My Hummer EV's Suspension Is Unstable Since Installing 38-inch Tires, And I Can't Find a Fix

There’s a certain romance in breaking new ground, especially when it involves a 9,000-pound, 1,000-horsepower electric vehicle with more torque than a diesel locomotive and the curb presence of a freight train. The GMC Hummer EV is a triumph of audacity and a rolling embodiment of what General Motors imagines the electric future should look like.

But when you venture off the OEM path, things get complicated, fast. Lift kits and oversized tires have long been the calling cards of off-roaders and parking lot gladiators alike, but doing it to an EV? That’s a whole different can of worms.

‘38-Inch Tires’ Cause a Bouncy, Unstable Ride

"Put this thing on 38’s today, it rides terrible. Has anyone put lift links on, Hummer is super bouncy now and all over the road? Whats the fix….."

That quote pulled straight from the trenches of a Hummer EV owner’s forum, reads like a distress call from the front lines of a new frontier. And it should. While traditional trucks have a century’s worth of tribal knowledge to fall back on when it comes to modifications, the Hummer EV is still something of a prototype, a beta test wrapped in carbon-fiber skid plates and powered by a platform we’re only beginning to understand.

How Changing Suspension Geometry Impacts EV Performance

Any time you lift a vehicle, you aren’t just changing its posture, you’re rewriting its physics. Suspension geometry is a delicate dance of control arm angles, damping rates, roll centers, and steering feedback. 

Hummer EV vs. Tesla Cybertruck: A Performance, Design & Off-Road Comparison

• The GMC Hummer EV offers both dual-motor (570 horsepower) and tri-motor (1,000 horsepower) configurations. Its tri-motor variant accelerates from 0 to 60 mph in approximately 3.3 seconds, featuring a "Watts to Freedom" mode that unleashes maximum performance. In comparison, the Tesla Cybertruck provides single-, dual-, and tri-motor options, with the top-tier model boasting 834 horsepower and achieving 0 to 60 mph in about 2.6 seconds, utilizing its "Beast" mode for enhanced performance. ​
• The Hummer EV showcases a robust, muscular design reminiscent of the original Hummer, complemented by removable roof panels for an open-air experience and a spacious interior with high-quality materials. Conversely, the Tesla Cybertruck features a futuristic, angular exterior constructed from stainless steel, with a minimalist interior centered around a large touchscreen. While the Cybertruck's design is unconventional and polarizing, the Hummer EV offers a more traditional and versatile aesthetic, especially with its removable roof panels. ​
• The GMC Hummer EV is engineered for off-road enthusiasts, featuring air suspension, customizable ride height, and a revolutionary CrabWalk mode that allows the vehicle to move diagonally for better maneuverability. Not only is this helpful off-road, but it is also beneficial when navigating crowded cities and tight parallel parking spaces. The Tesla Cybertruck offers adjustable air suspension with up to 17 inches of ground clearance and self-leveling capabilities. However, the Hummer EV's purpose-built features and proven GMC off-road expertise provide an edge for serious trail enthusiasts.

Throw 38-inch tires onto a vehicle designed around 35s, and you’re adding unsprung mass, increasing leverage on every suspension component, and pushing the adaptive dampers into a range they weren’t meant to operate in.

The result? A plush, composed ride turns into a pogo stick on roller skates. That “super bouncy” sensation? That’s your truck’s suspension screaming for mercy.

How Bigger Wheels Disrupt Advanced Suspension Systems

More than just discomfort, the issue here is systemic. Larger tires affect everything from the toe and camber settings to torque distribution and regenerative braking behavior. On a gas-powered truck, the drawbacks are mostly mechanical. But on a vehicle like the Hummer EV, with torque vectoring, electronically controlled dampers, and complex software governing every movement, the consequences ripple through the entire architecture. You’re not just lifting a truck anymore; you’re disrupting an ecosystem.

Pioneering the Future of Electrified Off-Roading

And therein lies both the problem and the promise. The Hummer EV rides on GM’s Ultium platform, the same modular underpinnings that will support the upcoming Silverado EV, Sierra EV, and Cadillac Escalade IQ. This means the modifications made today aren’t just individual experiments; they’re case studies for the future of electrified off-roading. Get it right, and you might just pioneer a whole new genre of aftermarket performance. Get it wrong, and you could send the next wave of Ultium-based vehicles into the same unpredictable, willowy mess.

Hummer EV vs. Tesla Cybertruck and the Challenges of Tuning EV Platforms

In this war of EV titans, the Hummer EV stands as GM’s answer to the Tesla Cybertruck, a rolling rebuttal to Elon’s dystopian stainless steel slab. Where the Cybertruck is a tech bro fever dream, the Hummer EV is a nostalgic brawler reborn with a lithium heart. It’s brutish, absurd, and surprisingly refined when left untouched. But the minute you try to treat it like an old-school lifted Silverado, you discover how little we really know about tuning electric platforms. This is no longer about chrome grilles and Fox shocks, it’s about software integration, sensor recalibration, and keeping the whole system from descending into chaos.

From EV1 Setbacks to the Bold Electrification Journey of the Hummer EV

And yet, there’s a poetic irony to all of this. Bob Lutz, the same man who ushered the original Hummer into suburban driveways in the early 2000s, also killed GM’s first EV, the EV1, in a misguided bet on gasoline-fueled muscle over forward-looking innovation. That gamble cost GM decades of progress in electrification. Now, two decades later, GM’s redemption arc comes full circle, trying to electrify the same over-the-top ethos that buried its first EV attempt. The Hummer EV, in all its glory and clumsiness, is both the sequel and the apology. But if we’re going to rewrite the story, it won’t be Lutz or GM engineers doing it, it’ll be the guy in the garage wrestling with 38s and wondering what went wrong.

Images sourced from Chevy, and Facebook

Noah Washington is an automotive journalist based in Atlanta, Georgia. He enjoys covering the latest news in the automotive industry and conducting reviews on the latest cars. He has been in the automotive industry since 15 years old and has been featured in prominent automotive news sites. You can reach him on X and LinkedIn for tips and to follow his automotive coverage.