ARB Air Lockers®

A relentless commitment to research and design, the use of quality materials, and an uncompromising approach to manufacturing have all contributed to the Air Locker’s success in over 100 countries worldwide. Designed and manufactured in Australia, ARB Air Lockers locking differentials will enhance the traction of your 4×4 in just about any terrain, whether it’s rock, clay, gravel, sand, snow or mud.

Now with a state-of-the-art two piece design available right across the range, forged gears for the ultimate in strength and durability, and an industry-leading five year warranty, ARB Air Lockers are better built and better backed than ever before. Many people believe that a 4WD and traction go hand in hand… you can’t have one without the other. However, your vehicle’s standard (or open) differential is designed to allow each wheel to turn independently, thus eliminating binding during turns. Off road, this becomes a major burden as engine power will take the path of least resistance, which occurs at the wheels with little or no traction.

Newer vehicles with limited slip differentials may offer some improvement, but more often you’ll find the slipping is not ‘limited’ enough to maintain forward progress. Automatic locking differentials also have their disadvantages. Aside from being noisy when disengaging, they can also upset the on-highway driving characteristics of your vehicle.

 

Forged Gears

Strength, durability and resistance to fatigue in all Air Locker® components is paramount. With phenomenal forces being applied to the side and pinion gears within the differential, ARB has invested heavily in the application of forged gears, typically found in heavy duty commercial, race and agricultural transmissions. When combined with ARB’s patented ‘timed gear’ design, the resulting strength of the whole assembly is amplified.

Two-Piece Design

Housing this superior internal gear train in a two-piece case brings further benefits. Machining a case from two-pieces instead of three results in a much higher dimensional accuracy of the finished assembly and has allowed ARB Engineers to improve the design of other elements, resulting in a reduction of moving parts, increased strength and a more responsive activation.

Unrivalled Support

For total peace of mind, all ARB Air Lockers® are backed by a comprehensive, five-year, unlimited miles warranty. Coupled with ARB’s extensive dealer network, you can be sure we’ll be there to support you in the unlikely event of an issue.

OFFICIAL LOCKING DIFFERENTIAL OF ULTRA4 RACING & KOH

The ARB Air Locker and ARB Air Compressor, are the official locking differential and air compressor of the Ultra4 race series and King of the Hammers, which are regarded as some of the most technically challenging races in the world.

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Air Supply

At the flick of a dash-mounted switch, compressed air is delivered to the seal housing assembly via a nylon air line.

Air Supply

At the flick of a dash-mounted switch, compressed air is delivered to the seal housing assembly via a nylon air line.

Flange Cap Assembly

A billet-machined, alloy steel spider block supports the cross shafts, using the torque applied at each shaft to support the next shaft along.

Clutch Gear

ARB's patented locking system actually supports the side gear teeth, giving you more torque handling capability, exactly when you need it.

Bonded Seal

Steel reinforced, elastomer-bonded annular seal has been proven to handle 20,000+ cycles under the most extreme climatic temperatures on earth.

Two-Piece Design

Machining a case from two-pieces instead of three results in a much higher dimensional accuracy of the finished assembly and has allowed ARB Engineers to improve the design of other elements, resulting in a reduction of moving parts, increased strength and a more responsive activation.

Splined Side Gear

High-grade surface treatments, forged nickel alloy steel and ARB's patented timed locking system make this the most ‘lockable’ gear in the industry.

Wave Spring

Instead of a complex external actuator system to engage/disengage the lock, ARB Air Lockers® use up to 12 return springs to support the entire profile of the locking gear for a fast, positive and independent disengagement.

Spider Block

A billet-machined, alloy steel spider block supports the cross shafts, using the torque applied at each shaft to support the next shaft along.

Pinion Gear

Combining the strength of forged nickel alloy steel with redefined gear-tooth geometry, ARB has revolutionized locking differential gear design to yield structural advantages of up to 30% over commercially available high strength gears.

Cross Shaft Retaining Pin

Custom made, one-piece hardened retaining pins lock into the assembly using a tapered thread junction.

Forged Gears

With phenomenal forces being applied to the side and pinion gears within the differential, ARB has invested heavily in the application of forged gears, typically found in heavy-duty commercial, race and agricultural transmissions.

Diff Case

Fully machined, one-piece nodular iron diff carrier case offers the rigidy of a one-piece factory differential with twice the standard number of pinion gears to cope with the torque.

Long Cross Shaft

Alloy steels and performance surface technology make for a high-pressure running fit that can handle an enormous amount of punishment.

  • LET'S DEFINE 'TRACTION' AND 'DRIVE'

    In simple terms, traction is the resistance between your vehicle’s tyres and the ground which offers you, as the driver, control of the vehicle; no traction = no control.

