Thule box Explorer mileage

[spitfisher]

i reset my fuel economy display,when I jumped on highway north of Boston, heading into NH, set cruise on 74 mph. The road conditions were wet, low Volume traffic, with some slight hills and a couple roll thru toll booths.

The Thule box I own is their largest 21 cubic feet. 96 inches long, 36 wide & 15 inches tall.

In the over 40 miles with my 2011 XLT 4wd, Driven in the above conditions my average 21.7mpg

I was surprised, I thought it would have dropped considerably lower.

 

[corkey]

usually Thule boxes are pretty aerodynamic and with the slope of front window bringing air up and the sloped front of the box it may actually contribute a bit to the aero characteristics of the Explorer not adding much drag,
post a pic of it from the side , and follow the lines,, see if it really adds or continues the line of airflow,,

 

[spitfisher]

My box is the longest/largest they make it over hangs the top of the windshield, I can't see while driving.

 

[Bill #5 Explorer]

40 miles is hardly enough to get a true picture. Especially without a comp.

FYI, when I want the best highway MPG's I fold in the electric side mirrors. My MPG's jump to over 30 on long trips.

 

[spitfisher]

40 miles is hardly enough to get a true picture. Especially without a comp.

FYI, when I want the best highway MPG's I fold in the electric side mirrors. My MPG's jump to over 30 on long trips.

I disagree.

40 miles at a constant speed (74 mph) on highway, a section of highway that is neither flat nor has steep grades is a fine scenario for average highway mpg. this exercise was to see how much impact a box on the explorer's XLT 4wd highway mileage, which according to my average was just less than 1 mile MPG. Something that I was curious about.

I do agree that turning in the mirrors, although I would never consider driving the distance required to see a measure able fuel savings or MPG that could be noted. Turning in the mirrors is 1 element, the antenna removal, cross bars, washing the car, keeping the windows shut and the removal of non essential fluids and weight would give even a further accuracy. I was not interested in that data, to me those are not realistic driving conditions.

 

[mjstx]

Y'all are nuts. Are you seriously discussing folding mirrors for max MPG? What does that yield? .05 more MPG? Vs the trade off for safety? Not worth it.

If MPG is that important you're in the wrong vehicle.

- Edit: just saw some of the sarcasm above that I didn't see the first time. My bad

 

[mjstx]

OP - I just did a 2500 mile trip in my v6 4wd. We had an 18 cubic foot Yakima box on top and averaged just shy of 20mpg on the trip. This included a few hundred miles going 80+ where we averaged around 16, and several trips up and down mountain passes for skiing.

Overall I don't think you'll see those #s over the long haul, but it's not that far off of what I experienced.

 

[Bill #5 Explorer]

I disagree.

40 miles at a constant speed (74 mph) on highway, a section of highway that is neither flat nor has steep grades is a fine scenario for average highway mpg. this exercise was to see how much impact a box on the explorer's XLT 4wd highway mileage, which according to my average was just less than 1 mile MPG.

I'm sure you do. But, the only/best way to see the impact of the box would be to compare it to the same scenario without the box, as well. And to actually calculate the miles traveled devided by fuel burn. The digital readout is accurate, but not a true snapshot.

 

[gpzrider]

I did a 4500 mile road trip in Dec/Jan with a large Thule box on Yakima bars. Averaged 14.9 from LA to Portland. Portland to Wenatchee, WA was 15.9. Wenatchee to Missoula was 15.9. Missoula to Swan Valley, Id was 16.9. Swan Valley to Salt Lake City was 16.9. SLC to LA was 17.9. All miles were 8 to 10 mph over legal limit.

I did a 40 mile test with and without just Yakima bars and it was 19.6 with the bars. 21.6 without the bars. Coming and going in the same direction. No hills worthy of mention. 2012 Limited 4x4.