Three-Quarter-Ton Gassers Loaded Testing
Just about every issue we felt in this category unloaded was magnified with our 10,000-pound trailers in tow. The Ford was a beast to control in two-wheel drive with our trailer, while the GM truck felt smoother still.
All three did well when in tow/haul mode, making a noticeable difference in shift points and how long each gear is held. Again, the Ram HD felt to be the strong puller but was not the most stable-feeling down the track. The Silverado felt the most confident when accelerating, meaning the most stable tow vehicle and most comfortable with the load.
Both Ford and GM transmissions were quite aggressive when downshifting after the finish marker with trailers, but it’s worth calling out the cool real-time gearing display on the Ford that tells you the exact gear the truck is in at any moment. This was a huge help when trying to slow down 17,000 pounds at the end of a racetrack.
With a 10,000-pound trailer hitched to the back of the gas trucks, the track numbers immediately changed, though the results were almost identical to when the gas haulers were unladen. All of the trucks were about 20 mph slower at the 1,320-foot mark and required about 7 more seconds to run the distance.
The Ram 2500 remained the dominant truck. Again, it was surprising because we expected its transmission to be a handicap, but on level ground the Chrysler rig was “in the zone.”
The Ram was 0.6 seconds faster than the Ford and 1.4 seconds faster than the Chevy from zero to 60 mph. It was still the fastest truck at the quarter-mile mark, charging to the finish line at 64.01 mph versus 63.61 for the Ford and 62.24 for the Chevy.
The same characteristics about the Ram’s weight and powertrain that we cited above applied when there was 10,000 pounds to lug.
We noticed that the Ram exhibited some wheel slip at the start of each wide open throttle run, but it wasn’t enough to dampen performance. The Ford F-250, which had traction control, showed some axle tramp coming off the line. The GM truck, though slower, managed all of its loaded launches gracefully.
Three-Quarter-Ton Diesels, Loaded Testing
Like the gas trucks, we tow-tested at Milan with precisely weighted 10,000-pound conventional trailers. We’re not sure we’ve ever towed trailers so evenly weighted over the wheels or balanced front to back. They offered a good test for each of our turbo-diesels.
As before, we had some trouble modulating the traction of the Ford (we suspect turning off the system may have given us the extra control we needed, but that makes us wonder why it’s there in the first place). And again, once the Ford found its grip, the Power Stroke felt to be a strong puller. The Silverado 2500 needed just a touch of finesse off the line to get it moving at wide open throttle, where it clearly separated itself from the group. Likewise, when slowing down the 17,000 pounds of metal shooting through the end line, the Duramax exhaust brake and tow/haul mode did a superior job of slowing with back pressure and aggressive downshifts to make our end-of-the-track turn a non-event.
Of the group, the Ford seemed to rely on the transmission to do most of the slowing work, while the Ram HD had the strongest-sounding exhaust brake of the group (very Mack-like). The Ram 2500 was the player of the challenge that was left behind, doing a great job getting up to 60 mph, but having very little left after that.
This time, we started to see the separation we were looking for between the trucks. The Silverado improved its performance over the other two trucks, thanks to its best-in-class power settings and rear axle gearing. It was also the smoothest truck off the line again, having little difficulty managing power out from the engine to the tires without an intrusive traction control system.
The Silverado hit 60 mph in 17 seconds, more than a second ahead of the F-250 and 3 seconds faster than the Ram 2500. The Silverado was also fastest at the quarter-mile marker, and it carried the highest speed.
With Ford’s 6.7-liter V-8 now rated (as of Aug. 31) at 400 hp and 800 pounds-feet of torque, it would be very interesting to run this test again. It might not make much difference because like the first run, the Ford showed difficultly keeping its rear axle planted at wide open throttle.
The Ram suffered from loose tires at launch, and its Cummins engine started to show signs that it was having difficulty not getting bogged down after each gear shift.
One-Ton Diesels, Loaded Testing
Testing the strongest trucks with the biggest trailers was probably our premiere event of the day (unless you count the regular cab Duramax “prototype” the GM guys brought to the track).
The F-350 dually gave us our best launch of the day here and felt the strongest off the line. From the seat of our pants, it felt like the Denali and F-350 were the more powerful trucks down the track. However, the Ram HD Cummins was the loudest, working hard in the higher gears to make it to the end of the quarter-mile before its zero-to-60 time. In fact, the Ram HD Mega Cab dually hit 60 mph at the exact moment it hit the quarter-mile marker at 24 seconds flat.
The Sierra Denali 3500 pulled strong after a small slip at the start line but was able to get its six-ton trailer up to 60 mph in 18.8 seconds, a full half-second faster than the Super Duty. The Super Duty’s transmission seemed well-suited to bring the fight to the Denali after 60 mph. In fact, by the time the F-350 got to the quarter-mile marker, it had closed the gap with the GMC to almost nothing. The best time for the Denali was 22.3 seconds, while the best time for the Ford was 22.4, and we’re guessing if this were a half-mile flat-tow head-to-head test, the Power Stroke would have likely overtaken the Duramax in the next 200 feet.
Be that as it may, it’s hard not to like the strength and muscle of the GM and Ford duallies, and it’s clear the Cummins needs to bring a bigger gun to the next track fight.