Towing a trailer off road; the ultimate guide
Taking your 4WD off road is a whole heap of fun, and gives you access to so many unbelievable places that many never get to see. A lot of people eventually end up with a trailer of sorts, and then want to also take this off road. It could be a caravan, a hybrid camper, camper trailer, off road box trailer or even a boat trailer.
Towing a trailer off road is vastly different to just driving your 4WD, and in this post we look at all of the factors you need to think about to ensure your trailer and 4WD come back in one piece, and you have an enjoyable time away.
To give you some history, we started our camping in a Hilux and tent, and then moved to an 80 Series Land Cruiser that we decked out to go basically anywhere we wanted it to go (as a tough tourer), and when we had our first kid we purchased a soft floor camper trailer.
Today, we use an Isuzu Dmax and a Reconn R2 for our family of 4 to travel in, and frequently take the trailer off road.
So, what do you need to think about when towing a trailer off road?
What is the trailer designed to do?
The first, and most important place to start is with what the trailer is actually designed to do, and then how far you are willing to push it. If you have an on road caravan, you’d bottom out on some big curbs on the bitumen and that makes it totally unsuitable for taking off road.
Clearance is the most obvious requirement when taking a trailer off road, but it goes beyond this. The chassis and structural integrity of trailers varies hugely, and you wouldn’t be the first person to have a camper trailer literally snap in half because its either been poorly made, or its been taken beyond its capabilities.
The heavier the trailer, the harder it is to tow, and the same goes for its physical size when you are taking it down tracks that are narrow, and many are.
Stick within the design parameters of the trailer that you have. If it’s an ex army box trailer you are probably right to take it just about anywhere as they are virtually indestructible. However, if it’s a big, heavy hybrid you aren’t going to be able to take it on the canning stock route, or on tracks requiring huge flex and clearance, as they simply don’t have what is required.
How does your 4WD suit the trailer?
There’s no doubt that some 4WD’s are better tow vehicles than others. Despite this, there’s a huge variety of vehicles that are used for towing trailers around, and how your vehicle matches the trailer is hugely important in terms of how far you can go.
Towing a heavy trailer with a low powered 4WD will make some situations off road extremely difficult. Yes, low range can help, but ultimately power is a must when it comes to soft sand driving, some mud work and there’s no substitute for it.
Likewise, having the most decked out tough tourer in the world is only so good if your trailer has no clearance, and is going to bottom out and get smashed up on the first major obstacle.
If possible, having somewhere balanced is the ultimate solution. If you have a low powered vehicle, get something that isn’t too heavy, or too big. If you have a vehicle that isn’t hugely capable off road, your trailer doesn’t have to be either.
In our scenario, I’d say our Dmax and Reconn match together pretty well. We aren’t at the end of our weight limits (although we are close), it has similar clearances and wherever we can take the Dmax the Reconn will follow (although we have damaged it!).
Dead weight hugely reduces your vehicles capability
Until you’ve towed a trailer off road, its hard to explain what dead weight does to your 4WD. What I mean by this is the trailer you are towing does zero work. It relies entirely on your 4WD to pull it along, and the difference off road is astounding.
Where you might scrabble up a steep slope with your 4WD only, hooking a trailer on can make you stop half way up and not be able to go any further no matter what you do.
This is most obvious on a soft beach, where even a 1 tonne camper trailer will often be enough to make your 4WD really struggle to drive along. Add in a trailer that is 2 – 3 tonnes, and your life gets a whole lot harder.
Hill climbs are the next difficulty, where the dead weight just reduces your vehicles capabilities hugely. Factor this in when you choose a trailer; there’s a reason that people avoid towing trailers altogether, or pick something that’s as light and small as possible.
Your vehicle has to work much harder
Going on from the above point about dead weight, your vehicle has to work a lot harder than it would not towing. This applies to everything from your tyres to suspension, driveline and so forth.
Whilst your vehicle might scrabble and bounce around trying to climb up an obstacle without a trailer behind it, the trailer makes everything work much harder.
The force on your CV’s, tyre tread, differentials and so forth is amplified hugely towing a trailer, and you need to factor this in. You might get away with pushing your 4WD a bit harder without a trailer on, but if you drive the same with the trailer you can find things might just go bang, and that’s never a good feeling.
