Why you should upgrade your 4WD tyres

So you’ve bought a new ute or SUV and you’re ready to head off into the Great Aussie Outback with caravan or camper trailer in tow. Congratulations! But, not so fast…

While your new rig may have been engineered for some of the world’s toughest terrain, there’s one aspect that could prove a weak link in the remoteness of Australian Outback: its tyres.

Most SUVs have rubber best suited to freeways and the suburbs. And while they’ll possibly do a fine job on some fairly gnarly rocks and gravel, their resistance to punctures isn’t always up to the hardiest and most determined of Australian rocks or tree roots.

Before we dive into the detail about tyres and off-road travel, here are some key tips:

Tyres are a balancing act

Blame it on engineers. They often analyse dozens of different tyres and ask tyre manufacturers to tweak the tiniest detail to ensure it works well on their car.

Key considerations include grip (cornering, braking and acceleration) on multiple road surfaces – including wet bitumen, dry bitumen, gravel, mud, sand and snow – as well as quietness, ride quality and refinement.

Cost is also a big consideration, as is rolling resistance (how much energy a tyre soaks up by rolling on the road), which has a direct impact on fuel consumption.

Throw all those aspects into the mix and the tyres that typically get chosen for a new Toyota LandCruiser, Ford Ranger, Nissan Patrol or Land Rover Defender tend to have a keener eye on everyday bitumen running than rollicking over the rocks of the Flinders Ranges or the sand of the Simpson Desert.

Consider more serious tyres

Many people throw chunky tyres on because they look good. Those driving in the bush or Outback do it because they’ll hopefully save them a puncture (or two, or three).

Those big chunky tyres – typically marketed as all terrains (A/T) or mud terrains (M/T) – usually come with thicker casings, tougher rubber and deeper tread blocks.

Usually… Because here’s the trick: There is nothing that defines an A/T or M/T tyre other than the marketing department of whichever brand manufactured it.

Some A/Ts are fairly mild (we’d include those fitted standard to the Toyota LandCruiser and Nissan Patrol). Others – including those on the Ford Ranger Raptor – are properly butch.

With all things tyres, though, there are compromises.

Chunky tyres typically make more noise once rolling down the freeway. That can get seriously annoying after a few hundred kays – let alone a few thousand. Most are not as efficient on the road either, because the engine has to work harder to keep those tread blocks rolling. They may also have less grip on bitumen, particularly in the wet.

Plus, they can negatively impact how your suspension deals with bumps and even steering response because the big chunky tread blocks squirm around more.

Our recommendation would be to do your research on some A/T tyres. M/Ts generally bring too many compromises and are best left to the hard-core off-roaders.

Size does count!

Bigger ain’t necessarily better once you venture beyond the blacktop, especially if you’re talking the diameter of the tyre (which measures in the internal diameter).

Manufacturers of luxury SUVs love enormous wheels and tyres, often up to 22 or 23 inches in diameter. But as a general rule, the larger diameter the tyre, the slimmer the sidewall (lower profile).

Less air between the road and the wheel rim means less chance for the tyre to deform around rocks, logs or ridges. All of which means you’re more susceptible to damage. And sidewall damage is the end of any tyre. Any damage to a tyre’s sidewall is irreparable, so you’ll be up for a new tyre.

So while you may be tempted by those huge rims in the showroom, consider the rubber wrapping them and how it might deal with rocks, mud, sand and sludge.

Bigger tyres are also harder to replace in the Outback. There are often tyre repair places dotted in some of the most remote locations – a pub or roadhouse, for example – and they’ll usually carry a selection of spares.

But they’ll stock what they’re likely to sell, which typically means 15, 16, 17 and 18-inch wheels. You’ll occasionally find 19s, but 20s, 21s and 22s are about as prolific as honest politicians.

Consider taking a second spare

Clearly you want at least one spare tyre for remote travelling. But it’s also worth considering a second depending on where you’re planning on going.

Even if you just take the tyre (without the rim) it could come in handy. You’ll easily find places which can switch that second spare to one of the five other rims (the four on the car plus the spare).

If you’re popping new tyres on before heading off on the Big Trip, then consider holding onto one of the tyres you were going to throw out. A used spare is better than nothing when the nearest town could be hundreds of kilometres away and the closest big-brand tyre retailer further again.

So if you’ve got space on the roof, consider a second spare.

Practice before you take off

A no-brainer before you take off is to practice changing a tyre before you hit the road. At the very least it’ll let you know if you’ll actually be able to get the nuts off the wheel.

Don’t laugh. Many mechanics tighten tyres with a rattle gun and there isn’t a bicep in town that will be able to loosen that bad boy once it’s on the car (tell your mechanic to hand tighten the nuts before you hit the road, or at least ensure they’ll be removable with a wheel brace).

Getting to grips with a tyre change will also familiarise you with the tool kit location and the jack, some of which will require some serious unpacking to locate.

