Meet the Father of the GMC Hummer EV’s CrabWalk

Mike Colville has built a dozen off-roading competition rigs in his garage and brought his racing experience to GMC.

byKristin V. Shaw|
GMC News photo


Mike Colville may be the senior manager for complex feature integration for GMC, but in his spare time he’s a straight-up gearhead. He’s also a competitive off-road racer and has created more than a dozen custom vehicles from home. That includes the Ginger Chicken, his 4500-pound behemoth build that ran with a 700-horsepower V8 and four-wheel drive, which Colville raced for two years at the hardcore King of the Hammers.

Colville brought his vast knowledge and enthusiasm to the GMC Hummer EV; he has been on the project since Day One back in 2019. And now, all roads to the new Hummer EV's CrabWalk lead back to Colville and what he calls "an army" of team members to accomplish it. 

Mike Colville

Even before he started working on the fast-tracked all-electric truck, he had experience with rock crawlers that use both front and rear steering from his experiments building off-road vehicles. Four-wheel driving is common for people in the rock crawling world; they duplicate the front suspension on the back end. While four-wheel steering isn’t new technology, the application in the form of the CrabWalk is original. Colville recognized that the new Hummer had the potential to utilize that same concept to scoot through tight turns. Eventually, that feature became the CrabWalk.

The CrabWalk is mind-blowing in person, evoking the image of a hippo dancing on its tiptoes. Using four-wheel steering to move in a diagonal direction, the Hummer EV can adapt to sharp turns that might be otherwise damaging or potentially dangerous. In Terrain mode, the rear wheels match the steering angle up to 10 degrees at low speeds, allowing the driver to scuttle around an object like its namesake crustacean.

Kristin Shaw

While Colville had years of lead development engineering roles under his belt, handling things like ride handling noise and vibration, he had also built an impressive resume of software experience. He created a niche for himself, bringing his software influence into his vehicle performance job. His role developed as the person who would make sure the software integrated with the hardware to make their dreams of Watts to Freedom and CrabWalk come to fruition. 

“Josh [Tavel, the executive chief engineer for the Hummer EV] had lots of vehicle performance background as did program engineering manager Scott Damman," Colville remembered. "We were tapped out on vehicle performance background but no one else really had any software experience. So I became the figure-out-how-to-get-the-software-and-feature-content-to-work-to-make-it-awesome guy. Software defines vehicles today as much as pieces and parts, to a certain extent.”

As details of the Hummer EV came more sharply into focus, some of the engineers had different ideas on how to accomplish everything they wanted to create. 

"I remember Josh busting my butt a whole bunch because his vision was to have a little knob on the dash to turn back and forth to control the rear tires," Colville said. "But that really takes two brains. We’ve only got one brain."

They came up with three choices: CrabWalk; auto, which Colville says is the opposite of CrabWalk with a tight turning radius; or off.  Then they tuned it for different speeds. 

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"Going back to my rock crawling days, if you had the rear steer turned really tight and you try to go up a steep hill, bad things can happen really fast," Colville said. "The rear of the vehicle will want to come around on you and suddenly you’re not going up the hill but across it; that’s not what you want. That’s why vehicle speed comes into it. As the speed goes up, the rear tires begin to point more straight to give more stability." 

Colville was adamant that the Hummer EV needed to be legitimate to the people he races with off-road.

Kristin Shaw

“All my friends have seen the race cars I’ve built in my garage,” he said. “When people figured out what I was working on, they had hopes it would turn out cool but maybe they had doubts. I think we proved any doubts wrong.”

After spending a couple of days with off-road and on-road in Arizona last week, I'd say he's probably right. Even if you think the Hummer EV is a monster that most people shouldn't be trusted to drive capably, you can't help but be impressed. I could see where GMC is repurposing technology like the same camera setup that the Sierra debuted a few years ago, and then taking the features up a notch from there. This is a benchmark vehicle, and it's going to pave the way for more innovations from Colville and the rest of the GMC team in the future. 

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