MPG hit? More or less Aero designs, how do they compare? (Science and data inside)

Also remember that unless you’re just adding a fiberglass camper shell, which isn’t very heavy, a proper camper full of camping stuff is going to blow up your curb weight substantially, and that’s going to kill your mileage as well.

 

True for stop and go city driving but not so much cruising along. The shape change and rake of the truck are going to be the most significant impact on the cruising efficiency. Rake (or attitude) of teh vehicle is something that's not accounted for in the sims.

 

I have a data table that includes each time I fill up, how far I drove, how much gas I put in, etc. I also make a note if I had my rtt and rack on/off, tonneau cover on/off, and when I put my current cap on (a couple months ago).

I don't make note of what kind of driving I did, city or highway, or how much weight I've had.

Interestingly, I did a road trip through to Oregon and back to Colorado with a rtt on billie bars over my tonneau cover with quite a bit of weight. Looks like it didn't change my averages much, it goes from 16-22 mpg.

With my cap on, I've filled up 4 times with average of 17 and 20.

People like to complain about their mpg, but it really seems to change depending on driving being done.

I guess my main point it, even with a collection of data from users on here, trying to figure out mpg based on aerodynamics without factoring in other variables will be nearly impossible.

The only way I could think of as basic of a comparison as possible is do use 1 truck with all the different configurations for the bed on the same loop with the same weather, etc...

Graph of my data for reference