We like doing dedicated fuel-economy runs on a real-world loop to give us an idea of how these pickups will work for consumers. We go to great lengths to find sizable routes that offer a good mix of city, highway, rural and congested driving so that we can deliver the most realistic overall mpg results.
At the end of our two separate drive loops (one done with a trailer and one without), all three one-ton turbo-diesels were close to one another when driven empty, with the Ram 3500 finishing just ahead of its two competitors with a calculated 16.31 mpg. The three were separated by less than 2 percent. However, with trailer in tow, the GMC Sierra 3500 did a much better job than the Ford F-350 or the Ram with a best fuel economy calculation of 7.76 mpg, which was more than 10 percent better than the Ford and 7 percent better than the Ram HD.
How We Did the Testing
Our home base for this Challenge was Ann Arbor, Mich., so our route wove through many cities and townships in and around the Detroit area. We topped off each pickup with fuel at the same gas station, using the same pump and same filling methods for each, allowing the pump mechanism to click off automatically the first time; then we'd manually fill with one more click after that.
We ran our 150-mile loop twice: once without trailers and once equipped with our 16,000-pound engineering trailers, which included a forward-facing 64-square-foot windscreen to replicate an average storage or camper trailer frontal surface area. We had three rotation spots on our route to change drivers (who were our judges) to make sure each pickup-and-trailer combination got the chance to moderate each driver's weight and driving habits.
Cars.com photos by Evan Sears
Ford F-350 Super Duty 6.7L V-8 Power Stroke TD
GMC Sierra 3500 HD 6.6L V-8 Duramax TD
Ram HD 3500 6.7L I-6 Cummins TD