Although gas prices are unpredictable, smart driving habits can get you more for your money.

When catastrophic weather in the Gulf of Mexico crippled four refineries last summer, fuel prices in the U.S. soared from $2.39 a gallon to $3 – an increase of 25 percent over the course of the day. That was before the wind and rain.

The refineries serve the East Coast states of the U.S., not Canada. The U.S. obtains two thirds of its crude oil from Canada, more than it gets from the Arabian Emirates. But still, in some areas of Eastern Canada, prices shot from $.90 per litre to more than $1, marking a whopping increase of 48 percent!

Price appears to be driven up by speculators gambling on the futures market, hoping that gasoline supplies will be short. In the meantime, fuel suppliers have reaped a bonanza that could potentially repair all of these refineries with the extra income they’ve received in a very short period of time.

On our recent trip through the American Appalachian and East Coast areas, we heard from car owners about how awful it was that fuel prices were rising. None of the RVers we talked to were upset. Most don’t travel every day. Staying an extra day at each campground can double your fuel economy.

The next greatest improvement in fuel economy could be the speed we drive. Driving faster pushes more air ahead of the RV, which creates more resistance to forward movement.

The most economical speed to use when driving a large rig is 55 miles per hour (mph). For every five miles an hour you go faster, you’ll lose one mile per gallon (mpg). If you get 10 mpg at 55 mph, then at 75 mph, expect to get six mpg. At a price of 98 cents per litre, it costs $44.50 to drive 100 miles at 55 mph. If you like to drive faster at 75 mph, you’ll pay $75.16 to drive the same distance. Slow down and save money.

Turbulence can be a problem while driving. RVs that have a vertical rear wall tend to create a vacuum behind the vehicle. We often see the rear of RVs covered with dirt. Towing a car behind a motorhome often forces air turbulence to go further back, which breaks the vacuum. A trailer towed by a truck often has turbulence created between the tow vehicle and the trailer because of air tumbling around between the two vehicles.

Trucks towing fifth wheel trailers don’t suffer from this turbulence since the trailer overlaps the truck bed. In tests we’ve done with pickups, when the tailgate is down it creates more vacuum behind the cab, resulting in lower fuel economy. With the tailgate up, the air in the bed forms a bubble that reduces the vacuum effect of air flowing past the cab, resulting in less strain on hinges and sidewalls. If manufacturers believed that driving with the tailgate down was better, they would sell trucks without them.

Tire pressure also affects fuel economy. For every pound tires are under-inflated, fuel efficiency drops by two percent due to increased rolling resistance. If you have six tires on your RV, and they’re under-inflated by five pounds, you’re losing 12 percent of your fuel economy. Keeping your tires properly inflated could save you the cost of the fuel price increase. If the tires are low on air, the engine has to push harder to move the RV ahead.

Most RVs don’t benefit from burning Hi Test gasoline. Regular is just fine. The Hi Test (higher octane) gas simply burns later in the combustion stroke than regular gas. One thing that will reduce your fuel economy by one-half mpg is your cab air-conditioning system. Use your generator to operate the roof air-conditioner. You can run the generator for an hour on a half-gallon of fuel.

I did a cost comparison for a reader who asked about the difference in purchasing a diesel- or gas-powered motorhome. He had the option of purchasing the same floorplan and size of motorhome in either a gas or diesel chassis from the same company. The difference up front to purchase the diesel was $50,000. He told me he would probably drive about 5,000 miles a year during his trips.

Using the costs two years ago, I calculated that he would have to keep the diesel motorhome for 197 years to save the upfront cost of the diesel with the lower fuel costs and better fuel mileage. Buy a diesel chassis because you want a diesel, not to save money.

Maintenance is important to keep your engine performing on all cylinders. A clean air filter allows more air in to burn the fuel, and clean injectors and carburetors control the flow of fuel into the combustion chamber. Use the recommended oil in your engine. Some drivers have found an improvement by using synthetic oils. If the hills are moderate, it’s okay to use your cruise control on the way up. If hills are steep, the cruise will dump more fuel into the engine while trying to maintain your speed.

If you’re driving up a hill and your RV doesn’t gain speed when you press on the accelerator, your engine is heating up as the extra fuel is simply being burned in the exhaust system. Feather the accelerator until you notice a slight change in the speed. To prevent the engine from lugging, use a lower gear when you’re climbing hills.

Avoid driving in stop-and-go traffic. If you arrive during a city rush hour, find a shopping center and have dinner. Ideally, miss the rush by arriving at your campground by 4 p.m. so you can relax. (Page Top)