How Much Do Roof Racks Affect Gas Mileage

He found that compared to the baseline of no roof rack the empty rack reduced his mpg by 12 7 and the roof rack with a bicycle reduced it by a whooping 27 3.

How much do roof racks affect gas mileage.

Their study was published recently in the journal energy policy in a paper titled fuel consumption impacts of auto roof racks. 5 9 l 100 km approx. 42 mpg roof rack with thule dynamic 800 aerodynamic cargo box. Roof rails will not effect mpg cross bars may to some degree and mostly is not only while traveling at a freeway speeds.

Generally adding a loaded roof rack to your car will lower your gas mileage by at least 10 percent. So if your car usually gets 30 mpg on the highway and you add a full roof rack your highway gas mileage will drop to 24 27 mpg. They found that in 2015 roof racks nationwide were responsible for 0 8 percent of light duty vehicle fuel consumption or 100 million gallons of gasoline. 40 mpg roof mounted thule xtender 739 ski carrier with skis.

Mileage went from 41 mpg at 65 mph to 40 mpg. A five percent change in fuel economy is worth 75 each year or 375 in five years. 5 6 l 100 km approx. The control test the tourx without roof rails.

Off the showroom floor the regal tourx gets 21 miles per gallon in the city and 29 mpg highway for a combined fuel economy of 24 mpg. Some drivers may see their gas mileage drop by as much as 20 percent depending on vehicle type and type of roof rack. Their study was published recently in the. This editor many years ago in a move across the country to oregon from michigan found that the highway mileage of a four cylinder accord dropped from more than 40 mpg down to 32 mpg with a.

If most of your driving is freeway and you re worried about 2mpg then take the cross bars off when not in use. Drag coefficient increases by speed squared. The empty roof rack had a nearly 2 percent impact on fuel economy which translates to a little more than three quarters of a gallon of gas. And since air resistance increases exponentially with speed the difference would have been even bigger at 70 mph many people drive at that speed.

I ve put cross bars on two different odys with no measurable effect on mpg. Some roof racks have cross members that can be unscrewed and stowed inside. They found that in 2015 roof racks nationwide were responsible for 0 8 percent of light duty vehicle fuel consumption or 100 million gallons of gasoline.