The addition of Quadrasteer has required some exterior changes to the Denali further setting it apart from the C3 and adding more testosterone to the truck. The first things you notice are the muscular, composite shoulders added over the rear wheels to accommodate the wider rear axle and turning requirements. Overall body width has grown from 78.5-inches to 83.5-inches. Government regulations stipulate the trucks over 80-inches in width also include roof mounted marker lamps and fender mounted clearance lights so the Denali looks almost like an athletic dually at first glance.
We took the Sierra Denali out first-hand to test drive the Quadrasteer's towing and trailer-free capabilities.
The first Sierra Denali we drove came with a 30-foot, 7500 pound trailer attached for a GCWR of 14500 pounds.
GMC engineer Gene Rodden took us out to a closed course, marked with cones, to test out Quadrasteer's maneuverability. Attempting to tow in 2WS mode quickly demonstrated how challenging towing can be and the large amount of attentiveness required by the driver to clearances, the length of both vehicles and placement of the trailer axle. Needless to say the course was not optimized for 2WS trailer towing resulting in the senseless mutilation of multiple orange traffic cones.
Switching to 4WS TOW mode to run the same course again, Quadrasteer provided a clear improvement in maneuverability, measurably improving the driver's level of confidence and margin of error in moving the trailer around and meeting clearances in corners. The cones were also a lot happier.
An interesting demonstration of rear wheel movement was shown in response to increased throttle while holding the brake on. Quadrasteer is also sensitive to throttle response not steering alone. 4WS TOW angles ranged from 7 degrees, increasing to 12 with full lock for low speed maneuvers. Reversing the truck lowered the tolerances and reduced the steering angles available for maneuvering the truck. Not that it was a rally course, but rounding the cones at a decent clip seemed to make trailering easier than maneuvering at very low speeds.
We left the trailer course to make our way to Highway 52 outside San Diego.
Navigating surface streets with the trailer and heavy morning commuter traffic proved to be quite easy with Quadrasteer. When making right turns you could actually keep the Denali in the right lane of the street you had just turned onto. No more wide turns into the middle or left lanes. And when making U-turns the only word that came to mind is amazing. We made a U-turn onto a three lane road and were easily able to make the middle lane towing the 30-foot trailer!
On the freeway Quadrasteer shined again. Lane changes at 60 mph were seamless. The synchronized movement of the front and rear wheels at these speeds reduced the articulation angle between the Sierra and trailer. Reduced side forces acting on the trailer made the entire platform more stable.
If you didn't know you were towing a trailer and looked in the rearview mirror, you would think someone was tailgating.
Rodden remarked that during separate road testing on highways in high wind conditions in 4WS TOW mode the truck / trailer combo was also much more stable than in standard 2WS mode.
The second Sierra Denali we drove was unloaded. Like last year's 2001 Sierra C3 we drove the Denali displayed the same great on-road driving characteristics.
As the only currently produced all-wheel drive pickup, Quadrasteer enhances the driving experience so you feel like you are driving a luxury sport sedan, albeit a very tall one. On twisty mountain roads the truck was outstanding.
no mention of pricing for the 2002 Sierra Denali, but we expect the truck
to come in somewhere just north of $40,000. That's a hefty price tag for
an extended cab truck. Clearly this is a truck for early adopters but
we do expect Quadrasteer to quickly appear on other, less expensive, GM