What does it mean to have a fully boxed, high-strength steel frame? It means that the backbone of our Heavy Duty lineup is more rigid, more durable and stronger where it counts most. This allows better suspension tuning as well as better ride quality. We've increased the frame strength more than 90% and torsional stiffness by a factor of five. Closed sections (boxed frames) provide stronger crossmember mounting as well, for improved frame durability at critical joints.

When it comes down to it, you buy a Heavy Duty pickup to haul or trailer a lot of weight.

Our HD trucks offer:

• Max. 13,000 lbs. conventional trailering capacity1
• Max. 15,600 lbs. 5th wheel trailering capacity1
• Max. 2,959 lbs. payload capacity2

1 Maximum trailer ratings are calculated assuming standard equipped vehicle, driver and required trailering equipment. The weight of optional equipment, passengers and cargo will reduce the maximum trailer weight your vehicle can tow. 10 to 15% of the trailer weight is the recommended trailer tongue load.

2 Maximum payload capacity includes weight of driver, passengers, optional equipment and cargo.

If you are looking for distinctive styling, premium features AND Heavy Duty capability? You're in the right place. The Denali HD gives you the distinctive Denali grill and interior, brushed metal accents, 12-way power seats, Bose premium surround system and more.
But that's just on the surface, the 2500HD crew cab is available in 4WD with either the 6.0L gas or Duramax 6.6l diesel engine and delivers some serious capability:

• GVW (Gross Vehicle Weight)1 up to 10,000 lbs
• Max payload2 up to 2,959 lbs
• Conventional trailering3 up to 13,000 lbs
• Fifth-wheel trailering3 up to 15,600 lbs
• GCWR (Gross Axle Weight Rating)4 up to 24,500 lbs

1 When properly equipped; includes weight of vehicle, passengers, cargo and equipment.

2 Maximum payload capacity includes weight of driver, passengers, optional equipment and cargo.

3 Maximum trailer ratings are calculated assuming standard equipped vehicle, driver and required trailering equipment. The weight of optional equipment, passengers and cargo will reduce the maximum trailer weight your vehicle can tow. 10 to 15% of the trailer weight is the recommended trailer tongue load.

4 When properly equipped; includes weight of vehicle and trailer combination, including the weight of the driver, passengers, fuel, optional equipment and cargo in the vehicle and trailer.

With larger, stronger parts in our new front suspension, we've made it more capable and durable than anything we've offered before on a Sierra Heavy Duty truck. That's part of the story behind Sierra HD now offering the highest GCWR in this class of truck. That's also why our Front Gross Axle Weight Ratings increased by 25%, to 6,000 lbs., on select 4WD models equipped with the Snow Plow Prep Package. Our independent front suspension delivers this capability and provides optimal ride and handling. You'll enjoy great road isolation and better tire-to-ground contact than is possible with a solid axle suspension. Our dual jounce bumpers provide multiple paths to handle the increase in loads going through the frame and lower control arms. So, next time you bump into one of those "solid front axle is the only way to go" guys, remind them that your truck can do all that theirs can do without the teeth-rattling ride.

When you increase payload and trailer ratings as much as we have, you need to engineer the suspension to bear much of the load, without compromising on ride quality. Our new rear suspension includes asymmetrical leaf springs that increase 20% in size. This spring design (shorter in the front than in the rear) reduces 'hop and shudder' and includes larger fasteners to handle the increased loads. Urethane jounce bumpers improve energy management. The result: improved capability and ride quality.

By turning just two bolts, you can adjust the trim height of the front suspension to allow the vehicle to sit at a normal attitude even when fully loaded to the Front Axle Weight Rating. When the truck's stance is leveled, it reduces tire wear, manages energy better and gives you a better running clearance when plowing. And when the equipment is removed, the truck can be easily adjusted back to a nominal position.

The 2011 Sierra Heavy Duties include an array of features to help you control the loads you ask it to bear, especially when trailering. Standard on all Single Rear Wheel Sierra HD models the Trailer Sway Control works directly with StabiliTrak to identify if your trailer is swaying and uses the power of the engine as well as the braking systems on the Sierra HD and the trailer, if equipped, to bring both the vehicle and trailer under control

Mounted on the dash, and available on all models, the Integrated Trailer Brake Controller provides a measured brake force signal to electric–controlled trailer brakes. Not only is it an important safety feature, but it eliminates the need for an aftermarket device.

The braking system plays an integral role in many of the control systems in the Sierra HD. Everything from Trailer Sway Control, StabiliTrak, and Intelligent Brake Assist to Standard Hill Start, all rely on braking. So we increased the rotor diameter nearly 10% to 14". You'll notice improved pedal feel and shorter pedal travel.

Our "smart" system1 varies the amount of negative torque needed based on the truck load and grade. The exhaust brake also helps reduce brake fade, prolongs brake life and will provide you with plenty of confidence when hauling heavy loads on downhill grades.

1 Requires Duramax 6.6L Turbo Diesel V8 engine.

Using the engine and transmission to your advantage, Automatic Grade Braking helps slow the Sierra HD on downhill grades. Its gives you more control and helps reduce brake wear.

With all the trailering innovations we've added to the Sierra HD, it made sense to maximize the first point of contact, the trailer hitch. So we redesigned the trailer hitch and gave it a max Trailer Weight Rating of 16,000 lbs.1

1 Maximum trailer ratings are calculated assuming standard equipped vehicle, driver and required trailering equipment. The weight of optional equipment, passengers and cargo will reduce the maximum trailer weight your vehicle can tow. 10 to 15% of the trailer weight is the recommended trailer tongue load.

Standard on all Single Rear Wheel Sierra HD models, this feature uses the vehicle and trailer brakes (if equipped) to keep your vehicle and trailer from rolling backwards when launching on an incline. The brakes apply for approximately 1.5 seconds, allowing you to move your foot from the brake pedal to the accelerator pedal without vehicle movement.

With improvements ranging from software updates on the Allison transmission to lower idle speeds, to improved aerodynamics and an increase in the size of our fuel tank, we've engineered every feature to deliver a more efficient Sierra HD. And it shows, based on GM testing, the Duramax Diesel can provide a highway mileage range up to 680 miles on a single tank of fuel.1

1 Based on GM testing

The 36-gallon fuel tank helps keep you and your Sierra HD on the road. With a 38% increase in tank capacity over the 2010 Sierra HD standard box, you'll notice a real difference every time you pass the pump.

The available Duramax Diesel is a force to be reckoned with. It's more powerful, quieter, more efficient and has 397 horsepower and 765 lb. ft. of torque.1 There's nothing you can throw at this engine that it can't handle and you'll have plenty of time to try. Teamed with the Allison transmission, this powertrain has a strong reputation and proven track record, with nearly 1.3 million sold in the last decade.2 It's one powerful combination. It is also B5-B20 biodiesel compatible.

The 2011 Sierra HD's new Duramax uses sophisticated technology that makes it the cleanest Duramax ever built. Learn more about Diesel Exhaust Fluid (DEF).

1 397hp @ 3,000 rpm, 765lb.ft. torque @ 1,600 rpm

2 Based on GM sales data

We've beefed up the Allison Transmission in the 2011 Sierra HD to handle the increased output of the Duramax. We've increased the output shaft diameter and clutch capacities and beefed up the torque converter housing. We've improved the transmission our customers depend on to get the truly heavy work done. And that's saying something considering it's an Allison that drives the M1 tank.