Sometimes you have to use momentum
The more 4WDing you do, the more you learn when to use momentum, and when to back off. With our Reconn R2 off road, there are times where I’ll give the vehicle a bit more speed to get up an obstacle with the trailer on, knowing that if it doesn’t get up first time we’ll be backing down for another try, or risking wheels bouncing and scrabbling to make the final climb.
I hate seeing front wheels jumping around on a 4WD as its so easy for it to find traction in a split second and a CV or axle to snap. Of course, you have to be sensible with the momentum, and use it when appropriate, and never beyond that.
Tyre pressures should be adjusted on both the tow vehicle and the trailer
Anyone who’s taken their vehicle off road more than a few times should know that tyre pressures are hugely critical. I’ve often said they are the biggest change you can make to your 4WD for different terrains, and you should be reducing them once you are off the blacktop.
However, know that the tyre pressures on your trailer are equally important, even if they aren’t doing any of the driving. Lowering the tyre pressures down will reduce your chance of punctures on some terrains, and if you need flotation it will make a huge difference.
The perfect example of this is a Jetski and trailer, which is not overly heavy, and runs the tiniest cheese cutter tyres that you can get. Time and time again I see 4WD’s driving onto a beach with a Jetski trailer behind them, with the tyres not deflated at all.
This makes the tyres dig in, and sometimes to the point where they just drag and don’t rotate at all. A tiny amount of weight on a trailer like this can bring a very capable 4WD to a stop in a matter of seconds on a soft beach, and its always frustrating to watch.
Sometimes you can power through it, but you do it at the expense of your 4WD; giving it an absolute hiding in place of stopping and letting some air out makes zero sense to me.
Consider your turning circle
Towing a trailer means you have to watch the trailer behind you with a good eye. Trailers typically tend to cut the corner a little, which means you need to be very aware of the turning circle on your 4WD, and your trailer. The longer the trailer, the more likely it is to cut the corner and on tight tracks that means you need to give a wide berth when turning, so the trailer doesn’t hit a log, or rock, or tree that sticks out on the edge.
Sometimes you have no choice but to push your 4WD or trailer into the scrub a bit to make the corner, but with a bit of care you can pick the best line possible.
Do you have suitable trailer tyres?
If you want to take a trailer off road, you should be ensuring you have tyres that are suitable. Yes, the run of the mill Dunlop and Bridgestone tyres that come with a 4WD off the factory floor will work, but they are susceptible to punctures and will not take a huge amount of punishment on a nasty 4WD track.
As a minimum, you should have light truck tyres, with all terrains preferable, or mud terrains if you are so inclined. Trailers don’t do any drive, so they don’t need a huge amount of traction. The exception is in mud, where the trailer is more likely to stay on track than slip where you don’t want it to go.
Generally the heavier duty the trailer (all terrains and then mud terrains) the better puncture resistance you get, and it can be worth getting some really heavy duty tyres for your trailer purely from this perspective.4
We’ve just gone to Toyo RT tyres on our Reconn R2 (and will probably be getting them on our Dmax too), because they aren’t quite a muddy, but still have great puncture resistance, and can be lowered nicely without damaging the tyre compound.
Are your spares interchangeable?
Depending on where you are going, it can be helpful to have wheels and tyres that are interchangeable between the vehicle and the trailer. They don’t have to fit perfectly, but at least having the ability to swap them in an emergency is handy.
Our Dmax wheels fit on our camper trailer, and whilst they might not be load rated to the correct weight (I can’t find a load rating), they would work in an emergency. Likewise, the camper wheels fit on our Dmax (same stud pattern and exact size), and despite the fact that they’d stick way outside of our guards, we can use them as needed.
That effectively gives you two spares from the get go, and more if you are prepared to leave your camper to get new tyres.
Wheel track differences
In an ideal world, having a trailer with the same wheel track as your 4WD is what you want. It’s usually not the end of the world, and its not something too many people worry about, but on a soft sand having your trailer follow exactly where your 4WD is going helps considerably.
Do you need an automatic transmission cooler?
If you are towing something off road with a 4WD that runs an automatic gearbox, you should at the very least be monitoring the transmission temperatures, and fitting a transmission cooler if they are getting warm.
Some vehicles have much better automatic cooling than others from the factory, and some will overheat without even towing anything. I’ve had our Dmax hit 110 degrees on the beach not towing anything, in high range without a transmission cooler.
