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The chassis of the HUMMER H2 was painstakingly designed and engineered to provide a solid foundation for best-in-class off-road performance, while maintaining a refined, comfortable ride on pavement. Not only was the chassis specially tuned for superior off-road performance, it was designed to optimize the off-road balance between rock crawling and desert racing. Special attention was paid in areas of obstacle clearance, suspension articulation, wheel control and underbody protection.

From the start of development of H2's frame design, all components were packaged flush with or above the frame rails. This provides better protection during underbody impacts. It also allows the vehicle to slide over obstacles more easily on the frame rail or rocker protection-H2 is not as likely as other vehicles to get hung up on any low-hanging components.

H2 was created with a long wheelbase, wide tread and short overhangs to provide superior control for the driver in varying types of road or terrain conditions. The short overhangs provide high approach and departure angles, allowing the H2 to drive right into a hole and out again, for example, without getting hung up in front or rear.

With its standard LT315/70R17 tires and air leveling suspension, the H2 has a 43.6-degree approach angle and 39.7-degree departure angle.

Special underbody protection, including large skid plates, helps define the H2's rugged character and enhance its performance characteristics. A thick (4mm) stamped aluminum front engine shield runs from right beneath the front bumper back to the transmission. It angles prominently up at the front, with the H2 logo pressed into the shield just below the bumper. A one-inch diameter tubular steel, ladder-type shield protects the transmission and the exhaust system's two catalytic converters. It is strong enough, when necessary, to briefly support the load of the vehicle sitting on a rock that it is passing over. A third, high-tensile strength, galvanized steel shield protects the transfer case. It has a special cantilevered design, which allows it to flex or spring back after coming into contact with a rock. The shield is designed so that the weight of the truck can move it up when traveling over a rock. But, once the truck has passed over a rock and the shield has done its job of protecting the transfer case, it springs right back to its previous position.

Unique rocker protectors bolt through the frame. Large, standard, black-painted steel tubes, running along each side of the vehicle, protect its lower body and door panels against rocks and stumps. The high-strength structural pieces bolt right into the frame with heavy brackets and are designed to withstand off-road impacts from beneath or from side angles. The rocker protectors are so strong they can be used to pivot the entire vehicle on a rock. The fuel tank also has its own heavy plastic shield, designed to absorb abrasions and hits that would otherwise contact the tank.

Such protective features greatly enhance the H2's performance capabilities because they allow it go places competitors cannot go.

Also providing superior off-road control is H2's solid rear axle setup. It helps optimize suspension articulation and gross motion control, giving the driver a precise sense of vehicle control in the tightest of situations.


A fully welded ladder-type frame, with a modular, three-piece design that incorporates a number of hydroformed components, provides outstanding strength, stiffness and dimensional accuracy for H2's chassis. The hydroformed front section helps create the H2's high approach angle. To improve the frontal crush zone, GM engineers added reinforcements in key box sections of the frame, enhancing its ability to absorb energy, crush and collapse.

Uncommonly flat crossmembers are used around the transmission mounting area to preclude any possible hang-up points. The tolerances for powertrain mount positions have also been tightened to reduce potential noise, vibration and harshness (NVH).

Because of H2's full-time 4WD system, GM engineers also took great care to minimize the NVH transmitted by the front axle to the frame, devising a special three-point mounting system to isolate it. Two forward mounts vertically connect the axle to the frame, while the rear mount attaches it to a crossmember that fits between the two lower control arm brackets in the frame.

The front frame section incorporates a GM-first standard winch receiver. It is designed to handle an impressive 9,000-pound capacity winch for freeing a vehicle that's helplessly grounded. An extension for the receiver could also be used for adding such accessories as a bicycle rack. The receiver itself has the same diameter as the standard integrated rear trailer hitch receiver. Therefore, the front receiver could also be fitted with a hitch that would allow pushing a boat into the water, for example. The winch platform, including the receiver and a bracket, is built right into a thick front crossmember as an integral part of the vehicle's design. Paired tow loops up front complement the distinctive HUMMER-style rear pivoting tow loops.

The mid-frame has a stamped-steel box section design, with common inner and outer sections and a clamshell-welded configuration. Its strength and stiffness help minimize ride and body vibrations, contributing to a smooth ride on-road and providing the strength and stiffness required to handle severe bumps and jolts. As in other GM SUVs, the composite fuel tank (with large, 33-gallon capacity) is mounted inside the left frame rail, ahead of the rear axle, for maximum protection.

The hydroformed, short rear-frame section helps create a high departure angle. It is heavily reinforced in key areas for H2's 8,600-pound GVWR capacity. The rear section incorporates a standard, integral trailer hitch receiver. Unlike with most SUVs (whose hitch receiver is added on), the H2's is built right into the last crossmember of the frame rail and developed into the bumper. A Class 3 trailer hitch is standard.


