We're planning a month-long cross country trip this summer with our 2007 Yukon XL. It would be nice to have more storage for the tent and sleeping bags. I have wondered about using a rooftop cargo carrier. But, I am scared of killing my mileage. Does anyone have experience with these who can tell me how much they cut MPG?

Thanks,

< 10 % on our Sienna van.

Ours is pretty aerodynamic for a roof-top unit. There are a number of styles.

It depends. Some of the roof top carriers are well designed for aerodynamics but they're also very expensive. Unless you use it all the time, the price might well be more than the extra gas you'd need to buy to handle a square box. Lets say you spend $150 more for a good carrier. At 3.50/gal, thats worth about 42 gals. You're going to have to drive a long ways to use an additional 42 gal.
For a unit that you'll be using for years, it's probably worth it. But, if you want it for just a few trips, no way.

Something that WILL cut your mileage is a flapping tarp. It's like dragging a parachute. Tie it down tight. Better yet, cover it with a cargo net.

I should mention that a hard top carrier is far more convenient than having to untie a tarp every time you want something out of the thing.

In 2000 I took my kids out West on a similar trip. Mt Rushmore, Yellowstone, Tetons, RMNP, into Utah through Moab, Monument Valley, . I felt like Clark Griswald. We had stuff tied on top of our 96 Astro van and hanging off the back in a hitch haul. We seriously over packed. We packed for several weeks of camping without realizing they have grocery stores in the west too. I lost about 2 mpg compared to usual. A lot of that was probably more the weight than aerodynamics.

If I were going to do it again it would be with a clamshell type of carrier. After a few days we figured out what we really needed. What we could throw in the trash we did. The stuff we didn't need, and couldn't trash, went on top and wasn't touched again till we got home.

I've made the West trip a few times before. The last time was 2008, when my wife, 2 boys and I car camped in my Yukon. We kept it as bare bones as possible. But, a tent and sleeping bags alone eat up a lot of room and we were pretty crowded and had to keep our stuff perfectly organized. After every night's camping, we had to unload the truck and repack it exactly. Now that the boys are teens and take up more room, it would be nice to not be so crowded.

The last TIME we drove around 7,500 miles and got about 16 mpg. So, I figure every 1 mpg lost would cost roughly about $100 more in gas.

Have you thought about a hitch hauler? They are pretty cheap (walmart, harbor freight, etc.).

This thread reminded me of my cross country summer trips with my mom and dad in the mid 60's.

12' Penn Yan cedar boat, 10 hp Johnson with a 6 gal fuel tank, fishing gear, tent, sleeping bags, two burner Coleman stove, lantern, ice chest, and clothes ...

All packed, for the most part, in the trunk of a four door Chevy Impala except for the boat, motor and gas tank. My dad made a nifty bumper bracket for the motor and gas tank that was also the rear vertical support for the boat.

Simpler times. We didn't have all the gear you need nowadays.

Somehow, I can fill up the back of my Chevy P/U with a camper shell on it, chock full, for a one week out of state hunt.

We have one of those and thought about putting some kind of box on it. But, it's a hassle accessing the cargo area of the truck with the deer rack in place. I'd hate to have it in the way for a month. But, I haven't entirely ruled it out.

Isn't that the truth! We always fill it up for our deer hunts!

We used a Yakima unit on a VW Jetta diesel wagon for a couple of years. Unless there was a ferocious headwind, we could hardly tell the difference in mileage. We averaged 40+ mpg on the interstates and the tank to tank differences in mileage due to topography and wind exceeded the reduction in mileage due to the car top carrier.

Thanks! I find your experience encouraging! I just don't want to find out the hard way that's going to cost me 3 or 4 mpg when I'm only averaging 16. Like you, I experienced big mileage swings depending on topography, anywhere from 12 to 20.

I thought very briefly about one when I had a Suburban. I declined when I saw that I'd have to unload it completely to open the rear doors. They do work, though. My former boss hauled a piano 500 miles on one on the back of a 3/4 ton Suburban.

I have a roof rack basket and a hitch hauler for my jeep liberty. I leave the roof hauler at home anymore and just use the hitch hauler. The roof rack kills the gas mileage and the wind noise gets bothersome after a while. I haven't had any problems with the hitch hauler, I don't find it gets in the way that much. My liberty back glass lifts up though, so I can get in the cargo area without opening the rear gate.

What about a small box trailer? I 've tried a roof carrier and a hitch hauler but in most situations prefer a small trailer..

I am not a fan of trailers. They force me to slow down too much driving when traveling long distances and make parking problematic, particularly in big cities.

I like the idea of the roof carrier; but, I am afraid of a big hit on mileage. With our hitch hauler, you can get in front of it, but, have to do the limbo to get the rear door open!

I've driven mega miles with trailers of all sizes, including semi's, doubles, and triples. I'm completely at home with one. However, there are trailers made for easy towing and trailers that should be scrapped. The 2 biggest problems: too narrow and too short. A narrow trailer that isn't easily seen in the mirrors is very hard to back. By the time it comes around to where you can see it, it's too late to correct and you have to pull forward. A short tongued trailer is even worse.

^ this. I have not driven mega miles with trailers, but this is true in my limited experience.

I would much rather have a narrow, short tounged trailer in tight quarters than a wide, long trailer. they track better on corners and don't sick out so meeting vehicles on narrow roads is a breeze.

Going forward isn't the problem. It's going backward.

We take my 07 Yukon XL 11 hours each way for our annual Spring Break Hog Hunt, with a hitch & haul. I get the best mileage of the year on that trip. I've never used a cargo carrier, but I can't imagine the mileage being as good. I'll also give a nod to the earlier poster who mentioned wind noise - I'd expect some.

The hitch & haul handles a few rubbermaid containers that hold bulky (but not too heavy) stuff, like clothes, waders, etc. Now, we drive straight down & unload, so we're not trying get stuff in & out of the back regularly. Still, I'd have an even harder time trying to climb & twist up to the luggage rack to get stuff out of a cargo carrier up there.

We have always had 3 of us on the trip, and we've packed the truck to the gills every time with gun cases, coolers, food, & junk. This fall we're going as a party of 4, so we're going to rent an 8' enclosed trailer.

If you do decide to go with a a cargo carrier, I'd look first at a sleek Thule-type bullet carrier, rather than one of those X-Cargo cubes, or the rubber-sack-looking things I see on minivans that are screaming north on I-75 out of Florida.

Good Luck,

FC

He is talking primarily about ease of backing up, not pulling down the road.

backing up is not impossible but can be largely avoided with a little forethought.

This is very similar to what is on our van, FWIW.


Mileage with: 22+
Mileage without: ~24

Speed limits here are 65 and below. Speed will be a huge factor.

Should be similar to your van, it is your van?!

Oops. Forgot the picture!

LOL.