You don't need to be a physicist to understand how strong wind resistance can be while you're driving at high speeds. This isn't a problem if you drive an aerodynamic car, but if you're driving a truck with a trailer attached, you're losing gas efficiency. The issue is the trailer's large, flat surface area. Since the wind cannot get around the trailer easily, your truck will have to utilize more power and fuel to keep moving. Wind deflectors help decrease wind resistance by redirecting air flow over the trailer. This, in turn, reduces the amount of power necessary to move the trailer and increases fuel efficiency.
Position the air deflector as far back on the roof of your truck as possible. You want to shorten the distance between the deflector and the trailer to ensure the trajectory of the wind flows over the trailer.
Center the air deflector so it is positioned in the middle of your truck's roof. A precise middle position will deflect the maximum amount of air that your trailer would otherwise come into contact with. Positioning the air deflector too far to the left or right will leave parts of your trailer exposed to straight-on wind resistance.
Firmly plant down the suction cups on the bottom of the deflector base to the roof of your truck. Use a damp rag and rub the inside of the suction cups if you're having trouble creating enough suction. Give the base a moderate tug or push to make sure it's secured.
Attach the mounting hook to the weather stripping above the driver and passenger-side windows. Feed the nylon straps on the air deflector base through the mounting hooks and lock them in place. These nylon straps will prevent the air deflector from dismounting your car if the suction cups fail. As such, make sure the straps are locked in position.
Adjust the angle of the air deflector if the model you purchased has this feature. Increase the angle of the air deflector for tall trailers. You only need to raise the air deflector high enough to divert air flow over the trailer.
