Michigan - General Motors has taken the industry lead
by offering the Quadrasteer four-wheel-steering system for the
first time in a full-size truck. The innovative system, which
makes driving a truck safer, easier and more convenient, will
debut on the GMC Sierra Denali full-size pickup in the fourth
quarter of 2002.
marks a milestone in full-size truck handling and control.
an electromechanical system that turns the Sierra Denalis
rear wheels (up to 12 degrees) in relation to the front wheels,
resulting in unprecedented low-speed maneuverability and high-speed
is truly a game-changer," said Gary White, vehicle line executive,
GM full-size trucks. "Although four-wheel steering has been
available in cars, this is the first application in trucks, where
the benefits are even more apparent."
offers a choice of three driving modes, and is engaged by controls
conveniently located on the instrument panel:
allows the truck to operate like any two-wheel-steer vehicle.
mode at lower speeds, the rear wheels turn in the opposite direction
of the front wheels, which helps the vehicle make tighter turns,
such as when cornering or slipping into a tight parking space.
Quadrasteer reduces the Sierra Denaliss turning diameter
by 21 percent, from 46.2 ft. to 37.4 ft., which is comparable
to that of a Saturn S-Series coupe (37.1 ft.).
speeds, the rear wheels turn in the same direction as the front
wheels, reducing the vehicles "yaw," or rotational
motion, for dramatically better stability during lane changes
and when being passed by a large truck.
also benefits customers who trailer, enabling the Sierra Denali
to change lanes with more confidence and with hardly any trailer
sway. During low-speed towing maneuvers, such as backing into
a boat launch or parking a camper, four-wheel steering greatly
improves the trailer response to steering input.
Tow" mode reduces the amount of rear-wheel steer at lower
speeds and increases rear wheel steer at higher speeds to provide
even more stability than regular four-wheel steering.
you drive the Quadrasteer Sierra Denali, youre a believer,"
said White. "Combining the trucks 325 horsepower Vortec
6000 V8 and all-wheel drive with the maneuverability and stability
of Quadrasteer delivers simply astounding performance. Four-wheel
steering is one of many innovative technologies and features within
GMs full-size truck portfolio which will provide customers
with real benefits while reinforcing brand equity."
operates by sensing the drivers desired steering input by
way of a steering wheel position sensor. This information is fed
to a microprocessor that determines the appropriate rear-wheel
angles, based on steering input and vehicle speed. The microprocessor
feeds its data to an electric motor which, based on algorithms,
drives the rear steering rack through a planetary gearset.
If a system
failure is detected, Quadrasteers failsafe mechanisms revert
to normal two-wheel steering.
the Sierra Denali gets a new standard 4.10 rear axle ratio which
increases its Gross Combined Weight Rating by 2000 lbs. to 16,000
lbs. and boosts its maximum trailer rating from 8,700 lbs. to
10,000 lbs. A larger 9.75-inch rear ring gear is used to increase
the rear axles gross weight rating by 250 pounds to 4000
lbs. The larger rear axle increases the GVW rating 400 lbs. to
To allow more
turning clearance for the rear tires, the Quadrasteer-equipped
Sierra Denali has flared composite rear fenders that give the
vehicle a brawny, capable look. Their reinforced reaction injection
molded construction also resists dents and corrosion.
Denali also adds new safety features, including standard roof
marker lamps and fender-mounted clearance lamps. Interior box
dimensions remain the same.
will also be offered as a regular production option on other properly
equipped GMC Sierra wideside and Chevy Silverado fleetside pickups
beginning in the first quarter of 2002.