2011 GMC Sierra HD 2500 Denali 4×4 Diesel – Short Take Road Test « New and Used Car Listings

2011 GMC Sierra HD 2500 Denali 4×4 Diesel – Short Take Road Test

Numbers are an obsession in the auto industry. Corporate suits worry about build costs, profit margins, and sales volumes; sports-car fans spend more time watching horsepower counts, acceleration times, and top speeds. But heavy-duty truck enthusiasts live and die by numbers, perhaps more than any other segment of the automotive sphere.

To that end, the 2011 GMC Sierra Heavy Duty—along with its Chevrolet Silverado twin—sees a couple of its key numbers swell to 6635 and 21,700. Those are the highest payload and trailer-weight capacities of the GM HD trucks; the totals for the 2500 truck tested here are 2631 and 16,800 pounds, respectively. But when we finished putting this GMC Sierra Denali 2500 through its paces, it wasn’t these digits that had our spreadsheets smoking.

Quick for a Big Guy

Indeed, a thoroughly overhauled Duramax turbo-diesel V-8 supplies the first pair of staggering numbers: 397 and 765. Those are the 6.6-liter engine’s respective hp and torque counts, the former peaking at 3000 rpm and the latter at 1600. Those two figures delivered the digits that simply blew us away—7.3 and 15.7, as in stopwatch ticks to 60 mph and through the quarter-mile, the latter feat occurring at 89 mph. What we have here is a 7560-pound truck that’s quicker than the first Chevy Camaro we ever tested and capable of hauling most of one in the bed or towing four behind it on a trailer.

Credit for this quickness is also due to the six-speed Allison automatic transmission, which keeps the Duramax spinning at the absolute peak of its prodigious power band while shifting with relative smoothness. (In contrast, the hard-shifting automatic in our long-term Ram 2500 changes gears as though it were trying to rip itself apart.) Most of the Sierra driving experience is similarly pleasant. The steering is nicely weighted and direct without being so nervous as to cause concerns about stability with a trailer aft. The brake pedal, too, feels surprisingly firm and communicative for one meant to be stomped on by work-booted feet and actuating a system responsible for halting 10 tons. Our haul down to 0 from 70 mph took 217 feet, which seems to be the standard for HD trucks, regardless of manufacturer: Of the five we’ve tested in recent months, all are clustered between 217 and 222 feet.

The Sierra is not without its flaws, however. Although a suspension designed to accommodate a one-ton payload atop the shoulders of a four-ton truck is never going to be compliant, there’s a difference between unyielding and uncivilized. Small impacts jostle occupants, but over larger impacts, the front axle feels detached, like it’s rattling in its bushings. “Unfinished” is hardly a confidence-inspiring vibe to get from a work truck.

Huge Truck, Disappointing Rear Legroom

Our other major complaint centers on the interior, where we encountered the Sierra’s first—and seemingly only—inadequate number. Despite the truck’s 240.1-inch overall length and 78.3-inch height, the back seat of the cab is snug in one key dimension. With legroom not even 1.5 inches greater than that found in the back seat of a Chevy Malibu (39.0 versus 37.6), even shorter staffers found the Sierra’s rear perch lacking. Ford’s F-series Super Duty crew cab offers 3.1 more inches than the Sierra (42.1), and in Mega Cab trim, the HD Ram offers enough interior space for the Detroit Pistons’ starting lineup.

Additionally, although the Denali package spruces up the interior, it doesn’t do anything about the low quality of the plastics. (At $1305 more than a similar Sierra SLT, the main benefit of the Denali package is the monochromatic exterior appearance.) The black tuxedo treatment inside and out masks the cheapness somewhat, but the massive expanse of black plastic that forms the inner door looks low-budget, as does the lower dash panel. Not only that, but the materials feel hard and hollow.