We don't think there is any more extreme test for a pickup truck to have to endure than taking it where the air is thin and the roads are steep, and that's what the Eisenhower Pass grade is all about. We tested on a 7.2-mile stretch of Interstate Highway 70 in Colorado, from the valley exit at Dillon to the entrance at the summit of the Eisenhower and Johnson tunnels. This stretch climbs more than 2,000 feet and is the worry of every eastbound big-rig trucker.
This stretch of the I-70 is famous for its hair-raising emergency truck runoffs (there were three on our test stretch) and the punishingly steep hill climbs that bring trucks' cooling systems to their knees as engine temperatures reach redlines they've never seen before.
The Ford F-250's 6.2-liter V-8 did the best job of getting the truck and trailer up the hill in the shortest amount of time. Both the Chevrolet Silverado 2500 and Ram 2500 seemed capable of doing the job but not with nearly the control and power of the Ford. It almost seemed like the gross combined weight ratings for the Ram and Chevy were a bit too high in relation to how their engines and transmissions performed. Yes, all these trucks were pulling the same loads, but the Ford was the only one that pulled to the limits with confidence. We'd like to have a little more cushion or "just-in-case" buffer in the numbers.
The Ford attacked the hill at a steady and easy pace, running the 7.2-mile stretch in 9 minutes and 40 seconds, while the Chevy ran almost 30 seconds behind the Ford, and the Ram lagged more than 2 minutes behind the Chevy. In fact, for most of the climb up the hill the Ram downshifted to 1st gear, spinning the engine at 4,500 rpm, marching along at less than 30 mph.
Although we didn't call out and score three-quarter-ton braking testing on the Eisenhower grade, we did experiment with how well each truck controlled its weight on the way down. Many drivers forget that a towing truck's ability to stop its load is more important than how well it can pull that same load up the hill.
We exited the tunnels at the summit of our route aiming for a 45-mph speed limit with our testing range between 35 and 55 (below 35 and we'd speed up, and anything above 55 meant we'd check our speed down). We adjusted the sensitivity of integrated brake controllers on each pickup to a gain of 7.0, knowing that there would likely be some variation. All three trucks have some variation of grade braking available from the transmissions, but we found they are not equal.
During the Ram brake-testing runs, we had to touch the brakes down to 45 mph 10 times to stay within our range, getting the gearing to drop into and stay in 2nd gear. At the bottom of the hill the front disc brake rotors hit 530 degrees. Our F-250, driven in the same manner with the same target speed parameters, required us to touch the brakes on the down grade eight times, with the front brake rotors registering 265 degrees at the bottom of the hill. Finally, our Chevy required us to use the brake nine times (it toggled back and forth between 2nd and 3rd — and when it jumped to 3rd, we always had to brake it back into 2nd) with the front disc recording 333 degrees at the bottom of the hill.
Given the weights involved and how willing each truck was to use gearing to help slow the pickup and trailer combination, the Ford F-250 was the truck that seemed to offer the most controlled downhill run.
How We Did the Testing
We knew we wanted to do something special here, so we opted to run each truck as close to its manufacturer-stated GCWR — meaning all it can carry and tow. Simply put, we wanted to see how well or poorly they performed at their limits. We know most people aren't likely to do this kind of towing (and if they did, they'd probably buy a one-ton dualie turbo-diesel), but how well a pickup does near its limits is likely to say a lot about how well it will do when things aren't so tough.
Our trailer for this event, when empty weighs, about 6,000 pounds but we had two 330-gallon water tanks (each weighing 2,800 pounds) wedged inside, bringing the total weight close to 12,000 pounds, near but not over each truck's stated maximum conventional tow ratings.
The F-250's GCWR is 19,000 pounds; the Chevy's is just more than 20,000 pounds, and the Ram 2500's is just more than 22,000 pounds. We attempted to adjust each max trailer weight by dumping a certain amount of water from each truck or trailer, getting as close as possible to 90 percent of the vehicle's GCWR number.
Cars.com photos by Evan Sears