Press Release
New Yukon Chassis and Suspension
Yukon and Yukon Denali's chassis and suspension systems have been redesigned for improved ride and handling. The vehicles ride on a 116-inch (2946 mm) wheelbase and feature a fully boxed perimeter-type frame, which provides an extremely solid foundation that contributes to car-like, class-leading smoothness and ride.
The hydroformed frame has three distinct sections bays with specific strength and support characteristics. These bays allowed engineers to maximize each section without compromising other areas. Chassis stiffness is greatly enhanced throughout the frame, as well as providing enhanced performance during a crash. Torsional stiffness (side-to-side) was increased 49 percent and beaming frequency (front-to-back) was increased 35 percent over the previous model. As a result, vehicle load capacity is increased by 5 percent.
The 2007 Yukon models have wider front and rear tracks than previous-generation vehicles. The front track is 68.2 inches (1731.8 mm) vs. 65 inches (1651 mm). The rear track is 67 inches (1701.8 mm) vs. 65.98 inches (1675.8 mm). Yukon 's wider track enhances smoothness and promotes overall vehicle stability, which the driver and passenger can feel through more solid, composed and linear ride and handling characteristics, as well as flatter, more controlled cornering.
New coil-over-shock front suspension
A new coil-over-shock front suspension is used on all models. The coil-over configuration offers smoother, more precise handling characteristics and reduces vibration and harshness, especially with Yukon and Yukon Denali's larger wheel-and-tire combinations.
The new suspension system uses specially tuned coil springs and 46-mm monotube shock absorbers (except Autoride-equipped vehicles), along with steel upper control arms and forged aluminum lower control arms. The aluminum lower arms reduce un-sprung mass by approximately 20 pounds (9 kg).
An enhanced five-link rear suspension is used on all models. It features a more robust rear axle design that offers increased payload capacity. Like the front suspension, the rear suspension uses new, stiffer frame mounts for suspension component attachment, along with variable-rate springs and monotube shock absorbers (except when equipped with Autoride).
The 2007 Yukon is available with distinctly tuned suspension systems, each tuned to the model's wheel and tire combination:
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ZW7 Premium Smooth Ride: standard on 2WD and 4WD models
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Z55 (includes Autoride): standard on Yukon Denali and available on Yukon SLT models
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Z71 Off-road suspension
Available on Yukon SLT models and standard on Yukon Denali, the Autoride suspension system is a segment-exclusive bi-state, real-time damping system that provides an extremely refined ride with greatly reduced body motion. The system consists of a semi-active, two-position damping control system that responds in real time to road and driving conditions, based on body and wheel motion sensors. There are also steering, engine torque, brake and speed sensors. Each corner features independent damping control. Autoride's air-lift/auto-leveling system includes air bags located in the shocks. An integrated air pump automatically adds air to raise and level the vehicle's ride height when carrying passengers or a heavy payload. Conversely, air is bled from the shocks when the payload is removed, returning the vehicle to a level ride height.
New rack-and-pinion steering system
A new hydraulic power-assisted rack-and-pinion steering system is standard on all models. It provides precise steering response with optimized on-center steering feel. Steering ratios have been optimized for easy maneuverability in tight parking situations. Noise and vibration have been substantially reduced.
New four-wheel disc brake system
A larger-capacity, four-wheel disc brake system with a new tie rod-type apply system and new four-channel ABS system are designed to provide the Yukon models with superior stopping capability and the segment's best braking feel. ABS is standard on all models, along with a full-function traction control system (traction control only on 2WD models).
New and improved elements of the brake system include larger-diameter front and rear disc rotors and new, stiffer brake calipers. The front rotors measure 13 inches in diameter (330.2 mm), an increase of 1 inch (25.4 mm) approximately 15 percent larger than the previous-generation design. The front rotors also are thicker with large cooling vents, providing enhanced performance and durability. The cast iron, dual-piston front brake calipers are 50 percent stiffer than before, which reduces the tendency for flexing during hard or prolonged braking. The stiffer calipers, along with dual pistons, contribute to a more direct and stronger brake pedal feel.
