Large fender flares stretch away from the body to cover the 35-inch-tall
BFGoodrich tires. At the rear, the cargo box features lockable, lighted storage
compartments, along with a number of tie-down cleats, including a pair in the
bed floor and two on each side of the bed. A non-slip rubber pad is used on the
tailgate, while two special compartments inside the cargo box provide access to
a 110-volt power outlet and air compressor. A composite bed liner with a unique
"circuit board" pattern provides a protective cover for the bed.
Motorized, deployable assist steps for the cab and cargo bed make it easier to
enter and exit the All Terrain HD, while maximizing ground clearance during
off-road driving. It also incorporates a number of industrial-grade lighting
elements to provide greater visibility for safer driving where stars may be the
only other source of illumination. The lighting details include:
- High-intensity LED headlamp, taillamp and fog lamp lighting mounted in
impact-resistant composite housings and featuring edge-lit illumination
- High-intensity LED park and turn signal lamps
- Smooth-appearance front marker lamps integrated behind the top edge of
the windshield glass
- Integrated center high-mounted stop lamp and rear marker lights mounted
at the top edge of the rear window glass
- LED floodlights for the cargo bed and assist steps.
The All Terrain HD is painted Iridium Metallic - a dark charcoal color that
reveals a reddish, anodized inflection when viewed from certain angles. It
complements other anodized and satin-metal finishes on the exterior, which give
the truck a more precise and functional appearance.
The interior matches
the exterior aesthetic, with premium appointments and increased functionality,
including enhanced lighting. It conveys solidity and precision, blending accent
details such as stainless steel mesh and satin chrome with an amplified
expression of the All Terrain's premium features. Two-tone dark gray leather
seats, matched with embossed carbon fiber-style leather on the seating surfaces,
have red contrast stitching. Additional leather-wrapped interior features
include the steering wheel, instrument panel and center console.
navigation radio is also featured on the Sierra All Terrain HD concept and
previews future radios to be offered in GMC vehicles. An integrated 80-gig hard
drive contains map data for the navigation system. It eliminates the need for a
map disc and provides greater storage of music from portable devices. It also
features DVR-style "time lapse playback," which allows up to 20 minutes of
recording/playback from the AM/FM/XM radio stations.
Chassis and Suspension
Based on the chassis of the 2011 Sierra HD
trucks, the All Terrain HD features a fully boxed steel frame with exceptional
strength and torsional stiffness. It incorporates the production models' new
independent front suspension and asymmetrical rear leaf-spring suspensions, but
with a wider 73-inch (1,853 mm) track (front and rear) that enhances stability
during off-road and highway driving. A production Sierra 2500HD has front and
rear tracks of 68.8 inches (1,748 mm) and 67.3 inches (1,709 mm), respectively.
An increased ride height provides greater ground clearance of 21.1 inches
(536 mm) at the rockers and 11.8 inches (300 mm) at the skid plates, while
specialized Fox off-road shocks deliver exceptional damping on tough terrain.
They were created specially for the All Terrain HD, with specific valving. The
shocks feature visible, remote fluid reservoirs - connected to the shock bodies
via custom hoses - mounted in the wheel house liners and are matched with front
and rear jounce shocks. They add additional compression damping and more
controlled rebound, which helps increase control, stability and handling.
The All Terrain HD also features electronic disconnection of the front
stabilizer bar, which enables greater crawling capability on rocky terrain. The
driver simply pushes a button inside the cab to disconnect it from the front
Custom upper and lower control arms for the front suspension
are designed to work with the Fox off-road shocks and jounce shocks, while
supporting the greater ground clearance and ride height. They contribute to the
wider track, as do the aggressive 20-inch machined aluminum all-terrain wheels.
The wheels are deep, with six split-spoke elements, and are constructed in a
reverse drop-flange method that ensures optimal strength. They also feature a
mix of satin chrome and anodized aluminum finishes, which provide durability and
a premium appearance that complements the body's Iridium Metallic color.
A full composite underbody protection system shields the All Terrain HD's
transmission, drivetrain, fuel tank, exhaust system and axle differentials. It
starts with the front bumper, which rolls beneath the truck and leads to a
composite, integral belly pan that covers a front suspension skid plate.
Protective covers are also mounted beneath the driveline components, while the
front and rear differentials feature direct-mounted skid plates. The rear bumper
is integrated with the rear skid plate.
The Sierra All Terrain HD concept is propelled by the new, production 6.6L
Duramax turbo-diesel V-8 and Allison 1000 six-speed automatic transmission
powertrain combination offered in the 2011 Sierra HD trucks. The Duramax is
rated at 397 horsepower (296 kW) and 765 lb.-ft. of torque (1,037 Nm).
The powerful 6.6L Duramax is more fuel-efficient - with up to 11-percent greater
fuel economy than previous versions - and reduces NOx emissions by up to 63
percent. The powertrain's efficiency is assisted by the Allison 1000
transmission, which requires less engine power to funnel torque to the axles. It
also incorporates a "smart" exhaust brake feature that helps save wear on the
brakes on downhill grades, a feature available on production Sierra HDs.
With the same proven powertrain as production Sierra HD trucks, the All Terrain
HD delivers comparable hauling and towing capabilities, including:
- Estimated payload capacity of 2,700 pounds (1,225 kg)
- Estimated conventional towing capacity of 13,000 pounds (5,896 kg)
- Estimated fifth-wheel towing capacity of 15,600 pounds (7,076 kg).
The Sierra All Terrain HD also features four-wheel drive, with automatic
locking front and rear differentials, while the 14-inch, four-wheel disc brake
system from the production Sierra HD provides the stopping power for this unique
GMC Sierra All Terrain HD Concept: Photo Gallery, Review (1/2) and Specifications