Corrugations are enough to shake up even the most experienced driver. To help reduce the impact on you and your van, Ian Bellert spoke with the experts on the best ways to drive on rough roads.
Of all the experiences when travelling our wide red land, corrugations are not the type of terrain anyone looks forward to. A day of driving on corrugations puts even the most hardened traveller, vehicle and van to the test. Is there any way to ease the pain? Ease, yes. Completely solve? No, that's the price you pay to get to some of Australia’s most remote areas!
We have researched and spoken to travel, suspension and tyre experts about the best way to deal with corrugations.
The corrugated Connie Sue Highway (Image Ron Moon)
Under pressure
The first constant is that lowering tyre pressures helps. It's an imprecise science due to the variations in vehicles, vans being towed, track conditions and so on, but running your tyres well below highway pressure will help. Around the 20–25psi mark is a good start, but it depends on your rig, what you are towing and the state of the road. Having your tyres at a lower pressure helps your vehicle and van’s suspension cope with the corrugations and your tyre remaining part of the suspension process.
Working out your ideal speed is critical to your comfort and your rig’s travel health. You will find slowing down helps, most recommendations are around 60–80km/h. Caravan World spoke with Ron Moon from Moon Tours, a man with more corrugation miles under his wheels than most.
Don't be afraid to stop and check your tyre pressures
Ron comments, “The word was, back in ‘the old days’ when suspension was leaf sprung and pretty agricultural, the ideal speed over corrugations was 80km/h or so. Now with more reactive suspension, i.e., coil spring, that no longer holds true. To 'float over the corrugation' in a coil sprung vehicle you gotta go way too fast and for both the shock absorber's liveability and your safety on quickly changing outback roads.
“In our travels we’ve found around 60km/h to be the best but the 'sweet spot’ for your vehicle may be a bit higher or lower. Going excessively quickly puts a lot of pressure on the shock absorbers and while you may feel you are floating over the corrugations don’t be surprised if your shocks fade … or worse. And, at those speeds on a rough dirt road or track you are setting yourself up for a major fail!” (Check out Moon Tours for great travel adventures run by Ron.)
Driving slower and with reduced tyre pressures will help reduce the hammering dished out by corrugations. Remember to reduce your van’s tyre pressures as well. Mostly they’ll be pretty similar on both car and van, but a lot depends on loads, roads, speed limit and how your rig is handling the ups and downs. Every little tweak helps and don’t be afraid to stop and tweak tyre pressures on the track.
Taking care of your suspension
Caravan World spoke with 4Way Suspension’s product development director, Simon Vella, for insights regarding your van and vehicle suspension when faced with corrugations.
The Gunbarrel Highway (Image Ron Moon)
Simons says, “Your suspension goes through about a million cycles a day on corrugated dirt roads.
"In preparation for a trip, start with the tyre, the second member of the suspension family. [The first thing to consider is] are the tyres on the van or camper trailer up to the load rating? Original Equipment (OE) tyres and rims are specific for the van or camper. Sometimes they can be swapped out for a better, tougher-looking tyre and rim set. Check that the tyres fitted have the load rating suitable for your van.
“As you traverse the corrugated tracks, the pressure in your tyres will increase. That excess pressure exerts force onto the shock absorber and the shock is now dealing with a tyre that has almost become a stone. It's hard and not absorbing any of the energy that is coming from the road surface. All the inertia from the corrugation goes through the tyre, into the wheel, into the axle and straight through to the shock absorber. Caravans and trailers being dragged over corrugations have a lot harder time than the tow vehicle. The ‘dragging’ effect actually increases the impact of the corrugations on the van's suspension system. Adjusting your speed to road conditions can reduce the impact of corrugations on your vehicle and van's suspension system.”
Run pressures that suit the track you're driving on
Simon’s last tip is “Get the tow vehicle and the caravan wheels aligned. It will save on vehicle wear and tear, fuel efficiency and overall performance. An aligned trailer or caravan can better deal with a corrugated road. The preference is to have the trailer alignment loaded with how the van is going to be used for the majority of its life. If its life is going to be heavily laden for constant touring, then ensure that it is fully laden when the alignment takes place. This will allow for maximum tyre life on the caravan and less stress on the tow tug, often avoiding excessive fuel consumption caused by the van fighting the tow vehicle.”
A wheel alignment on both your trailer and tow vehicle will help driving over corrugations
Stay vigilant
Constantly monitoring tyre pressures is also the advice offered by Russel Stewart, Bob Jane T-Marts National Marketing Manager. Russel tells Caravan World, “Heat is not a tyre's friend. Heat buildup in a tyre is caused by compression rather than friction. On a recent trip into the Simpson Desert, on particularly bad corrugations, our tour leader, Ben Carceller, director at Adrenalin Offroad Centre, suggested 14psi and a speed of 70km/h.”
Ben commented, “That particular stretch of road was 77km long. We deflated to low teens and drove 60–80km/h in 10km blocks. Each vehicle found their sweet spot in the speed range. Regular stopping allowed the tyres to cool while the driver did a quick safety check of the vehicle to make sure things were not shaking off the vehicle. A change of a few PSI can make a big difference to the vehicle's ride on corrugations.”
Russel continues, “Always check your tyre pressures in the morning before travelling, particularly if you’ve adjusted pressures on hot tyres the day before. Readings when a tyre is hot can give you incorrect pressure reading on your tyre gauge as the properties of the air in your tyres change due to heat. The key is to run pressures that suit the track you are on. Particularly remember to reinflate back to highway pressure when you hit the blacktop.”
Final advice
Unfortunately, a comprehensive solution on how to make corrugations bearable is not in the offing. It’s a little like the discussion around how corrugations are formed. There are some interesting theories out there, some of which well-known Australian scientist Dr Karl Kruszelnicki has explored, but there has not been any definitive answer yet.
Advice our experts agree upon is to make sure your tyres have the correct load rating for the vehicle and van. Continually check and adjust your tyre pressures to suit the track you are travelling on. A wheel alignment with your laden van and the tow vehicle will reduce stress and an aligned tow tug and van will handle better on a corrugated unsealed road. The speed at which you travel will have an effect on how your vehicle and caravan ride over corrugations. Finally, don’t be afraid to stop and tweak tyre pressures on the track. It's better to check and a few PSI either way (up or down) than relying on your vehicle and caravan’s suspension and tyres to deal with the corrugations while you grit your chattering teeth and hope for the best.
Now that you've heard these simple rules and tips from the experts, it's time to head off the beaten track. If you're looking for a good place to test out your new skills, check out the destinations below.
Caravans have a harder time on corrugations than tow vehicles
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Tips from the experts: How to drive on corrugations