The H2's standard independent front torsion bar and five-link coil spring rear suspension provides excellent on-pavement ride comfort and control and a high degree of strength, control and rear-axle articulation off-road. An optional self-leveling air spring suspension for the rear takes comfort, control and off-road axle articulation to an even higher level.


The independent front torsion bar has 46mm monotube gas-charged shock absorbers, a large 35.9mm diameter tubular front stabilizer bar and unique tuning. The axle has a 4,000-pound capacity.

The front shocks contain unique features for off-road performance. They have a large, high-strength 40mm center tube and a secondary integral bump stop feature, which allows them to absorb jolts at two junctures. Full-size trucks typically have only one urethane front jounce bumper. When severe bumps push the suspension toward the frame, it acts like a final cushion to protect the suspension from hitting the frame. The H2 also has a secondary jounce bumper built into the shock. So, rather than taking all the load at the bump stop attached to the frame rail, it takes some of the load with the shock's built-in bump stop, slowing the suspension's travel before it hits its final cushion. The design is ideal for absorbing the extreme forces exerted on the jounce bumper during high-speed desert racing.


There are two suspensions available for the rear: a standard five-link trailing arm coil spring suspension and optional self-leveling air spring suspension, available with the off-road package. The package also includes an air compressor and tire inflation accessory.

The standard five-link coil spring suspension's basic linkages include two forged-steel upper control arms and two stamped-steel lower control arms with bushings on each side for better isolation. These components control the solid rear axle's fore-aft and vertical position; a track bar controls the axle's lateral position. This suspension is inherently much smoother than a leaf-spring system. H2's suspension also features brand new variable-rate coil springs, longer shock absorbers and different linkage positioning-all designed to provide more articulation for the rear axle during off-road operation.

The new variable-rate coil springs have a dual stage design for on-/off-road comfort and increased suspension articulation under demanding off-road conditions. On-road (or under lightly loaded conditions), their low or soft spring rate optimizes comfort. Off-road, the springs adjust themselves to varying road conditions. If a driver starts running through undulating terrain or speeding over rocks, the spring rate will progressively stiffen to help prevent high input forces at the rear from being transmitted to body and to keep the suspension from bottoming out. The springs actually progress from a low rate to a transitional and then a high rate. Aside from their excellent ride characteristics, they also provide good handling because, due to their progressive nature, they don't transfer weight to the same degree as conventional coil springs, thereby minimizing vehicle roll.

A specifically tuned, 30mm diameter rear stabilizer bar helps enhance off-road control. It has a tubular design, with a 5mm wall thickness, designed to provide high strength in a lightweight design. Like the stabilizer bar used with the air spring suspension, it is also specially contoured to help protect the more delicate drop links.

The optional, self-leveling air spring suspension system is brand new for GM. The system is available with the off-road suspension package. Targeted to dedicated off-road enthusiasts, it includes a high-capacity air compressor and inflation accessory. Rim protection, a reinforcement of the tire design that extends the durable rubber over the rim of the wheel, and triple sidewalls are standard as well. Rim protection adds extra protection to the tires and prevents them from slipping off the wheels when aired down.

The air spring suspension system's numerous benefits include:

· A smooth on-road ride. The air springs provide a 4.3-Hz rating (natural frequency), compared to the 4.5-Hz rating of the standard coil spring suspension.

· A longer suspension stroke for off-road operation. Longer, 719mm length shocks are used to provide an additional 20mm of rebound travel over that of the coil spring suspension. This improves traction by helping to maintain wheel contact with the ground over undulating terrain. The shock absorbers, although having the same 46mm diameter as those with the coil spring suspension, also feature a larger-diameter-size rod for increased durability.

· Automatic load leveling. If a customer loads up the rear of an H2, for example, the automatic load leveling suspension system will detect the drop in ride height and pump more air into the springs to restore a level condition. It has height sensors attached to the suspension links, which monitor and determine deviations from the standard height, and the system adjusts accordingly. The system includes an air dryer, which removes all the moisture from the air to prevent it from contaminating or degrading the springs. Because it's a closed system, once the springs are charged, they won't lose pressure.

· A driver-selectable rear suspension height elevation ("extended ride height") provides extra ground clearance at the rear and improves the vehicle's departure angle. Off-road, if the truck is in the "4 LO" transfer case mode, the driver can raise the rear suspension by 50mm (about two inches) using a ride height switch on the instrument panel. This increases the H2's rear departure angle from 35.9 degrees to 41 degrees. Once the vehicle's wheels are freed and driver leaves the rock, the system can be returned back to normal. Anytime the vehicle exceeds 20 mph, the system automatically restores the rear suspension to its standard height. Also, at freeway speeds (beginning around 50 mph), it will lower the rear end slightly to further improve the vehicle's stability.