If you follow our coverage on fuel efficiency you know that real world mileage numbers don t always measure up to the official epa ratings.
Most fuel efficient roof box.
The gear with the most impact were the dual mountain bikes strapped to the roof which impacted the fuel economy by 31 percent or 9 mpg.
The claw attachments make it easier and quicker to mount and remove the box.
Promoted as the quietest most aerodynamic and fuel efficient line of roof racks in the world yakima s wispbar takes direct aim at conservation minded drivers.
Keep in mind that your car uses more fuel when it has a roof box attached our test car used 12 1 more fuel with the roof box fitted than without.
Bengt halvorson april 15 2015 comment now.
A former rolls royce aircraft engineer was hired to take yakima s racks to the next level and we have him to thank for the wispbar s wind cheating aerofoil wing profile.
Roof boxes fix to your roof racks either with a basic u bolt system or a claw style attachment.
For comparison the additional fuel consumption caused by roof racks is about six times larger than anticipated fuel savings from fuel cell vehicles and 40 percent of anticipated fuel savings.
A close second was the kayak with 28 percent or a.