The ultimate guide to gravel driving
Australia has a huge number of gravel roads. Some are in better condition than many of our bitumen ones, and others will rattle your teeth until you can’t wait to see bitumen.
However, anyone can drive on public gravels roads that they want, without the faintest idea of what they should be doing, and that is a problem.
When an oncoming vehicle passes you at 100km/h and leaves you completely blinded in a cloud of dust, with a cracked windscreen and multiple stone chips in your paintwork, it’s pretty obvious they don’t know how to drive on a gravel road.
In this post, we are going to cover the ultimate guide to gravel driving, so you look after your vehicle, reduce the chances of anything breaking, improve your safety and don’t upset anyone else using the same road. After all, we share the roads with each other and being safe and sensible should be high up on your priority list. If its not, maybe stay home.
Gravel roads are vastly different
Firstly, if you haven’t done much gravel driving, they are nothing like a bitumen road, and they vary a lot in condition. Some are smooth and have lots of traction, and others have huge corrugations and lots of loose stones on top.
It is important that you adjust your driving style and tyre pressures to suit the road or you will join the thousands of other Australian’s that have had nasty accidents on a gravel road (and lots of injuries/deaths).
Punctures are not uncommon, as is a loss of control, or poor visibility due to dust clouds. Gravel driving is common and safe as long as you adhere to a few very simple practices.
Slow down when passing another vehicle
When you pass another vehicle going the other way, both cars should be going a maximum of 60km/h, and usually around 40 – 50 is better. This however, is entirely dependent on the width of a gravel road. If its wide, 60 is acceptable. If its narrow, slow down even more.
This does two things; firstly, it reduces the cloud of dust that you leave the other vehicle in (often to almost nothing – a few seconds later and they are back in the clear), and secondly, it reduces the rocks being flicked up. Once you’ve had a rock flicked into your windscreen from an oncoming vehicle going high speed, you’ll appreciate everyone who slows down.
Don’t overtake if you can’t see
Overtaking on gravel roads is usually not safely possible, unless the road is wide, or not very dusty. Its pretty simple; if you cant see with 100% clarity that it is safe to overtake, don’t. There’s been some terrible accidents, and even deaths in Australia from people who’ve gone to overtake, and been cleaned up by something going the other way.
Much like you’d be stupid to overtake a vehicle on the road over a hill, you are an idiot for trying to overtake someone on a gravel road without knowing that it is safe to do so. Not only do you risk your own life, and those in the vehicle with you but you risk the lives of innocent people coming the other way.
Let your tyre pressures down
Gravel driving can be extremely hard on your vehicle (and trailer if towing). By letting some air out (usually around 30% of your normal tyre pressure), your vehicle will ride smoother, which means a better ride for you and your family and everything attached to your 4WD is less likely to break.
People often think that 4WD’s break the most when they are doing a nasty track, but the silent (or not so silent) killer of 4WD’s is endless corrugations.
Lower tyre pressures gives you more surface area of rubber touching the ground, which increases traction, reduces the chances of punctures and acts as another part of your suspension, absorbing the bumps and corrugations.
Be very wary of when you check your tyre pressures, as they will change a lot depending on how long you’ve been driving for, and on what terrain. For more information on this, have a read of 4WD tyre pressures; do you check them hot or cold?
If all four wheels are driving on your 4WD, you have much better control on a gravel road. When it comes to going around a corner, 2WD vehicles will lose control much, much faster than a vehicle that drives all four. Beyond this, you’ll get much better wear from your tyres as its not just the rear ones doing all the work, and your safety is greatly increased.
A lot of 4WD’s these day are shift on the fly, so you can go between 2WD and 4WD without even having to stop. Consult your owners manual for more information! At the end of the day though, traction is king.
Pick a speed that is safe and comfortable
On a badly corrugated gravel road, the faster you go, the more comfortable it is. Unfortunately, the faster you go, the more unsafe it is. This is because as you speed up, your tyres contact less and less of the gravel (which is why its more comfortable).
First and foremost, your speed should be one that is safe. Experiment with speed and tyre pressures until you get it as comfortable as possible, but still safe. On a really, really badly corrugated gravel road you will have to take each corrugation up and down at a slow speed, or you’ll risk breaking something.
The other factor to consider is the damage to your vehicle. If you drive with no mechanical sympathy on rough, corrugated roads its only a matter of time until something breaks. The faster you go the easier it is on your vehicle, but don’t do it at a cost to your safety. You need to pick the speed that best balances safety, comfort and vehicle sympathy.
Use your radio
UHF Radio’s are amazing, and anyone who does a significant amount of gravel driving (or even driving outside of the city) should have one. They are fantastic for communicating to vehicles heading the same direction, and heading the other direction. The only problem, is if you don’t turn them on, they are a total waste of space. Keep them on channel 40, listen for other drivers and use them to make driving on gravel roads safe.
Let people pass if they want to go faster, tell people when you are pulling off the road to have a pee, or when a washout approaches. The more you use your radio, the safer it is for everyone behind you, and coming towards you. If you are travelling in a convoy they are great for having a chat and a laugh (on the right channel), and warning people of incoming vehicles or dips/holes in the road.
Clean your air filter out
At the end of a bad days driving on gravel, consider taking the time to remove your Air filter, and give it a good clean. Your manufacturer will advise the best way to do this, but normally a bit of compressed air in the direction opposite to how the air flows through is the acceptable method.
You can knock them against your tyres, but some filters will deform and get damaged. Be sure to install it back properly, so it seals as it should, or you can be up for some very expensive damage.
