Is there anything I can do to improve my gas mileage? —Randy, 2009 Winnie Outlook
There are several things you can do to improve gas mileage when pulling your Winnebago trailer down the road. Proper maintenance, tire pressure, and weight are the first things I would look at.
Proper maintenance will improve gas mileage
Since you have an Outlook and stated “gas” mileage I assume you are towing with a light-duty truck? Make sure all engine filters have been changed to specifications and fluids are up to date, as well. Most trucks today have sealed bearings in a complete hub and cannot be lubricated; however, your trailer bearings typically can be. Make sure you do annual maintenance on the trailer bearings and brakes. Most axle manufacturers recommend repacking and inspecting the bearings once a year or every 15,000 miles.
I ran a company for the past ten years that had three trucks and trailers on the road towing more than 100,000 miles each. My drivers used an infrared laser thermometer to record temperatures of the hub, brake drum, and tire every time they stopped for fuel. Extremely hot temperatures were an indicator of bearings getting dry or brakes set too high, which could cause a failure. But we also noticed it affected fuel economy, as well, due to the resistance.
How tire pressure affects gas mileage
According to the RV Safety & Education Foundation (RVSEF), more than 50 percent of RVs they have weighed have underinflated tires. Their weighing teams have been conducting individual wheel position weighing at rallies, dealerships, and special events for more than 30 years. Underinflated tires not only cause premature tread wear and the potential for blown tires, but the resistance will also affect fuel economy.
Proper tire inflation on your trailer tires can be found on the sidewall of the tire. For your truck, typically the recommended pressure is on the data plate of the truck. The tire pressure on the sidewall of the tire is for maximum pressure at maximum weight. Typically you will not have the back end of your truck filled with that much weight. The new tires on my 2016 Silverado 1500 show 51 psi.
The tire sticker inside the door shows a different psi.
When pulling a trailer, I typically go to 40 psi, which seems to give me the best tread on the road.
Your trailer has a Gross Vehicle Weight Rating (GVWR), which is the maximum your rig can be loaded with everything including cargo, water, and LP. The lighter the load, the better gas mileage you will get. Make sure you get your rig weighed and find ways to lighten it by not carrying full water, which weighs 8.6 lbs. per gallon.
Also, make sure your tow vehicle matches the weight of your trailer. One year we purchased an F-250 with the Triton V10 that supposedly had a towing capacity of 11,000 lbs. Our trailers weighed about 8,000 lbs. We got 6 mpg with that truck and could barely get over a 6 percent grade. We got rid of that right away and went to diesel.
Driving characteristics that affect gas mileage
How and when you drive can also affect fuel economy. The faster you drive, the fewer mpg you will get. The more traffic you find means the more fluctuation of speeds you will encounter and affect fuel economy as well. If possible, plan your trips for times with less traffic or reroute to avoid high traffic such as big city driving or mountains. Use a bypass option, if available.
Also, try to avoid wind, if possible. A strong headwind can cut fuel economy in half. I know several RVers that just pull over when they hit a strong headwind and relax for a while until it dies down. After all, they are not in a hurry as they are “recreating.” Plus, they don’t like fighting a headwind, either.
My truck is designed for “FlexFuel” so I can choose to run Premium, Super Unleaded, or E85. I typically run Super Unleaded at 87 Octane. I tried Premium during one of my trips and did not see any difference in fuel economy. However, when Super Unleaded hit the $4.79 mark, one of our local fuel stations had E85 for $2.99, so I tried a couple of tanks and my fuel economy dropped by 4-5 mpg! Saving $1.80 per gallon did still make financial sense, but now that Super Unleaded is down to $3.49 and E85 went up to $3.29, it doesn’t make sense. I have also tried Seafoam as well as several other fuel saver products and did not see any difference.
Over the road, truckers have been trying various deflectors underneath and on the back, but I have not seen anything that has been beneficial for aerodynamics on an RV. Maybe our readers have more tips they can share in the comments below. Readers?
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Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
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