Most cars come with the cheapest jack the bean-counters can get away with and they’re usually fiddly and difficult to use. If you’re travelling with friends it could be worth bringing a trolley jack that will be so much easier to use.

And at the very least, throw in a solid block of wood to pop under the jack (the weight of a car means a jack can sink into gravel or sand).

Changing a wheel will also be a reminder of how clunky it can be lifting 20-plus-kilograms of wheel-and-tyre and guiding it on to the hub. Again, practice it in suburbia rather than on the Birdsville Track…

Keep an eye on pressures

Tyre pressures are a key consideration in Outback driving. Many recommend dropping your pressures slightly once you hit the gravel.

Exactly how much will depend on your tyres, how much weight you’re carrying and how fast you’ll be driving. In other words, it’s a long way from an exact science.

Tougher tyres with a taller sidewall might be able to run 5 or 10 psi under their regular pressures, generally a lot more if you’re travelling at 70km/h or less.

But if you’re running lower-profile road tyres then you’ve got less leeway.

And if you’re driving closer to 100km/h with a heavy load on board you don’t want to be dropping much from what the manufacturer recommends, purely to reduce the chance of heat build up (which can lead to a blowout).

Whatever pressures you’re running you want to be monitoring them in real time.

Many Outback punctures are slow leaks that could be easily repaired. But if they go unnoticed and you’re driving on them the tyre can easily be destroyed very quickly.

If you get a fast leak and travel only a few hundred metres on that flat tyre you’ve likely shredded the steel belts that are a critical component of the tyre construction. A repairer will know, too, because there will be rubber powder inside the tyre when they take it off the rim.

Get a slow leak and you risk a build-up in heat that will likely result in a blowout. That means you’re up for a new tyre (and you could also damage the car on the way through).

So if your car doesn’t have built-in tyre pressure monitoring, buy a set of tyre pressure sensors. External sensors are the easiest to fit, because they screw straight onto the valve then communicate via Bluetooth with a display that sits on the dashboard. Prices start at less than $200, which is way less than you’ll pay for a tyre in the middle of nowhere.

Be aware, though, that your tyre pressures and temperatures will naturally increase while driving due to the friction created by flex in the tyre as it rolls. How much those temperatures and pressures will change will depend on your car, the tyres, the pressures you started with, the ambient temperature and even the angle of the sun (the sunny side of the car will typically get more heat in the tyre).

The main thing you want to monitor is that the tyres (particularly one tyre) aren’t building excessive heat and are all broadly aligned – remembering that if the sun is setting on one side of the car your temps could rise slightly on that side.

What if I get a puncture?

If you do lots of Outback touring a puncture is a matter of ‘when’, not ‘if’. It’ll happen, as any remote tyre repairer will tell you.

When you do get a flat, it’ll likely be the back tyre that goes down. That’s because at speed your front wheels can flick rocks around and they’ll inevitably flick a sharp rock on the wrong angle for the back wheel, positioning it perfectly to pierce the tyre.

That’s when air starts escaping. If it’s a slow leak you may be able to temporarily manage it by refilling it with air (travelling with a compressor is essential for Outback touring). Otherwise pop the spare on and keep motoring.

But you want to get the tyre repaired as soon as possible. Anything that vaguely looks like civilisation – a pub or petrol station or even a general store – could have facilities to fix a tyre. Outback stations could also sometimes help if you’re desperate.

So ask the question and someone should at least be able to steer you in the right direction.

The type of repair makes a difference

The best type of repair for a flat tyre is a patch. It involves removing the tyre from the wheel and gluing a patch to the inside of the tyre to cover the hole. If it’s only a small hole the tyre should be like new when fixed.

Some places may only offer to plug the tyre (you can also take plug repair kits with you). Plugs are fine for small holes and punctures from things such as nails, but they won’t work if there’s a slash or longer cut.

As the name suggests, a plug will plug the hole. You’ll usually have to bore the hole out so it’s large enough to accept the plug.

Then you’ll need some muscle to plunge the sticky plug into the hole where it will hopefully stop air escaping. They can work perfectly, but plugs can also be hit-and-miss. Try for the patch first but go for a plug if there aren’t other choices.

Another backup for a slow leak is a can of ‘goo’. These fill the tyre with a sealant to hopefully stop the leak. Again, they can work well as a temporary fix, but won’t tackle a larger gash.

Also keep in mind that tyre repairers don’t like dealing with the goo when it comes time to replace or properly repair the tyre. So, again, consider other steps before reverting to the can of goo.

Tyres are important

Hopefully by now you’re getting the message that tyres are one of the most important components of a 4x4 ute or SUV when you go bush.

Crucially, you need to think about them before you hit the road. Doing so will ensure you’re prepared for punctures, adjusting tyre pressures and whatever else you may need once civilisation disappears into the rear-view mirror.

And don’t go looking for that elusive perfect tyre. It doesn’t exist, never will. All tyres have compromises and all are optimised for certain conditions or types of driving.

Choose the tyre that’s right for your car and the trip you’re planning.

Oh, and enjoy the trip!