Why The Hummer EV's 11,500lb ft Figure Is Hugely Misleading, And How Much Torque It Really Makes

GMC has confirmed its claimed '11,500lb ft' isn't measured in the usual way - here's Engineering Explained crunching the numbers to find out a more useful torque figure
Why The Hummer EV's 11,500lb ft Figure Is Hugely Misleading, And How Much Torque It Really Makes

The new GMC Hummer EV‘s absurd-sounding 11,500lb ft peak torque figure sounds like a typo, but it is indeed accurate. However, the widely-quoted number is extremely misleading, as Jason Fenske/Engineering Explained will tell you.

Although it isn’t mentioned in the press release for the vehicle’s full reveal nor the teaser sent out earlier this year, GMC admitted to YouTube’s favourite whiteboard enthusiast that this estimate is based on wheel torque. This number is engine torque (which is what manufacturers will usually quote) multiplied by transmission.

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Since that throws a huge variable into the mix, there’s little point in quoting wheel torque. Unless, of course, you’re hoping people will repeat this headline-grabbing but largely meaningless number without explaining what it truly means.

Its use is “deceiving without context,” Fenske says, and we won’t disagree. It’s worth pointing out, though, that GMC isn’t alone in doing this - a few years ago Tesla said its new Roadster develops 10,000Nm (over 7000lb ft), but again, wheel torque was being referred to. Indeed at the time, Engineering Explained revealed a video explaining exactly how wheel torque is calculated and why paying any attention to it is largely pointless.

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Although GMC hasn’t provided the ‘proper’ torque figure produced by the Hummer’s triple-motor powertrain, the firm did give Jason the gear ratios for the front and rear axles, making it possible to calculate one. The maths happens above just after the 8min 40sec mark, but it’s worth watching the whole thing since it’s probably the most technically-detailed Hummer video out there.

What we end up with is a figure of around 1000lb ft. Ironically, that’s an extremely impressive figure you’d think GMC would be proud to quote rather than engaging in misleading wheel torque shenanigans.


V-Tech and EcoBoost kicked in yo

I think the reason that this rating was given, aside from marketing hype, is that EV’s like the Roadster and the Hummer are single speed. Any sports car with at least 300 HP will probably make a wheel torque in the thousands of Nm in first gear. However, that first gear is usually limited to about 30 MPH /50 KPH. For a single speed EV, that “first gear” is the gear used all the way to top speed. Of course, they won’t be making that same torque value up to top speed due to the horsepower torque equation, but the fact that it is single speed is one thing to consider.

10/24/2020 - 09:22 |
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