GMC's 2011 Sierra heavy-duty pickups now have increased towing (21,700 pounds) and payload ratings (6,635 pounds). To accomplish the rise in towing capacity, the engineering team tested the Sierra HD over various terrains, grades and weather conditions.
The pickups also received design and lab analysis as well as climatic wind tunnel testing to confirm stable handling and performance of the powertrain, drivetrain and brake components at maximum gross combined weight rating.
Rick Spina, GM Full-size Truck global vehicle line executive, said that in developing the Sierra HD, it had been focused on providing customers "the most capable heavy-duty trucks in the market" with some premium features and styling.
Spina also revealed that its first set of capability tests confirmed that the team had surpassed the payload and towing targets by a large margin.
Engineers used higher strength steel for the cargo box sills to achieve the increased payload capacity. Extensive testing was done on the vehicles.
To increase the payload capacity of the Sierra HD, the engineering decided to go for higher strength steel as the material for its cargo box sills. To determine the maximum payload, the team conducted a series of tests not just on the cargo box but also on the components of the rear axle.
The results showed that there was a 6,635-pound increase with regards to the maximum payload rating. Spina said that the company is urging its customers to have the Sierra HD undergo a test drive and compare it with other manufacturers.
Due to the testing that was conducted, he added, the company is sure that the Sierra HD will be the better option for real-world towing and hauling needs. The exclusive Denali line will also be offered through the Sierra Denali 2500 and Sierra Denali 3500, a first for GMC.
The difference offered by the Denali variant is that the chrome grill has round air inlets, in addition to the iconic four-bar. It will also have the body color bumpers and the chrome door handles plus chrome highlights.
The aluminum wheels come in three choices: 17-inch, 18-inch, and the 20-inch. The Sierra HD remains to be ahead in its segment as the engine can deliver 397 hp with a maximum torque of 765 lb-ft. In addition to the 6,635 lbs. of maximum payload, it offers 17,000 lbs. of conventional towing and 21,700 lbs. of 5th-wheel towing.
Maximum GCWR is rated to be 29,200 lbs. The Sierra HD will be manufactured at its assembly plant in Flint, Michigan, with production slated to start next week. Customers should expect authorized dealers to feature these heavy-duty trucks soon after that.