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How What You Haul (Or Don't) Impacts Gas Mileage

Brian Champagne

Skiiers, ski season is over. As Brian Champagne learned while borrowing a Volvo, if you put your toys away, you can save 12% on your gasoline bill.

The voice of the V90 Cross Country T6 all-wheel-drive wagon that Volvo loaned us is a little harsh sounding. But if you have fifty-five grand for a car, we’d still recommend it.


They supercharged and turbocharged a two-liter engine, that’s the same size as a Toyota Corolla’s, but it makes almost twice the horsepower at 316 while still getting 30 mpg on the highway.


It’s more aerodynamic than the new Chevrolet Corvette, with about half the rear cargo space of a Toyota RAV4.


If you can add on $2,800 more, we recommend the lounge package that includes massaging seats in a Swedish car.


What we don’t recommend is what came on top of our loaner. Volvo made the V90 sleeker than a ‘Vette, but someone mounted a cargo carrier on it. It made it louder in the wind as it created what seemed like a high-school physics aerodynamics problem that we took to Mark Cowley, a physics teacher and department head at Green Canyon High School.


“Terribly inefficient for cars,” Cowley said. “It's one of those if you look at a car, how it’s designed, it’s designed to be aerodynamic to help move through the air without a lot of drag. So if you put two skis on top, or if you put a luggage rack on top, it's one of those that reduces that efficiency the car increasing drag on the car.”


Studies comparing rack off and on published online averaged a 10% loss in gas mileage. Consumer reports threw a rack and a pod on top of a Nissan Altima and saw a 19% drop. 


So why would people leave racks and bins up there when they’re not hauling stuff?


“I think they want to look cool,” Cowley said. “Let everybody know that they ski or snowboard or maybe you’re looking for a vacation go on."


“I don't think they’re cool at all, “ said physics student Porter Levi. Levi said besides the drag… “It looks like you’re in a constant state of being a soccer mom.”


Mileage results look a little better for carrying your stuff on the rear of the car, like in hitch-mounted units.


If you take the rack off your Volvo, you can relax, getting your full gas mileage and a massage.


Brian Champagne grew up in the less-famous Central California but left after starting his television news career there. He worked 22 years in news for NBC, ABC, Fox, and CBS affiliates in four markets. He served as chief photographer for KTXL-TV in Sacramento, but worked in front of the camera, too.