King of the Hammers Classes Explained: A Look into Every Off-Road Race Class

(Header Image Source: Ford Racing)

Every February in Johnson Valley, California, the desert wakes up in a way most places never do. Hundreds of vehicles, from purpose-built race machines to nimble side-by-sides, line up in the dust with one goal in mind: to conquer the toughest one-day off-road race on earth. That’s King of the Hammers (KoH) - a grind of desert, rocks, endurance, and speed that has earned legendary status in the off-road world. (King of the Hammers)

But to fans and newcomers alike, the sheer variety of vehicles and race classes can feel overwhelming. You may hear “4400,” “4600,” “UTV,” or “Every Man’s Challenge” thrown around and wonder what it all means. So today, we’re breaking down the classes at King of the Hammers, explaining what makes each one unique, who’s likely to race in it, and why each has a place in this brutal week of racing.

The Heart of KoH: ULTRA4 Racing

At its core, King of the Hammers is built on ULTRA4 racing, a discipline that mixes high-speed desert endurance with technical rock crawling. These classes are the backbone of the event, and they represent the evolution of off-road performance from pure brawn to strategic engineering. 

4400 – The Unlimited Kings

If there’s one class that defines King of the Hammers, it’s 4400 – the ULTRA4 Unlimited Class. This is the “Race of Kings,” the premier division where the most advanced vehicles compete. These machines have virtually no limits on engine size, suspension design, or tire choose-your-own-adventure setup, beyond safety rules. That means massive powerplants, independent front suspension options, stacks of shocks, and custom tube-frame chassis designed for both high speeds across the lake bed and precise crawling in boulder fields. 

What makes 4400 special isn’t just how fast or capable the rigs are, it’s the engineering freedom racers have to innovate. Wheels, tires, engines, shock packages, and drivetrain systems are all optimized for the unique blend of speed and rock performance KoH demands. It’s the class where budget meets vision and where the most extreme builds come to shine.(Source: Driving Line)

4500 – Modified Class

Just one notch down from the unlimited beast is the 4500 Modified Class. These vehicles still pack serious punch and performance, but with more defined boundaries. Modified cars usually start with an OEM chassis or a close-to-factory frame design. Suspension upgrades are significant (typically multiple shocks per corner) but builders don’t get the same wide-open rulebook that 4400 teams enjoy. 

For many teams, the 4500 class is a proven stepping stone. It lets racers push harder than stock limits allow while still keeping build complexity and cost slightly more manageable than full-blown unlimited cars.

4600 – Stock Class

King of the Hammers isn’t just for highly modified machines. The 4600 Stock Class brings the everyday enthusiast into the action. These race vehicles retain their stock OEM frames, engines, and transmissions—meaning the bones of the vehicle are closer to what you might drive on the street. 

Don’t mistake “stock” for easy, though. These rigs still race the same punishing terrain and see significant upgrades like DOT approved tires, beefed-up suspension components, and other enhancements allowed within the rules. For many drivers, 4600 is about proving that with smart preparation and grit, a more relatable build can survive and thrive in one of the world’s hardest races.

4800 – Legends Class

Ever wondered what happens to old ultra4 cars that no longer meet the latest tech specs? They get a second life in the 4800 Legends Class. This class is designed to be competitive while keeping costs lower and builds simpler. Cars must run a solid front axle, a front-mounted engine, and adhere to shock and tire limits that promote reliability and class parity. 

Legends vehicles are tremendously fun to watch, because they often outperform expectations against newer builds due to experienced drivers and clever setups.(Source: David Chick)

EV – Electric Vehicles

In recent years, King of the Hammers has embraced innovation in an exciting way—by welcoming Electric Vehicle (EV) entries. That’s right: silent torque monsters now compete alongside internal combustion rigs, signaling that off-road racing evolution isn’t just about horsepower anymore. 

EV entries bring a novel edge to the desert, showcasing not only raw performance potential but how energy management plays into endurance racing.(Source: InsideEVs)

The UTV Revolution: 4900 and Beyond

Ultra4 racers aren’t the only stars at KoH. In fact, UTVs — lightweight, nimble side-by-sides — have become some of the most talked-about competitors. With separate classes under the 4900 UTV Hammers Championship, this segment continues to grow year after year. (King of the Hammers)

These classes typically include:

• Pro Stock NA UTV – Naturally aspirated UTVs with limited mods.

• Pro Stock Turbo UTV – Turbocharged models tuned for maximum speed and efficiency.

• Pro Modified UTV – Heavily enhanced machines with extensive aftermarket support.

• Open UTV – Fewer restrictions, allowing builders to really get creative.

• Sportsman Stock UTV and Youth 1000 UTV – Entry-level to grassroots competitors. (King of the Hammers)

UTV racing at King of the Hammers has invigorated the event. Riders find a more accessible route into competition, and these machines often deliver close, exciting battles through rocks and desert alike. With nimble handling and lighter weight, they offer a very different racing flavor compared to the big tube cars.

Youth and Specialty Races

KoH also celebrates up-and-coming racers and grassroots competitors with specialty events like the KOH Kids 170 Race, which offers Stock, Limited, and Modified classes for young riders eager to cut their teeth on competition. (King of the Hammers)

These races don’t just add diversity to the schedule—they help build the next generation of off-road racers, fostering skills, confidence, and passion for the sport long before racers graduate to full UTV or Ultra4 rigs.(Source: UTV Sports)

What It All Means

Behind every class at King of the Hammers is a story of ambition, engineering, and grit. From the build-it-from-scratch 4400 monsters to the stock-leaning 4600 stockcars, racers choose their path based on experience, budget, goals, and appetite for challenge. Whether you’re a fan of high-speed desert runs or slow-and-technical rock garden crawls, there’s a class that speaks to your kind of off-road obsession.

Most important, every class embodies the spirit of King of the Hammers: pushing man and machine to the limits and refusing to back down from whatever the terrain throws at them.