GMC Sierra All Terrain HD concept takes heavy-duty capability to new ground

GMC has introduced the GMC Sierra All Terrain HD concept at this year’s 2011 North American International Auto Show, the auto industry’s premier global exhibition held in Detroit, Michigan between 10^th and 23^rd of January and featuring some of the markets’ most groundbreaking vehicles worldwide.  In keeping with the event’s prolific status, the Sierra All Terrain HD concept, a vehicle that commands attention, made its debut to the international community.  The vehicle is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain suspension and premium details expected of a GMC – all designed to enable greater access to off-road destinations.

“The Sierra All Terrain HD concept takes GMC’s outstanding new HD platform to the next level, marries it to the legendary Duramax diesel/Allison transmission, and provides a heavy-duty expression of GMC’s premium All Terrain package,” said Lisa Hutchinson, GMC product marketing director. “It delivers the exceptional capabilities of the Sierra HD – hauling, towing and performance – and applies them to the toughest driving environments.”

The Sierra All Terrain HD features a unique Crew Cab/short box body configuration that supports a wheels-at-the-corners proportion. Shorter in overall length than production Sierra HD models, the concept’s dimensions contribute to greater approach/departure angles.

Purposeful design

From every angle, the All Terrain HD looks the part of a dedicated off-road performer, with bold, accentuated features complemented by a wide stance and tall profile. 

Streamlined bumpers are designed to enhance approach/departure angles and incorporate frame-mounted recovery hooks – with integrated skid plates. A large, airflow-optimized grille maximizes cooling in tough conditions, while a forced-induction hood delivers more air to the engine.

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. 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.

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.

All Terrain 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 track that enhances stability during off-road and highway driving.

An increased ride height provides greater ground clearance, while specialized Fox off-road shocks deliver exceptional damping on tough terrain. They were created especially for the All Terrain HD, with specific valving.

Powertrain details

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 and 1,037 Nm of torque.

The powertrain’s efficiency is assisted by the Allison 1000 transmission and 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 1,225 kg

- Estimated conventional towing capacity of 5,896 kg

- Estimated fifth-wheel towing capacity of 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 off-roader.