4th January, 2019

January 3rd, 2019/Seattle, WA – ARB 4×4 Accessories is proud to announce a new partnership between ARB and Ultra4 Racing. The ARB Air Locker and ARB Air Compressor, both already renowned and respected in the off-road racing industry, are now the official locking differential and air compressor of the Ultra4 race series.

King of the Hammers, an Ultra4 fan favorite, began in 2008 and was instantly regarded as one of the most technically challenging races in the world. Since the first official race in 2008, ARB has been a frequent vendor displaying the latest product and has continued technical support to all those competing. Ultra4 racers know they can not only count on the reliability and durability of ARB products, but also the ARB team to be knowledgeable and supportive during the race week.

The extreme racing conditions of the King of the Hammers has driven ARB product improvement. From the abuse that Air Locker® endure during the race; engineers have made continuous improvements over the years. Such improvements include new heat-treating processes, forged internal gears, and a new-wave spring for faster disengagement. These improvements have been implemented across the entire Air Locker® product line to ensure that both your daily driver and weekend trail wheeler have the latest Air Locker® technology available to take you wherever you want to go.

ARB’s dedicated team of engineers recently developed, two competition edition Air Lockers®. Based on the Ford 9” differential, the RD99CE (35-spine) and the RD249CE (40-spline) pushed the limits of Air Locker® design. New features were developed like a ring-gear bolt-locking system and a supercar heat-treat process that improved the overall case strength by 290%. All of these changes make the competition edition lockers the perfect choice for serious Ultra4 and rock-racing racers.

Since its release, the competition Air Locker® has taken the rock-racing scene by storm. Air Locker® equipped vehicles showed their extreme reliability by winning numerous races including the past two King of the Hammers in cars piloted by Shannon Campbell and Jason Scherer.

If you are a competitor, ARB will once again be offering a contingency payout to the winners. For more information or to signup, please visit –

About ARB 4×4 Accessories

Founded in 1975 in Melbourne, ARB 4×4 Accessories is now Australia’s largest manufacturer and distributor of aftermarket 4×4 accessories. With products including winch bumpers, protection equipment, Old Man Emu suspension, Air Lockers®, compressors, roof racks, recovery equipment, and freezer fridges, our primary mission is to prepare vehicles for the remote and harsh conditions typically encountered off-road. ARB currently has 45 stores throughout Australia, over 300 authorized dealers across North America and an export network reaching more than a hundred countries.