What's the big deal about Crab Walk?
The first thing to know is that it's based on a four-wheel steering system, which will be available on higher trim levels of both Hummer EV models. As the name suggests, four-wheel steering allows the rear wheels to turn up to 10 degrees in or out of phase with the front wheels. By default, the rear wheels swivel the opposite way at low speeds, enabling the Hummer to turn tighter — a boon in parking lots, for example. At higher speeds, meanwhile, the rear wheels turn in the same direction as the fronts, making for more stable lane changes.
Now, this is far from new technology. GM was selling trucks and Suburbans more than a decade ago with Quadrasteer four-wheel steering, and cars such as the Audi RS 6 Avant and Porsche 911 use it today to improve overall performance and handling.
No vehicle has used it quite like these Hummer EVs, though.
Specifically, when the driver activates Crab Walk mode, the Hummer will override the default out-of-phase turning at low speeds and instead turn all four wheels in the same direction. That means you can effectively drive diagonally to avoid an obstacle rather than trying a multipoint turn that might not work anyway.
It's an especially intriguing feature when you consider the formidable size of these Hummers. The Hummer EV SUV is more than 16 feet long, while the SUT truck stretches out more than 18 feet. Both are more than 7 feet wide too. That's both longer and wider than a GMC Yukon. In something so large, you're going to want all the help you can get in tight spots. GMC even touts the benefits on public roads in a new video.