Why you don't get EPA rated MPG.

[Granite2WD]

I found a website (https://auto.howstuffworks.com/fuel-efficiency/fuel-economy/28004-epa-fuel-economy-explained1.htm) that explains how the EPA calculates the highway rating. What stood out to me is an average speed of 48 mph and a max speed of 60 mph during the test.

I don't know about you, but when I think about "highway" I think of 65 mph. Definitely not an average of 48 mph. For how aerodynamic a truck is, this makes people's complaints about fuel economy make more sense.

The "highway" program, on the other hand, is created to emulate rural and interstate freeway driving with a warmed-up engine, making no stops (both of which ensure maximum fuel economy). The vehicle is driven for 10 miles over a period of 12.5 minutes with an average speed of 48 mph and a top speed of 60 mph. Both fuel economy tests are performed with the vehicle's air conditioning and other accessories turned off.

The "city" program is designed to replicate an urban rush-hour driving experience in which the vehicle is started with the engine cold and is driven in stop-and-go traffic with frequent idling. The car or truck is driven for 11 miles and makes 23 stops over the course of 31 minutes, with an average speed of 20 mph and a top speed of 56 mph.

 

[Granite2WD]

I think their 48 mph average "highway" test should be called "country."

They should have a 65 mph average test called "highway."

 

[SD Rebel]

Also FCA blanket issued their mpg EPA ratings across the board over various trims models regardless of axle ratio or tire size. They could have made exceptions but didn't.

Such as GM, where they lowered the EPA rating on their Trail Boss trims because they know they would be noticieably lower than the majority of their models. The Trail Boss comes with 32" Duratracs A/T tires and higher axle ratios.

The Rebel comes with even larger 33" Duratracs and a rather high 3.92 axle ratio. Yet the window sticker still states the same MPG as a Tradesman with 30" street tires and 3.21 axle.

As for someone who is familiar with leveled trucks on 33" tires, I knew what the expect. But there are a lot of first time buyers with RAM, and I can imagine the shock of someone who buys a Rebel thinking it will get 16 city / 22 highway when in the real world it returns 13 city / 17 highway. This applies to those with Sport trim 22" wheels and 3.92 axles as well.