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This season we have been using
a GMC Denali pickup to tow trailers around the country.
This truck revolutionizes towing trailers with its new Quadrasteer
four-wheel steering system. At speeds less than 60 km/hr
the rear wheels of this truck turn the opposite direction
to the front creating a 21% smaller turning circle. Anyone
who has ever tried to do a U-turn with a trailer behind
will certainly appreciate this feature. Above 60 km/hr,
the rear turns the same direction as the front wheels allowing
better lane changes and less sway when towing a trailer.
The electronics that control the rear axle were designed
by Delphi Automotive Systems, a former parts division of
General Motors, that was spun off in 1999.
 A
switch on the dash allows the driver to select normal steering,
four wheel steering, or four-wheel tow steering options.
At low speeds the electronically controlled open-knuckle
Dana 60 axle will turn up to 12 degrees to assist the driver
to turn in ten feet less than a normal truck and the same
circle as a small sport coupe. The 4WS Tow mode reduces
the amount of rear wheel steer at lower speeds and provides
more rear wheel steer at higher speeds to increase towing
stability.
The electronic microprocessor control module is mounted
under the rearmost frame member, where it is protected form
road assaults. The steering angles are controlled by inputs
from a speed sensor, and a steering position sensor that
feeds it data to an electric motor that drives the rear
steering rack through a planetary gear.
To allow more turning clearance for the tires, the composite
rear fenders have been flared and their reinforced reaction
moulded construction also resists dents and corrosion. With
Quadrasteer the Denali gets a new standard 4.10 rear axle
that raises the Combined Weight Rating by 200 pounds to
16,000 pounds and boosts its trailer rating from 8700 pounds
to 10,000 pounds with an equalizing hitch and sway control.
A larger 9.75-inch rear ring gear increases the rear axle
gross weight rating by 250 pounds to 4000 pounds.
 The
325 hp Vortec 6000 engine with 370 pounds-feet of torque
coupled to a 4L65E 4-speed transmission runs on regular
87-octane fuel. The engine block is cast iron with aluminium
heads, overhead valves, coil near plug ignitions system
and platinum-tipped spark plugs with low resistance wires.
The Denali has independent suspension with computer-selected
torsion bar and a 30-mm stabilizer bar. The tires are P265/70R17
Michelin all season steel belted radials. (
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The refined interior features plush tone-on-tone leather
trimmed seats, 10-way power controlled bucket seats with
heated front and second row cushions. A large multifunction
extended console with driver information centre provides
fingertip control for many vehicle functions, and a 6 speaker
Bose Acoustimatic audio system tailored to the cab's unique
acoustical environment will keep you entertained as you
tow your trailer down the road.
The instrument panel features the International Standardization
Organization symbols instead of text. The Denali's instrument
cluster has a unique black background, blue backlighting,
and white pointers. A dual-zone automatic climate control
system controls air delivery, fan speed, air temperature
and recirculating air to provide quick warm-ups and cool-downs
and up to a 30-degree difference in individualized front-seat
comfort. The front driver and passenger seats on the Denali
have independently heated seatbacks and cushions with a
choice of three temperature settings.
The eight-button steering wheel controls that are standard
on Denali provide secondary audio adjustments and permit
calculations for trip and fuel data, and also allow two
drivers to program and personalize up to nine vehicle functions.
With vehicles equipped with OnStar , the buttons can also
initiate voice recognition. The OnStar system now combines
the previous global positioning antenna and the cell phone
antenna in the same unit to give a cleaner look to the roofline.
 The
Denali has a standard AM/FM radio with CD player, cassette
and remote in-dash 6-CD changer. Fully integrated multiplexed
wiring provides additional power for many new features,
improved reliability and diagnostic capability and includes
a 145-amp alternator.
The mirrors on the Denali have large 60 square inch surfaces
that are heated and have turn signals in the glass. The
power adjustable camper mirrors will extend to 106-inch
vehicle width.
Brakes have been improved to provide more stopping power
and less maximum better pedal pressure required for high
deceleration stops, improved ABS performance and additional
alerts to malfunctions and required repairs. The Autotrac
part-time 4WD system provides more fuel-efficient 2WD operation
and improved feel in the Auto mode when turning corners
at low speeds.
Quadrasteer will also be offered as an option on other
GMC Sierra wide side pickups in 2003. (Page
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