What are those little yellow arrows for on car wheels?

You might’ve seen those little yellow arrows fitted to bus and truck wheels, but they have since made their way onto cars. So, what are they for?

Due to the sheer density of heavy vehicles in Australia, there’s a good chance you would’ve spotted these weird little wheel nuts that seem to be in the shape of a yellow arrow.

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Up until recently, they have only really been used for trucks and buses, but they have slowly been making their way onto large vehicles such as big utes.

The most obvious example is the new Ford Ranger Super Duty; a more heavy-duty version of the existing Ranger, putting load-carrying capabilities higher on the priority list than passenger-carrying capabilities.

That means additional underbody protection, a larger 130-litre fuel tank, raised suspension, and a strengthened chassis to cope with the increased carrying and towing loads.

It also means different wheels, and if you are even more eagle-eyed, you may have noticed that the uprated wheels have eight studs rather than six, which was previously the most you’d find on a standard road-going car you can buy new in Australia.

On all eight of those wheel nuts, you might’ve spotted bright yellow pointers on there, similar to that of the aforementioned heavy vehicles. But, what are they actually used for?

What are wheel nut indicators?

You’ll typically find them in yellow, but they can occasionally be black and they’re called wheel nut indicators or loose nut indicators. They do precisely what the name describes – provide a visible indicator that your wheel nut isn’t as tight as it was before.

The idea is that you tighten your wheel nuts to the specified torque, then place the wheel nut indicator over the top, with the arrow facing toward the other nut. If you drive, and the arrows are all pointing in opposite directions, it means that the wheel nuts are loosening themselves off.

While they are not a legal requirement for heavy vehicles in Australia, most companies that use fleet trucks will use them to keep an eagle eye on the nuts.

Using the Ford Ranger Super Duty as an example, the model has a $150 option to apply these indicators to the trim levels that utilise steel wheels, as does the Toyota HiLux.

Because these lower-trim-level vehicles are often used for fleets such as rentals and mining, Ford Australia says that it allows the company to keep a close eye on whether a nut wasn’t tightened properly, especially when maintaining multiple vehicles at once.

“The optional Wheel Nut Indicators were introduced to the Ranger Super Duty line-up and are commonly used by commercial vehicle operators, particularly within the agricultural and mining industry. Wheel Nut Indicators provide a quick visual check that the wheel nuts are torqued during pre-drive inspections; a process that the majority of commercial vehicle fleets employ on a daily basis,” a spokesperson for Ford Australia told Drive.

The thing these utes have in common with large commercial vehicles such as buses and trucks is that they are heavy-load-carrying vehicles, and a couple of loose nuts could spell disaster when fully loaded. That could be stripped wheel studs, snapped studs, or even losing a wheel completely while driving.

Being bright yellow, they also provide additional visibility for mining fleets that add fluorescent yellow stripes to the side of their vehicles.

If you want to add a set to your car, you can often find them online for as low as $30 for a set.

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