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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.
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| Trailer
towing becomes much easier with Quadrasteer engaged. The Sierra Denali's
pivot point shifts from the front to the rear wheels providing more
maneuverability |
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.
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| The
Sierra Denali sports new roof mounted marker lights and flared rear
shoulders. Note the angled rear wheel in this shot. |
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.
There was
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
trucks.
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