An increase in vehicle drag implies that the truck must work harder to keep moving, which means an increase in fuel consumption. A compromise with this type of cover is a lack of vertical space in the truck bed to use for hauling. They provide moderate security and hide anything that may be laying in the truckbed.
A cover for the bed of your truck. You really should consider an Undercover Truck Bed Cover. This is great for access to the cargo too, plus it's secure if you lock the cover.
Here are your three choices if you want a hard bed cover. Truxport Tonneau Cover by Truxedo For custom wheels and auto accessories Auto Accessories
The Truxport tonneau cover has a built-in latching system under the rear of the cover to keep your cargo area more secure especially with a locking tailgate. These covers are not a universal fit tonneau. I will start off with some of the features of this soft tonneau that is arguably the best selling soft tonneau cover on the market.
It's better because of the modern material used to build it. You get a lighter, stronger, less bulky hardcover at about the same price. Isn't that one of the reasons you're looking at a hard bed cover? The lids are all but indestructible, so you still get great security when you lock up your bed.
The Undercover bed covers are very strong, even though they are light. The deal is that Undercover was the first company to build a hard, hinge-forward bed cover using more modern materials. Bishop, K. (2006, October 9). American Roll Tonneau Cover Review.
Bishop, Ken "American Roll Tonneau Cover Review." American Roll Tonneau Cover Review. I must say that this has to be my favorite manual retractable tonneau cover. If you have a bed liner you will probably have to make some cuts in the liner where the clamps need to go and again at the tailgate where the lock of the tonneau cover ends up. No big problem though.
This cover is backed by a 2-year warranty which is a real plus for a retractable tonneau cover. Truck covers the USA designed and manufactured the clamps themselves especially for this cover. Find out more about the Roll-N-Lock Tonneau Cover Also check out the Undercover Tonneau Cover
You will not have to unsnap, unpeel or unseal Velcro to get access to your truck bed.