[Big Dave]

My truck came with telescoping trailer-towing (TT) mirrors. Unless pulling a trailer, I always run with them pulled all the way in. They are flat-out the best side-view mirrors there are in terms of seeing what is behind you. With my totally opaque bed fairing I need them. These are OEM optional mirrors.

But they are enormous. They have a little effort at rounding off the forward side, but they have to impose a lot of drag.

Another option is the factory "paddle" mirror. They are smaller and do not extend out as far from the cab. They don't give you quite the view to the rear, but it is good enough.

There is a lot of thought in the pickup truck community that the paddle mirrors should give better MPG.

Seems intuitive, but how much. We have also seen some counterintuitive results from aero mods. Only one way to answer the question. Road test.

After six weeks and 2539 miles of my circuit in nearly constant mild summer weather on flat terrain running my usual test circuit (35% urban/suburban, 30% Interstate at 1700 RPM (69 MPH), 35% stateroads at 1450 RPM (60 MPH) with some moderate hypermiling (mostly coasting and timing lights plus bump-and-coast in town) I got a result.

The paddle mirrors delivered 0.66 better MPG or a 2.5% improvement.

TT mirrors: 26.32 MPG
Paddle mirrors: 26.99 MPG

Note: I ran the test without my air dam. It is undergoing a redesign, so I am down from last summer a bit. I did not get to do a pure Interstate run where aero improvement would have really shown.

Just thought you guys would like to know.