30 4mpg two front windows a third open 30 3mpg roof bars and laden roofbox 30 2mpg two front windows totally open 29 7mpg four tyres.
Most fuel efficient roof box.
The control test the tourx without roof rails.
30 5mpg astra s baseline fuel economy.
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.
Bengt halvorson april 15 2015 comment now.
If fuel consumption is a concern invest in a streamlined box which will cut through the air more efficiently.
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.
But if you.
The quick grip mounting system is both tool free and very easy to use and with a bit of practice you can get the box on and off the car in about 5 minutes.
The box has tapers to a point and employs diamond textured aero skin to help it slice through the air and protect vehicle fuel economy.
It s impossible to give an exact figure because it depends on so many factors but britain s biggest roof box manufacturer thule states that your mpg is unlikely to decrease by more than 5.
Roof boxes fix to your roof racks either with a basic u bolt system or a claw style attachment.
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.
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.