ARB Air Lockers

What is a Differential?

When a vehicle goes around a corner, the wheels on the left and right side of the axle travel a different distance. So, if the vehicle takes a left turn, the wheels on the right will travel a slightly longer distance than those on the left. This is made possible because the vehicle has a differential or ‘diff’ on its axle which acts to send power to the wheel with the least resistance.

The Issue With a Standard Differential Offroad

The majority of vehicles have ‘open differentials’ or ‘open diffs’ because they spend most of their time on tarmac and in the city, where they need to be able to take turns. However, this causes problems when offroad because the power is sent to the wheel with the least resistance, so the wheel with the least amount of grip will spin. When travelling over uneven terrain, it is inevitable that one wheel will slip or come off the ground. An open diff will send all the power to that spinning wheel, and your 4 wheel drive vehicle can quickly become struck. Modern vehicles have tried to counteract this with advanced traction control systems, however, these rely on the application of the brakes to work, so they can quickly kill any momentum gained. Therefore, in the desert, they can be counter-productive and are best deactivated.

What is a Differential Lock?

Differential locks or ‘diff locks’ solve this problem by mechanically ‘locking’ the wheels on each axle together, so they are forced to rotate at an equal speed. Therefore, even if one wheel is on slippery ground, or is in the air, both wheels will be moving and so the wheel with grip will help to move the car forward. Diff locks offer the best of both on-road comfort and offroad capability and are much more effective compared to traction control systems or limited-slip differentials.

Are All Differential Locks the Same?

No, not all diff locks are created equal! When choosing a diff lock, there are two main options: an E-locker and an Air-locker.

E-Lockers

These are the most common type as they come standard on some four-wheel-drive vehicles from the factory, but are usually only available on certain, more expensive, variants in the model range. For example, the Jeep Wrangler only offers diff locks in the top-spec ‘Rubicon’ model, with the standard vehicle only available with traction control and a less effective ‘limited-slip differential.

These factory diff locks use an electromagnet to lock the axle together, converting the differential into a ‘spool’ with both wheels rotating at the same speed. As they only need 12v power, rather than an air compressor, they are somewhat less complicated than air lockers. However, E-lockers rely on roller cams for engagement so the vehicle must be stationary to engage and once the switch is flicked, the wheel must rotate slightly before they fully lock. This means that there is a greater risk of damage to the internal components of the differential and so more care needs to be taken when using E-lockers when compared to air lockers.

Air Lockers

These are the most common aftermarket differential lock and ARB’s Air Lockers are the best on the market. The ARB Air Locker is a direct replacement for your existing open differential and, because they are purpose-built for offroading, they have stronger components that are more reliable.

Unlike the E-locker, the ARB Air Locker has an external air compressor that applies pneumatic pressure to a locking collar that locks both sides of the axle together. Although this means that you need to install an ARB Air Compressor (or equivalent) to apply the pressure, this is beneficial for a number of reasons.

Firstly, having an air compressor built into your vehicle means you then have a convenient source of compressed air that can be used to quickly inflate your tires when offroading, clean equipment or pump up camping mattresses.

Secondly, and most importantly, ARB Air Lockers engage almost immediately because they rely on pneumatic pressure which means that they can be engaged ‘on the fly’ at any speed, so you can maintain momentum when negotiating obstacles off-road. 

This is particularly useful in the desert where maintaining momentum is crucial. What’s more, the X-Quarry Offroad Park has recently opened, with a whole range of moguls, cross axle obstacles and suspension articulating courses which can only be safely overcome with a reliable diff lock like the ARB Air Locker.

The Bottom Line

Ultimately, if you are going to be doing any hard offroading, a differential lock can help you to travel further over challenging terrain and, if you get stuck, will make self-recovery far easier. The ARB Air locker takes all the benefits of a traditional diff lock and puts them in a stronger, more reliable and more effective package. So, if you want to explore more of the outdoors without worrying about not making it home, then get in touch for a quote or join us on a drive for a demonstration.