Generally adding a loaded roof rack to your car will lower your gas mileage by at least 10 percent.
Roof rack gas efficiency.
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.
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.
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.
The roof rack mpg experiment he compared the gas mileage of his car at 54 7 mph 88 kph with 1 no roof racks 2 an empty roof rack and 3 a mountain bike on the roof rack.
In fact it significantly cuts your highway mileage all the time it s installed whether there s weight up there or not.
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.
Adding any rooftop carrier cargo box or ski rack doesn t come free.
Their study was published recently in the.
Using a 2013 honda accord and data provided by consumer reports an empty roof rack will increase the amount you spend on gas by 12 compared to no rack at all assuming highway speeds.
A two bike rack with wind deflector will increase your gasoline costs by 36.
Mileage went from 41 mpg at 65 mph to 40 mpg.
I am somewhat suspicious of this first figure but it s possible.
According to a new study by yuche chen and alan meier published in the most recent issue of energy policy roof racks are responsible for 0 8 of light duty vehicle fuel consumption in 2015 corresponding to 100 million gallons of gasoline per year.
Beyond that the two items tested with the least impact on gas mileage were the paddle board and thule luggage carrier both of which caused about a 19 percent decrease in fuel economy or 5 5.