Just got back, and I mean I'm 3rd beer deep after getting back from a 14hr trip one way, 28hrs total but that's over a week to S.C.

We took my dog, Jasper, this time and needed room so we got those canvas car top carriers... BAD IDEA! 14mpg was the worst I got, 16.7 was the BEST.... Opposed to 22/25mpg last year.

Only thing in the top carrier was 3 duffle bags down and back...

Most likely aerodynamics came into play with a big parachute up there but just wanna let everyone know before vacation season what to expect! Look for those Piggypack or Piggy Back's whatever there called or get a trailer hitch carrier if you don't need to open the back door much.

Just an FYI... Have a good summer!

I've noticed a little hit to the fuel economy with mine (maybe 2 mpg).  But it is hardplastic that is semi-aerodynamic.  I'm sure a bag flapping on the roof is much worse.

Wow...oy, I got 16mpg pulling a trailer for 3 hours on the highway with OD off.   Frankly I think I'd rather just get a small trailer and pull it than have a roof thingy.

Side note - I've noticed in the last year that all the vehicles I've seen driving around town with crap on their roofs all the time (bike racks (with bikes sometimes), canoes, these cargo pods, storage racks, 10 lights, etc etc) seem to be going bald lately.

He, he... I noticed alot of BIG trucks, got smaller... Seems alot of the swamper runners switched to all season and smaller diameter.

Yea, at those MPG readings I'd rather be driving something larger. Filled up today, I'm back up to 21mpg. Looked into the Yukon's (17/21 as opposed to my 18/22 EPA rating) but I'll wait to see what the new XL7 delivers. I know it's a CAR in the purist sense but I think Suzuki went to that drivetrain format for better mileage in a bigger vehicle, we'll have to wait and see what the numbers say. Then again that was probably the last time we make that trip for a few years.

One nice thing about the XL7 is that you can turn your mirrors up and in far enough to see what's on the roof, it was flapping and the shadows we saw looked like a parachute. So defenitely DO NOT USE THEM on an XL7 unless your planning on spending double for gas!

I'm sure those hard shell aero models would be a better bet. But the bag cost me $20 and we needed the space and the back door needed to open to let the dog out to go wee wee. So that $20 probably cost me an additional $100, since we filled up 4 times down and 5 back, usually it's 3 times each way.