    Drive is the delivery of torque and power; drive (with an appropriate amount of torque force) is what rotates our wheels and tyres against the track’s resistance.

  • HOW IMPORTANT IS TYRE CHOICE FOR MY 4WD?

    Tyres, their tread pattern and construction are one of the most important factors to the performance for your 4WD. Your tyres are the final piece of the puzzle in transferring the engine’s energy to the track so that the car can move forward.

    Tyres, however, are only able to move the car forward if it least one tyre can gain traction to the track surface and that tyre is also receiving enough drive (torque) from its respective differential.

  • WHAT CAN I DO TO IMPROVE TRACTION WHEN OUT 4WDING?

    The fact is, you will never be able to control the traction of the track surface, but you can control the type of tyres, the foot-print of your tyres (air pressure) and whether your tyres receive drive or not. All these things will hugely improve the likeliness of finding and maintaining traction.

    If there is no traction on the surface, you can have 4 wheels spinning and little to no forward momentum. So the first steps to improving traction are:

    • A good set of all-terrain or mud-terrain tyres
    • Always adjusting your tyre pressure appropriate for the terrain of which you are driving on

    Reducing tyre pressure (letting air out) increases the surface area that the tyre has in contact with the ground; more tyre on the ground means better load distribution and more track surface to get traction from. This is most important when driving on sand. The benefits of low tyre pressure can also be seen when navigating rocky terrain, where the tyres have an increased ability to shape themselves around objects on the track, helping us gain more traction.

  • WHAT IS A DIFFERENTIAL AND HOW DOES IT WORK?

    Your 4×4 has a front differential and a rear differential; a differential is designed to distribute drive to either the left or right wheel on each axle.

    Delivering drive to just one side of the vehicle is what allows your left and right wheels to spin at different speeds, which is imperative for on road cornering.

    By design, a diff will rotate the wheel with the least traction. So, when we are travelling off road, if one wheel is suspended in the air or is sitting on a very slippery surface, the differential will only delivery drive to the wheel with no traction.

    This works against 4WDers because you can very easily find yourself in a situation where one wheel on the front axle and one wheel on the rear axle has little to no traction. In this situation, neither of the wheels with traction will receive drive.

  • WHAT IS A SELECTABLE DIFFERENTIAL LOCKER AND HOW DOES IT WORK?

    A selectable differential locker is a full replacement differential which can be ‘locked’ by activating a switch from the driver’s seat.

    The locking function removes the differential’s usual capacity to split the drive left to right by binding the gears; this means that both wheels will always rotate at the same speed, until the locker is disengaged.

  • WHEN DO YOU USE A LOCKER?

    We’ve described the basics of how a standard differential works and why we need them on road, however, when it comes to 4WDing, it can cause issues when driving on uneven or muddy terrain, where it is common for one or more wheels to slip or become raised off the ground.

    The perfect time to engage a diff locker is when traversing low traction surfaces, whether they be slippery or overly uneven causing wheels to lift.

    Switching the differential to ‘locked’ will send equal drive to both wheels, meaning that both the wheel off the ground and the one firmly planted on the ground will have equal drive, allowing the wheel with the most traction to push you forward and continue on the track.

  • WHY DO I NEED A LOCKER?

    We need a locker to make effective use of all the traction available between our tyres and the surface of which we are driving on. Lockers give you the ability to take advantage of the traction that is available by supplying drive to all wheels.

    For example, when you are in 2WD mode, you have drive going to one of your rear wheels, giving you 25% of all available drive. Engaging 4WD mode will send drive to one of the front wheels also, giving you 50% of all available drive, this is where lockers come into play. Engaging your rear locker will send drive to both rear wheels, coupled with the drive going to one of the front wheels, will give you 75% of all available drive. Engaging the front locker with the rear locker will send equal drive to all 4 wheels, giving you 100% of all available drive.

  • WHAT ARE THE BENEFITS OVER OTHER TYPES OF LOCKERS?

    The main benefit that an Air Locker has over an electronic-locker is its instant activation. By comparison to the majority of electronic lockers, an ARB Air Locker engages instantly and at any speed; furthermore, an ARB Air Locker has no operating speed limitations.

    Being able to engage your locker ‘on the fly’ means you don’t need to lose your momentum before tackling an obstacle.

  • WHAT ARE THE BENEFITS OF HAVING AN ON-BOARD AIR COMPRESSOR?

    Having an on-board air compressor has many advantages other than a way to activate Air-Lockers. On-board compressors are also perfect for inflating tyres, cleaning car components such as door seals and air filters, inflating air beds or for basically anything that needs compressed air. Having on-board air becomes very handy to have in your vehicle, especially considering that you don’t have to find space to pack it, nor do you need to pull it out and connect it to your battery every time you need to use it.

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