I noticed my 2011 has a lower longer and wider air dam under the truck than my 2010. I wondered if anyone swapped one and noticed the fuel economy? I know the Tahoe guys are installing the longer Hybrid air dams on regular Tahoes for fuel economy. Something about blocking that air from tumbling under the body...

 

Swapped a 2011 front spoiler to my previous 2009 STX (which had none) - was a direct-bolt-on, plug-and-play.

Noticed little to no difference in MPG.
.

 

Took my lower dam off. No difference in fuel mileage. Looks better off.

 

Whoa...........

GDMJoe might say......... If that was a funny car all that extra air underneath might cause the beast to lift off the ground and go skidding down the track on it's side. Unless it's clean and perfectly polished between runs.

Ok, all kidding aside (Sorry Joe) ....... for any of you who are confused, this is a result of Post 12 in thread https://www.f150online.com/forums/20...82515-mpg.html

I had mine off a while back, and saw no appearance gains what so ever. It's not eating any groceries under there, so I put it back on.

 

I took mine off when I installed my winch mount in the bumper. it kept scraping on stuff off road so i just decided to leave it off..i ain't noticed anything different with the MPGs.