2024 GMC Hummer EV SUV Tech Highlights: CrabWalk, “Fantasy” Sound Effect, and More!

Want to know more about the 2024 GMC Hummer EV SUV? Read all aboutits trim nuances,charging capabilities, and more!

On the occasion of the 2024 GMC Hummer EV SUV's launch, the brand has seen fit to divulge several new technical highlights of this two-box variant of General Motors' new Ultium electric platform—several of which will also pertain to the 2022 GMC Hummer EV truck version (which so far practically nobody is calling "SUT," as they did with its Hummer H2 and H3 predecessor pickups). Let's jump right in.

That 11,500-LB-FT Torque Spec Should Really Be 1,045

The only way a figure like 11,500 lb-ft of torque could possibly make mathematical sense with a horsepower figure of 1,000—even if you're dividing each by four—is if the motors in question were mounted inside the wheels, where they'd never exceed about 1,000 rpm. So, ever since we learned the 2022 GMC Hummer EV's motors would be mounted inboard on the chassis, we knew the five-digit torque number had to be a summation of wheel-torque figures. Since it cannot represent the total torque at the motor shafts, it is not comparable with any other torque spec you read about fromMotorTrendor anyplace else.

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We got chief engineer Al Oppenheiser to spill the beans on the electric motors and the direct-drive ratios they'll use to drive the wheels on the 3X and Edition 1 Hummer EV models that launch first. The single motor driving the front axle spins 13:1 gearing. The two motors individually spinning each rear wheel get slightly taller 10:1 gearing. Presuming ideal traction conditions where equivalent electrical energy can be sent to all three motors, a peak combined shaft torque just exceeding 1,045 lb-ft will multiply out to 11,500 lb-ft at the wheels. Dividing that by three yields just a bit more than 348 lb-ft per motor.

But you can expect GMC to stand by its big number. Engaging "Watts to Freedom" mode will bring up an instantaneous torque gauge, and we hear "it goes to 11" (thousand pound-feet).

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Same Motors, Same Torque, Why Different Power Ratings?

Why does the 2022 GMC Hummer EV pickup truck get a peak power rating of 1,000 hp while the 2024 GMC Hummer EV SUV must make do with just 830? Both GMC Hummer EV variants will use the most powerful of the Ultium lineup's first three motors, which get nominal power ratings of 70, 180, and 255 kilowatts (94, 241, 342 hp). The big one is codenamed X80 (though Oppenheiser says when they gang two of them together on the rear axle, the unit gets an X79 moniker). That 255-kW rating equates to 342 hp (and if our calculations above are right, 348 lb-ft), so why doesn't either three-motor Hummer EV make 1,026 hp?

As you may recall, most electric motors generate peak torque at 0 rpm, and maintain that torque over some range of rpm, before tapering down. Horsepower is simply torque times rpm/5,252. In an electric motor, the rate at which rpm (and hence power) increases and torque decreases is governed by how fast electricity gets delivered to the motors. This is how Tesla has been able to "download" more horsepower to its vehicles, by sending new code that instructs the power inverter to send more electrons more quickly. For the new GMC Hummer EVs, differences in battery pack voltage levels between the truck and SUV are responsible for the power difference, because ...

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Shorter Wheelbase=Lower Power

The pickup truck's 135.6-inch wheelbase accommodates 24 battery modules, mounted in six rows, each two abreast and two deep. The SUV's 126.7-inch wheelbase requires a shorter battery pack that only has room for five rows of battery modules. The 20-module pack operates at a slightly lower voltage, and hence is unable to supply electrons to the motors at the same rate as the larger pickup truck's 24-module battery can. This is also the primary reason why the SUV's 300-mile estimated range falls 50 miles short of the pickup truck's.

Crab Walk Mode!

We've known this was coming, and we've seen the 2022 Hummer EV pickup crab-walk around obstacles (you can, too, in the video above). Now we know how to activate it: Press the mode switch (located at the 9 o'clock position on the terrain-mode dial) for five seconds, until a "Welcome to Crab Walk Mode" splash screen comes up on the instrument cluster. Now when you turn the steering wheel, the front and rear wheels steer in unison up to 10 degrees. Continue turning it and the front wheels will turn more (though this would only result in a gigantic turning circle). It works in forward or reverse, but as you accelerate, the rear wheels automatically straighten themselves out between 25-35 mph. Conceived as an off-road obstacle avoidance feature, it may also prove convenient for parallel parking and other on-road maneuvers.

Non-Crabby Rear-Wheel Steering Tricks

As in most vehicles with four-wheel steering, at low speeds the rear wheels generally steer opposite the fronts. This tightens the 2024 Hummer EV SUV's curb-to-curb turning-circle diameter by 6.5 feet, from 41.9 to 35.4 feet—same as a Bolt EV. At higher speeds, the rear wheels steer in the same direction as the fronts to smooth out lane-changes. So, when Super Cruise automatically executes a lane change, the Hummer EV will "crab walk" from one lane to the other so you don't perceive any turning sensation.

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Bi-Directional Charging

The energy in a new GMC Hummer EV will be useful not only for on and off-road transportation, but also in case of a home power outage, to power a camping trailer, or to recharge a fellow EV traveler, on-road or off. Accessory cables that attach to the standard EV charge port will be capable of exporting 3 kW of 110-volt power to your home or camper, or up to 6 kW of 240-volt power. This feature will come standard on all but the base model. Speaking of that charge port, it's located at the far rear of the driver side because most DC fast-charge cables are comparatively short, and this puts the port within easy reach when backed into the charging spot. Oh, and a 19.2-kW onboard AC charging option is available on upper trim models—useful for those whose garage has a 100-amp circuit-breaker and 4-gauge garage wiring capable of flowing 80 amps to their level-2 charger.

Aluminum in the Battery

Just as a refresher, the GMC Hummer EV's Ultium battery features NMCA chemistry. That stands for nickel-cobalt-manganese-aluminum, which are the metals comprising the cathode. These metals host the lithium ions when the battery is in its discharged state. This battery chemistry is key to meeting the cost and range targets, because the presence of aluminum permits a higher nickel content and crucially reduces the cobalt content. Cobalt is the rarest, priciest, and most difficult to source ethically. A Hummer EV battery cell reportedly requires 70% less cobalt than a cell in the Bolt EV.

Formula E Jet Fantasy Soundtrack

And finally, you may know electric vehicles are required to make artificial noise below 25 mph to warn vision-impaired people they're coming. (The noise also benefits people who just aren't paying attention to their surroundings.) We can't wait to hear the 2022 and 2024 Hummer EVs' final sound signature, which Oppenheiser tells us was inspired in part by Formula E racing sounds, jet engines, and guitar riffs from Aldo Nova's "Fantasy." Rock on, Hummer.