Ok...time for the haters here...lol! Here's a comprehensive list of my fuel economy with my truck.
I have a 2023 Silverado 1500 with the 6.2L gas, 10-speed auto, and 3.42 gears. It also has the "Max trailering" package on it (rated for 13,300# trailer). I use 87 octane fuel in it. "Highway" speed to me is usually 72mph, regardless of what trailer (or none) I tow.
No trailer/empty around town is 19-ish. Highway is around 23. Sometimes higher or maybe down to 22 sometimes.
With my 6x12 cargo trailer on the highway, it's around 12 mpg. Empty or loaded.
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When I pulled my flat trailer with the avatar car to Florida from Michigan, I averaged 14+ for the trip down I-75.
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Now step up to my 24' enclosed car hauler, and the fuel economy is the same loaded or unloaded. The trailer is 4400#'s empty and I've had it to 10,000#'s loaded (trailer is rated to 12,000 #'s). Pulled this thing 4 times Michigan to Florida and back hauling cars or belongings (junk as my wife would say!). Highway speeds 72 mph: 7.5-8.5 mpg.
Slow down to 65 mph: 9.5-ish mpg.
Note it is a v-nose trailer.
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As you can see, the 2 trailers with big frontal area hit the fuel economy due to windload as weight doesn't do much. Whether this truck or the Rams, a gas engine has to protect the converters so the bigger windloads force a lot of time in protection mode i.e. run rich to cool the converters. Just a fact of life diesels don't have to contend with.
Note I have also pulled my flat car hauler with a Silverado 1500 with the 3.0L diesel - what a GREAT package! Detroit to Columbus OH to the Mopar Nats was 20 mpg's. Same when I would pull it to Milan Dragway (about a 110 mile round trip). With no trailer, and to Florida and back (about 10 trips or so), was always 31-32 mpg's. And the driveability of the diesel is simply phenomenal. Love'em!
That's my story and I'm sticking to it...