Part 3: [1] [2] [3] [4] [5] [6] [7] [8] [9]
[Intro] [3/4-Ton 7% Grade] [1-Ton 7% Grade] [Diesel v Gas Comparison 7% Grade]
[3/4-Ton 15% Grade] [1-Ton 15% Grade] [Diesel v Gas Comparison 15% Grade]
[F-450 All Grades] [Summary]

Three-Quarter-Ton Gas Pickups - 7% Grade With 10,500# Trailer:

To visualize the hill climbs at Ford's Michigan Proving Grounds picture a single, very large hill cross-sected at different angles by six two-lane concrete paved roads, with gradients ranging from 7% to 60% (yikes!) and lengths stretching from 60-feet to 2,000-feet.

The 7% test distance was 1,476-feet long, or 450-meters according to our British-sourced Oxford Technical Solutions RT3102 monitoring unit. That's 156-feet more than a quarter-mile, or 1,320-feet. Distance is shown in both feet and meters in the graphs that accompany this part of the testing.

For all the runs on the grades at MPG, both truck and trailer were completely on the grade and stationary prior to the start of the run. All the tests were performed 'brake-to-accelerator', i.e., foot brake fully depressed with right foot, then lift and fully depress the accelerator pedal in one movement with the same foot. Sufficient distance was provided at the end to slow the rigs down to a safe speed prior to the top of the hill.

A minimum of three runs were carried out in each configuration tested at wide open throttle (WOT), with the fastest run for each truck used in the results.

NOTES:

Due to space and readability considerations, the bar graphs below only show the test results from 200-m (656-feet) to 450-m (1476-feet). See the summary table at the bottom for full test results from 50-m to 450-m.

All times and speeds measured are shown cumulative over the run.

In the graphs below: the lower a truck's bar is, relative to the other two trucks' bars, in the "Time Over 450-Meters" graph the better it performed. The higher a truck's bar is, relative to the other two trucks' bars, in the "Speed over 450-Meters" graph, the better it performed.

The shortest time required to cover the 450-meter distance determined the best performing truck.

Three-Quarter-Ton Gas Pickups 7% Grade With Trailer Summary
	2007 Dodge Ram 2500 Quad Cab 5.7-L V8 4x4 SRW 5-speed auto 3.73		2008 Ford F-250 Super Duty Crew Cab 6.8-L V10 4x4 SRW 5-speed auto 4.30		2007 GMC Sierra 2500 Crew Cab 6.0-L V8 4x4 SRW 6-speed auto 3.73
Cumulative	Time (sec)	Speed (mph)	Time (sec)	Speed (mph)	Time (sec)	Speed (mph)
50-m / 164-ft	8.98	21.20	8.05	24.09	8.79	23.26
100-m / 328-ft	13.49	27.12	12.07	31.64	12.76	31.64
200-m / 656-ft	20.38	36.09	18.40	38.45	19.25	36.42
300-m / 984-ft	25.99	42.18	23.93	42.76	24.96	41.64
400-m / 1312-ft	31.17	43.46	29.03	45.54	30.06	46.12
450-m / 1476-ft	33.81	43.90	31.47	46.58	32.45	47.70

Three-Quarter-Ton Gas Pickups 7% Grade Assessment:

What a difference adding some gravity made to the contest for the gas pickups. When you look at the performance numbers and truck specs, there's some high drama happening among these haulers in the uphill quarter-mile.

Hauling a 10,500-pound load, the Ford F-250 took full advantage of its Triton V10's stronger, earlier torque peak to sprint off the starting line well ahead of the GMC and Dodge - reaching 50-meters (164-feet) more than half a second before the Sierra and almost a full second ahead of the Ram. The Sierra's gap would probably have been wider if not for its 6-speed 6L90 HD transmission's fast 4.03 first gear, a good foil to the Ford's 4.30 final drive ratio. By 100-meters, even though the Ford still had the lead, both the Sierra and the F-250 were traveling at identical speeds. But as both trucks shifted into third and their transmission gearing became closer to each other (1.55 in the Ford to 1.53 in the GMC) the massive and early torque peak once again proved decisive for the F-250, allowing it to build a bigger lead again at the 200-m mark. The Ford kept an edge on speed until 400-m, when the Sierra finally started moving faster than the F-250. But it was too late for this test's distance. The Ford took the race by almost a full second over the GMC, and by more than two seconds over the Ram.

If the distance would have been longer, it's possible the GMC could eventually have caught the Ford - which would have been similar to what we experienced during the first drive of the 2007 GM Heavy Duty Pickups. This time, though, brute force triumphed cog-swapping finesse.

Part 3: [1] [2] [3] [4] [5] [6] [7] [8] [9]