Of course, carrying a spare filter and replacing it instead of cleaning it out is another good option.
Turn your lights on
There was an old road campaign; be safe to be seen, and be seen to be safe. If you have your lights on, you are far more visible when its dusty and dirty. Turn your lights on when driving on gravel roads. It’s super easy to do, and very important.
Use a good air filter
Air filters are not all equal. Some aftermarket ones are good, and some are absolutely garbage. Running an oiled filter for example in a vehicle that runs a MAF sensor (which most modern ones do) can be a recipe for disaster. K and N filters, or pod filters are for street use only and should not be used in dusty conditions.
As many 200 series Land Cruiser owners will attest to, dust getting through the air box and into the motor can be a 20 – 30k repair bill. You just slowly eat the motor out. Not good.
Stay a decent distance behind
When you are following another vehicle, you shouldn’t be driving in their dust. That means you leave a gap of at least 300 metres, and sometimes a couple of kilometres depending on how bad the dust is. Slow down to match their speed, and stay far enough back that you aren’t sucking in their dust. This is substantially better for your motor, is much safer and more comfortable.
Fit a pre-filter
Some snorkels will take a pre filter, and although they look strange, they are very good. Ever wondered why some vehicles have a cyclone, or pre filter bowl at the top of their snorkel? This takes out a huge amount of bigger pieces of dirt and dust, and stops it ever making it into the air filter anyway. If you don’t want a pre filter, consider a snorkel sock to catch the bigger chunks, that you wash out regularly.
Be prepared for wash outs and road damage
Gravel roads can change condition a lot. Sometimes they are flat as, with plenty of traction. However, dips in the road, wash outs and pot holes are common and if you hit one at speed, it can end in tears. Always scan ahead to make sure there’s nothing coming up, but learn to judge and predict the road.
Where the topography allows for water to run across a road, you will end up with wash outs. On the Savannah way up north for example, you are constantly going up and down, and some of the changes in angle can be very sharp and dangerous if you hit them at speed.
Be ready to stop in a hurry, or to wash a lot of speed off before you hit wash outs, pot holes and crossings.
Check your nuts
At the end of the day, or the start of a new one you should make a habit of checking your wheel nuts and having a look under the vehicle. Gravel is notorious for making nuts and bolts come loose, and a few minutes on the tools can save you huge heartache when a wheel comes off and passes you at 100km/h!
A lot of accidents involving gravel happen when drivers change direction too quickly. You should never swerve on a gravel road. Try and gently adjust your direction, or take the hit. This is especially the case for animals; do your best to avoid them, but you are better to hit one than swerve and loose control.
Like the rest of Australia, gravel roads are driven with the ‘keep left’ taking priority. If the road is very wide, and you can see a long way in front some people like to sit in the middle, or right side of the road to avoid some of the nasty corrugations, but you need to be safe about it, and allow ample room to move back over, or for people to overtake as required.
Watch the suspension
One of the reasons remote reservoir shock absorbers have become so popular is due to endless corrugations. If you hop out and measure the temperature of your shock absorber after some nasty gravel driving, it will be very hot. The hotter the shock absorber gets, the less efficient it gets, until it performs very poorly.
On a nasty gravel road shock absorbers are crucial, so heat fade is a big problem. The way to overcome it is to have larger shock absorbers that dissipate heat better, or to have quality aftermarket gear that is designed to take more of a beating, like remote reservoir shocks.
The suspension your 4WD comes with from the factory is OK for some gravel driving, but if you punish it things will start to go wrong quickly. Suspension is one of the most important upgrades you can do for lots of gravel driving.
When it rains
Gravel driving changes significantly when a bit of water arrives. Tracks can become undrivable, extremely slippery and in many cases they get closed. You should not be driving on a gravel road if you are damaging it, as it costs a significant amount of money to repair and you are likely to get stuck and stranded anyway.
Take extra care driving on wet gravel roads, as they can turn to ice in terms of traction and you wouldn’t be the first person to take a corner and end well off the road!
Drive to survive
At the end of the day, you want to arrive at your destination alive. There’s no point putting lives at risk to arrive at camp 10 minutes earlier. If you get stuck behind someone, consider pulling off and having a break, or a bite to eat. On the Gibb River Road in 2018 we got stuck behind heaps of people going very slowly, but as it wasn’t safe to overtake we just hung back and cruised. Drive to survive!
What else have I missed? What’s your worst experience on a gravel road?
Interesting comment, and not something I’ve heard before. That said, I’ve seen stones do some awfully interesting aerobatics.
Slowing down is respectful in terms of dust and safety too, but I’ll have a think about stone directions some more!
All the best
It’s a common misconception that the other vehicles speed does the damage, but when it comes to stone damage, it’s almost entirely to do with YOUR speed. Moving vehicles kick stones up, or out the back, not forward. If an oncoming vehicle is only doing 40 while you’re doing 80, you’re the one copping stones at 80kmh, while he will only cop them at 40kmh. So slowing down is not so much considerate as saving yourself.
I probably wouldn’t change the tyre pressures at all if it got wet. Just reduce your speed if its slippery, or find an alternative route if its dangerous or wrecking the road. If it got muddy, then you could reduce your speed and pressures a bit.
All the best
Very informative. Thanks. Question: If you are driving on gravel road with tyres deflated to 25 and it turns very wet with still a long way to go, what tyre pressure is advised when driving in wet dirt roads?
You are very welcome!
All the best
Tks for an informative article, learnt a lot. This will come in very handy when we get on and off the tar.
I’ll be saving this for future ref.