Yes. Any added roof load increases drag . Aero-shaped bags help a bit, but expect slightly worse mileage—especially on long highway drives.

Question 1

Do I need a roof rack to use a cargo bag?

Accepted Answer

Not necessarily. Many bags come with straps or clips that work with bare-roof vehicles. Just make sure they won’t damage your door seals or paint.

Question 2

Are rooftop cargo bags really waterproof?

Accepted Answer

Some are, some aren’t. Look for welded seams, covered zippers, and thick materials. “Water-resistant” usually isn’t enough.

Question 3

How fast can I drive with a cargo bag?

Accepted Answer

Most manufacturers recommend a max speed of 60–70 mph. Drive slower in high winds or with a heavily loaded bag.

Question 4

Can I use a cargo bag on a sunroof?

Accepted Answer

Generally not a good idea. It puts pressure on the glass and can cause leaks. Avoid unless your sunroof is reinforced and completely sealed.

Question 5

Will a cargo bag affect fuel economy?

Accepted Answer

Yes. Any added roof load increases drag. Aero-shaped bags help a bit, but expect slightly worse mileage—especially on long highway drives.

Best List

The Best Rooftop Cargo Bag