Yahoo Autos How GMC Got 11,500 Lb-Ft of Torque From the Electric Hummer
The new GMC Hummer has some mind-boggling specs: The EV pickup truck does 0-60 mph in a claimed three seconds, with three electric motors making 1000 horsepower and, notably, 11,500 lb-ft of torque. That last number is so far beyond the typical passenger-vehicle figure, it's hard to wrap your head around. A brand-new GMC Sierra 2500HD with the Duramax diesel engine makes 910 lb-ft—GMC's specs make it sound like the new Hummer makes more than 12 times as much torque. That's not really the case.
Tesla pulled a similar trick when it revealed the second-generation Roadster in 2017, claiming the sports car made more than 7000 lb-ft of torque. The difference is this: While internal-combustion vehicles are rated on engine torque, an electric vehicle's output is measured in wheel torque, a very different number.
As detailed by Jason Fenske of Engineering Explained, wheel torque is the torque put out by the power source (internal-combustion engine or electric motor) multiplied by the effect of any gear ratio that changes that output on its way to the wheels. This makes sense for EVs, since most of them connect their motors directly to the wheels, no multi-ratio transmission needed. The equation is simply motor torque multiplied by the final drive ratio.
Let's get back to that diesel GMC Sierra 2500HD. It's got a 10-speed transmission, meaning it will have a different maximum wheel torque number for each gear. Let's calculate the wheel torque in first gear: 910 lb-ft x 4.54 (the gear ratio for 1st) x 3.42 (the differential gear ratio). The result? 14,129 lb-ft of wheel torque. Suddenly, the Hummer's 11,500 lb-ft of wheel torque isn't so impressive.
If you want to compare apples to apples, you have to find out the torque of the actual electric motors, a number that GMC did provide: 1000 to 1100 lb-ft. That's still a ton of torque. And because it's an electric motor, that torque will be available in an instant, and it will never be delayed by a gear-shifting transmission, hence that outrageous 3.0-second 0-60 sprint.
So, no, the new Hummer doesn't have 12 times as much torque as a diesel Sierra. We still can't wait to drive it.
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