By Russ and Tiña De Maris
A gent new to RVing was in a bit of a quandary: Looking for good economy he bought himself “hybrid” travel trailer; the rig provides a hard sided RV with “pop out” beds to increase living space while still keeping the “towed size” down. At 4,000 pounds he felt his new, lightweight rig would tow with good economy.
Hitching up to his old reliable SUV, which when traveling “solo” gave him over 16 miles per gallon, he was shocked to find his towing mileage jumped off a cliff to about 10 miles per gallon. Was he doing something wrong? Were his trailer brakes sticking? Just what is a reasonable expectation for fuel economy when towing a trailer?
When fuel prices are high it’s a question on many RVers minds. The answer may not be the one you want to hear, but there is some hope.
First off, plenty of seasoned RVers will say, “What’s the beef? Seeing double-digit fuel economy is about as likely as sighting a Sasquatch!” If you’re towing with a gasoline engine tow vehicle, you can expect a less-than-ten figure as the order of the day. “It’s the price of doing business,” is a common thought. “Just don’t look at the fuel pump when you’re RVing,” say many. “If you worry about how much it’s costing you, you won’t enjoy the lifestyle,” say others.
True, towing (and motorhoming) is not a proposition to be taken lightly. Still, you can do some things to improve your economy. Diesel owners will tell you they have much better fuel economy than an equivalent gas engine rig, and from our own experience, it’s true. Our 7.3 liter diesel pulling a 24 foot, 5,000 pound trailer generally “sees” around 12 or better miles to the gallon. Granted, we pay more for diesel than gas. Still, using today’s gas versus diesel prices we figure we’re ahead with our 38% better than the average gasser fuel economy, even taking into account we’re paying 15% more for diesel than gas.
Regardless of your fuel of choice, there are things to be done that can help. First, the consensus among RVers is that weight, per se, is not the enemy. Aerodynamic drag is the killer of fuel economy. The more “face to the wind” you have, meaning the larger the front of your trailer, the more fuel you’ll burn. Mind you, much of your trailer front will be “hidden” behind your tow vehicle. But if you crave a “tall” rig, one that sticks up above your tow vehicle, you’ll pay for it at the pump.
Some of the greatest drag reduction is found under your foot. Yes, it pays to have both feet in the truck when you pull away from the curb, but getting off the gas pedal will work wonders. Here’s a little law of physics to go by: Double the drag, quadruple the force required. Translated: Go twice as fast, the amount of energy required to move your trailer goes up four times. Slow it down! If you hate paying dollars at the pump and drive at 65, try driving at 55 for your next tank or two and compare the changes in fuel economy.
Keeping the drag forces down not only means keeping wind away from your front end, it also means keeping wind in your tires. A single tire underinflated by 10% costs you 3.3% in fuel economy. For the sake of argument let’s say all your tires are inflated 10% less than they should be. Four tires on the tow rig, four tires on the trailer, eight tires at 3% fuel economy loss each–24% loss of what might have been. If you’re getting 10 miles to the gallon with low tires, wouldn’t you rather go over 12 miles to the gallon by bending over and pumping those tires up?