The 2015 Ram 2500 HD 4×2 Longhorn is next up to take the highway mpg test. This truck is propelled by the 6.7L I6 Cummins turbo-diesel engine that makes 370 horsepower and 800 lb-ft of torque. The 6-speed automatic transmission sends the power down the line.
Why do the highway fuel efficiency run? This is a test with fewest variables and least human interaction. Fill up at the fueling station, get on the highway, set the cruise control, and study the results. Here are the details.
The route consists of a 21 mile stretch of I-25 just north of Denver, Colorado. It begins at the gas station near exit 229, then goes north to exit 250. This is where we turn around and head back south to the same gas station. The round-trip is approximately 43.6 miles.
Once we merge onto the highway and set the cruise control at 65 mph – the run is a relatively level stretch of highway with a few rolling hills. The elevation is just over 1 mile above sea level. We then turn around at exit 250, where there is only a stop sign, and come back to the gas station (again with cruise set to 65).
There were two people in the truck and a set of camera equipment. We added approximately 440 pounds in the bed to compensate for missing one person and the truck being 4×2 (we usually do these tests with three people and 4×4 trucks). The outside temperature was 58F with a slight wind from the north.
Dually HD Diesel – Highway MPG
| 2015 Ram 2500 | |||
| Model | CrewCab 4×2 Longhorn | ||
| As Tested $ | $61,535 | ||
| Engine | 6.7-liter I6 | ||
| Transmission | 6-speed | ||
| Power (hp / lb-ft) | 370 / 800 | ||
| Axle Ratio | 3.42 | ||
| Test Load (trailer + ppl) | 940 lbs | ||
| Ambient Temp F | 58F | ||
| Route (mi) | 43.6 | ||
| Elevation Avg (feet) | 5,100 | ||
| Highway MPG | 24.73 |
Check out all the details in this TFLtruck mpg test video.
Andre Smirnov is a life-long automotive enthusiast, writer, reporter, and software engineer. He has been a contributor at TFL since 2011.
