some fuel.

One other point - The use of the cruse control - except on mostly flat roads - will increase fuel use somewhat - at least as a percentage.  One can learn to "feather" the fuel and save some fuel.  Key is not allowing the cruse control to "floor it" to regain speed quickly.  Be light on the right foot.  It's a learned technique.

Good mileage and RV's are not typically used in the same sentence if you follow me.  Just a fact of RV life.

FWIW and safe travels.

 

Russ Ranger wrote:

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Another big factor for me is the physical/mental strain of driving fast.  I am much more relaxed after a day of driving "slowly" down a country road.

-- Edited by Russ Ranger on Monday 15th of January 2018 09:18:16 AM

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 In overall dollars... this might be the biggest cost savings of all. Less stress will definitely save you money on healthcare visits, not to mention spending on "feel good items" after a stressful day. Just sayin'. In turn those savings can be used for other priorities. 

Brian

I think it's my fault that I'm comparing the fuel efficiency of my car vs my RV. I guess I should stop thinking that way. Thank you guys for the information. ;)

deewelch wrote:

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I think it's my fault that I'm comparing the fuel efficiency of my car vs my RV. I guess I should stop thinking that way. Thank you guys for the information. ;)

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 I've seen studies on RV forums and RV publications showing the overall cost and impact on the environment is less when using an RV vs. Other forms of travel especially comparing fulltime RVer's to folks who still live in houses and travel.

I've always considered the "life" factor... I enjoy life a lot more when I'm out in my RV so I really don't care what the cost is.

One other thing to consider is OVERALL or TOTAL fuel use. Consider two RVs at opposite ends of the spectrum - one is a large, heavy 5'er towed by an F550 or similar, and the other is a popup towed by a smaller car. If they would travel together everywhere, obviously the smaller car towing the popup would use less fuel than the F550, not just while towing but also while sightseeing or going to Wal-Mart.

When we first started thinking about full-timing, Jo Ann was opposed to a motor home because of the very poor fuel economy. Later, we figured out that we would always have something towing something else when going from one campground to another. Yes, our Foretravel only gets around 8 mpg, but the Jeep that follows behind gets quite a bit better than that, and the next towed will do even better.

Proper maintenance is a big part of good fuel economy. Changing the air filter, fuel filter, etc. helps. Not idling any more than necessary helps. Proper tire inflation helps. Keeping weight down helps. No one item will make a big difference, but all of them together will help.

As Larry mentioned above, parking the RV and exploring the area in a more fuel-efficient vehicle helps. Parking the RV for a week or two reduces the fuel the RV uses. We try to follow that practice, but there are times when we need to move long distances in a short period of time. Those months see greater fuel use. Frequently we are parked for a month at a time, so diesel purchases are minimal (fill the tank when we arrive).

yandel wrote:

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 Great tips there. Cruising at right speed and conserving the momentum as much as possible really make a good difference. Here at the shop, we also observe the proper tires and tire pressure. One experiment, we installed lighter ultra wheels and AT tires on buddy's truck last year coming from steelies and stock tires, he mentioned gaining about 20% fuel mileage difference after 2 months.

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 I include proper tire pressure in the "well maintained" category, and I agree, there are other steps that can be taken such as tire/wheel changes. My goal though, was to point out factors that can significantly improve fuel economy at no cost.

We went to the Canadian Maritimes the year when diesel was over $6/gallon - Dave refused to even look at the dial as it whirled by. You just have to plan accordingly.

I agree with Dutch - the amount of lead in the right foot is probably the greatest single factor in fuel mileage. Another good thing to do is to go through and see if you really need everything you are carrying. For fulltimers it is very easy to have that weight gradually creep up as you find another nook or cranny just crying out to have something else squeezed in.

Barbaraok wrote:

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We went to the Canadian Maritimes the year when diesel was over $6/gallon - Dave refused to even look at the dial as it whirled by. You just have to plan accordingly.

I agree with Dutch - the amount of lead in the right foot is probably the greatest single factor in fuel mileage. Another good thing to do is to go through and see if you really need everything you are carrying. For fulltimers it is very easy to have that weight gradually creep up as you find another nook or cranny just crying out to have something else squeezed in.

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 Isn't cruise control a wonderful thing?

Danny and Cheryl wrote:

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deewelch wrote:

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I think it's my fault that I'm comparing the fuel efficiency of my car vs my RV. I guess I should stop thinking that way. Thank you guys for the information. ;)

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 I was that way for us as Each of us have a 2012 Prius that avg 49/50 mpg.  it is hard to swallow the 10 mpg that my RAM 3500 Diesel gets towing my 5er

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 My thinking is to not consider towing MPG as you would for commuting. It is after all part and parcel of your essential housing expense. Look at it more like a utility bill. You can reduce such expenses by simply not relocating so often or... if that is your thing, then it's simply a cost to keep a roof over your head. (granted, your "roof" keeps moving around.)

FWIW, Brian

-- Edited by BiggarView on Monday 12th of March 2018 11:40:18 AM

Something as simple as a clean air filter can improve your fuel economy up to 10 percent.
Checking and adjusting your tire pressure to the proper pressure can increase fuel economy by three percent, not to mention preventing premature tire wear and failures or blowouts caused by over or under-inflated tires. Tires can look normal when they are seriously under-inflated. Use a quality air pressure guage and check your tires when they’re cold, before traveling more than one mile.
Excessive idling wastes fuel. If you’re going to be sitting still for more than a couple of minutes shut the engine off.
Using overdrive whenever you can saves fuel by decreasing the engines speed.
Using the cruise control whenever possible saves fuel because it keeps the vehicle at a constant speed rather than variable speeds. But keep in mind the over 60 mph rule applies here too.

arcaguy wrote:

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I can't add much to the above except for a cute little thing I heard a few years ago: "All of those in favor of better gas mileage, raise your right foot!" Keep the shiny side up.

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 For me that might improve my overall mpg from about 7 to 7.5 or even 8 mpg,  It does not help at all in the mountains or in city driving.  

Edit: I should clarify.  In the flat, flat Midwest, where I can drive 65 mph I get over 8 mpg.  In California and Oregon, where I can only drive 55 mph due to towing, I mostly get 7 to 7.5 mpg due to mountains and traffic.  In my car my worst mpg is in city driving.

-- Edited by bjoyce on Sunday 29th of April 2018 09:49:32 AM

Interesting that we seem to do better with mpg when in CA and OR than Bill - - right around 8.5. Always figure what ever we lose going up a mountain pass we gain coming down the other side. I don't look at each fill up, but rather over a period of time. With over 150K miles, she stays between 8.5 and 8.75 year after year.

Wait until Bill and Diane unload their rig next fall into their park model. Come spring the coach will act like a 'new spring chicken' when all of the winter stuff is left behind.