So, lets start with the basics; get an OBD2 reader and see what your temperatures are running at, and if they are often hitting 100 degrees, you should be getting an aftermarket transmission cooler to help the automatic gearbox stay cool, and not cook itself. These are hugely expensive, virtually impossible to repair on the side of the road and not something you can bush fix to get you home.
Entry and exit angles
You’re probably pretty familiar with how steep of an angle you can go into, and out of with your 4WD. If you run a bull bar, this is often the first thing to hit, and its usually your tow bar on the rear. However, when you are towing a trailer you have two new entry and exit angles; that of the trailer.
If you have a long trailer with only single axles your entry and exit angles can be quite bad, and whilst your 4WD might make it through the obstacle, what’s stopping your trailer from getting caught and doing damage?
The entry angle on the trailer is directly related to the tow bar of your 4WD, and often the thread of your hitch will be the first thing to hit, but then you can drag your drawbar and the front part of the trailer through and do significant damage.
On the rear, if you have a lot of overhang and it doesn’t cut away, you’ll smash the back of your trailer, and when you’re mid way through an obstacle it’s a bad time to realise you don’t have the clearance you need.
You can hugely help your entry and exit angles by slowing down, which reduces wheel travel due to bounce, and can maximise your entry and exit angles. I was guilty of this recently on a trip in the Pilbara, where we came down the steepest hill I’ve ever done in our Dmax and Reconn together.
At the other end it went back up again fairly quickly, forcing the camper and car together. The Dmax tow hitch just scraped the rocks at the bottom, and thinking I was clear I let my foot off the brakes and gave it a bit to exit.
The car crawled out just fine, but the camper bounced on the last descent and it came down fairly hard on the rear left with a bang.
Fortunately it only snapped the bottom part of the plastic handle for our rear left stabiliser leg, but it could have been avoided by going a bit slower for the last part (I basically forgot about the rear of the van). Our Reconn R2 has a pretty great exit angle, and there’d be a heap of other campers that would fair much less well than we did, but it was still a learning curve for me.
At this point, its worth mentioning that you need to be aware of the articulation limits of your trailer. There’s a whole range of different tow hitch types, and a 50mm tow ball is about as low performing as you can get.
Watch the wiring and chains
One thing a lot of people forget about when towing a trailer off road is the wiring that goes from your vehicle to the trailer. In most cases this is a lead for the Anderson plug, and your normal trailer wiring. If this is too long, it can easily get snared on something off road and get ripped out, or damaged.
Asides from being a pain in the backside, it can actually be a time consuming and frustrating fix (assuming you know what you are doing), so make sure they are out of the way. We’ve used light weight tie wire before to secure it near the hitch with enough movement to turn and articulate as needed, but not so much that it flaps around in the breeze.
You’ll hear your towing chains drag and knock about quite regularly, and most of the time this is of no concern, but remember that they are there, and they will also pick up anything that you drive into! They need to be as short as possible, and remember you should always cross your chains!
Do you need towing mirrors?
You need to be able to see your trailer, and well. By law, if your trailer is wider than your vehicles mirrors, you need to have towing mirrors, but they are just as important off road as well. I’ve heard a few people mention that even if they didn’t need the towing mirrors, they were greatly appreciated when driving off road.
How’s your reversing skills?
I’ve done a reasonable amount of reversing in my time, and can do it OK, but there are a lot of people who are much better than me. If you plan on towing anything you should be able to back well, and its far more important when you are off road.
You will come to dead ends, or have to turn around on single lane tracks, or reverse to take a second punt at something and if you don’t know how to reverse you are going to learn really quickly.
Do you have a good spotter?
A spotter is hugely valuable when you are towing something off road, and having a person who understands 4WD’s, flex, angles and what is likely to happen is invaluable.
Reverse cameras on the trailer are worth their weight in gold. The alternative is to stop and hop out from time to time, but having someone who you can confidently rely on directing your wheels is so useful off road.
Sarah’s getting better at this, but there are still many times where I get out because she’s not confident in what’s happening, or more often than not I have no idea what she’s trying to communicate (which isn’t always her fault!).
Final thoughts
Towing a trailer off road can be a heap of fun, and being able to climb into something dedicated for staying off grid at the end of each day is nothing short of amazing. Often a trailer allows you to have a pre set up bed, warmth, a hot shower, plenty of water on tap and so much more, and that’s pretty awesome.
Stick within your limits, drive where you are comfortable and have a good time; you’ll pick it up over time and as they say, practice makes perfect!