Rear brakes feature standard vented discs that measure 13.5 inches (342.9 mm), an increase of 0.5 inch (12.7 mm) approximately 7.5 percent over the previous-generation system. Both the front and rear brakes use new, non-asbestos brake pad linings that can deliver up to 40,000 miles of performance during normal use.
A next-generation Bosch 8.0 ABS system is standard. It has more precise valve control the requires less cycling of fluid from the brake master cylinder, resulting in reduced noise and enhanced braking feel when ABS is activated during a braking event. The new ABS system also is less complex and has reduced mass when compared with the previous system.
Standard StabiliTrak electronic stability control with roll-over mitigation
GM's sophisticated StabiliTrak electronic stability control system is standard on all Yukon and Yukon Denali models. Partnered with the new brake system and four-channel, four-sensor electronic brake controls, the system provides more precise, controlled ABS stops, as well as enhanced traction/yaw stability.
The Stabilitrak system has added software algorithms for the purpose of rollover mitigation. The software algorithms use Stabilitrak sensors to proactively predict vehicle "tip up" on a flat road surface, and applies brake force to the outside front and rear wheels in order to reduce lateral force in the vehicle. This brake force intervention can help reduce the likelihood of a roll-over in certain circumstances including "fish hook" maneuvers that involve sudden and rapid back-and-forth steering.
On 4WD models, StabiliTrak uses brake control to precisely control the speed of each wheel and manage torque across the front and rear axles. On 2WD models, the system precisely controls the speed at each wheel and manages side-to-side torque on the rear differential. Individual brake sensors at each wheel provide instant signals to the control module, enabling it to aggressively adjust brake pressure. However, traction is controlled by transferring torque across the rear axle rather than front and rear axles, as in 4WD models. When the vehicle is on a slippery surface, the traction system increases torque to the rear wheel that has the most traction.
On 2WD and 4WD models, the vehicle brake system provides the torque-biasing to enhance traction and engine management is used, as required, to assist in controlling traction and yaw stability. The Autotrac transfer case's control algorithm has been integrated with the StabiliTrak and ABS systems to provide enhanced vehicle stability by managing the front-to-rear torque distribution.
Autotrac active transfer case
Four-wheel drive models feature the Autotrac active transfer case, which helps keep the vehicle sure-footed in slippery driving conditions. When shifted to the "Auto" mode, Autotrac engages all-wheel drive traction automatically. The vehicle operates in rear-drive mode, but torque is automatically split between the front and rear wheels when the system senses all-wheel-drive traction is needed. The process is smooth, quiet and almost undetectable.
New, segment-leading pre-emptive controls allow the Autotrac system to increase the torque to the front axle on slippery roads prior to an occurrence of slippage. This can increase control because the system "anticipates" slippery conditions, not simply react to them. Autotrac also is integrated with StabiliTrak, which now uses the signal from one of Autotrac's slip-detection sensors to provide another measure of input to the stability control system. This new input allows StabiliTrak to operate more efficiently, with less interference operation.
Larger wheels and tires
Complementing the strong styling of the 2007 Yukon is a range of large, 17-inch standard wheels and tires on Yukon models, 18-inch standard wheels and tires on Yukon Denali and 20-inch wheels and tires available on Yukon and Yukon Denali. Some wheel-and-tire combinations are equipped with new P-metric tires that have a nylon cap ply that enhances strength and durability.
Yukon SLE and SLT models come standard with 17 x 7.5-inch bright-face aluminum wheels, with factory-installed 20 x 8.5-inch polished aluminum wheels available on SLE and SLT (20-inch wheels not available on base trim level). Yukon Denali comes with 18 x 8-inch polished aluminum wheels, with 20 x 8.5-inch chrome aluminum wheels available. The 20-inch wheels feature different styling between Yukon and Yukon Denali models, with the Yukon Denali 20-inch wheels featuring a brilliant chrome aluminum finish. All Yukon and Yukon Denali models come with a full-size spare.
