15 things you probably don’t know about your 4WD

There’s a lot to learn about 4WDing. Whether you are new to the scene, or you’ve been exploring this magic country for many years, you can still pick up something new.

We’ve actually written a post covering 42 things you must know about 4WDing. However, in this post, we look at 15 things that you may not know about your 4WD. 

Reflections at Running Waters
How much do you really know about your 4WD?

Your speedo is probably not accurate

You’d expect your speedometer, odometer and trip meter to be on the money, right? The truth is, even a brand spanking new 4WD is allowed to have some speedometer error. At 100km/h it can be up to as much as 10km/h, which makes a substantial difference.

However, with 4WD’s, the most common way to alter your speedo readings is to fit different size tyres. Usually, bigger size tyres are chosen, and this will make your speedometer read lower than you are actually going.

If you’ve gone up a few sizes on tyres, your speedo will often be close to accurate, or it may read a little low. If you go up more than a few sizes, your speedo could be out by as much as 20%. If you are keen on knowing more, have a read of Fitting Bigger Tyres to your 4WD.

It pays to get a GPS, and check the difference. You can do this while sitting at a constant speed, but the most accurate way is to log 100km on both your trip metre and a GPS, and then compare. Our 80 Series Land Cruiser is out by just under 5%, running 50mm bigger tyres.

A basic GPS will allow you to check your speedometer

This is important, as you don’t want to pick up a new 4WD (even if its just new to you), and get done for speeding because you didn’t know the speedo was reading wrong! If it does read incorrectly, there are a number of ways you can get it fixed without changing your tyre size.

One of the side effects of changing tyre size is that your fuel economy calculations need to be done differently. Find out how to accurately work out your fuel economy.

Bigger 4WD Tyres
If you are running bigger tyres, your speedo is probably out

How old are your tyres?

Any form of rubber will perish over time. This is made worse when its subject to the abuse a 4WD tyre gets, but as your tyres age they will perform worse.

Every tyre in Australia has a 4 digit number stamped inside a little box on the sidewall, which tells you the manufacturing date of your tyre. If you want to know more, have a read of this – How to tell the age of your 4WD Tyres.

According to the tyre guru’s, once your tyres get to around the 5 year mark, they are considered old, and you should be looking at replacing them.

Tyre age and deflection
How old are your tyres?

Something to bear in mind is that your new tyres could already be up to a year or two old when you get them, depending on how long the tyre store has had them. If you don’t rack the kays up, its easy to hit the 5 year mark and still have a tyre that looks perfectly good.

I’m not saying the moment your tyres hit 5 years old they are going to fall apart, but its an early warning sign to pay more attention to them. Look for any signs of perishing, including cracks and worn sections. The last thing you want is to have a blow out at speed!

Tyre age stamp
Look for the two numbers; this shows the 49th week of 2011

It may not be legally modified

There’s nothing nicer than a 4WD running a big, quality suspension setup and huge muddies. They look tough as, idle through huge ruts and are a heap of fun to drive. The thing is though, most of them are not legally modified!

Big tyres on a Jeep
Is your vehicle legal?

The consequences of driving a vehicle that has illegal modifications go much further than just getting a yellow sticker. You can be liable in the case of an accident, and by law your insurance company does not have to cover you.

If you’ve changed your tyre size, suspension, wheel track, brakes, body or chassis, you’ll want to have a read of this; Is your 4WD legal?

As it turns out, there are some weird and random things that will make your 4WD unroadworthy. You can read more here; 32 ways to make your 4WD illegal.

4WD roll over
Should the worst happen, are you covered?

Your factory hooks are not rated for recoveries

You will get bogged in your 4WD, eventually. It happens to everyone, and its just part of the fun. What’s not fun though, is hearing about someone every couple of years in Australia who gets killed by a 4WD recovery that has gone wrong.

You put a heap of stress on lots of different components when recovering a 4WD using a winch or snatch strap, and you can very easily kill someone when it isn’t done correctly. The ‘hooks’ that come with your 4WD from factory are not rated to be recovered off. Before you head off road, you should get a decent set of front and rear Rated recovery points, and have them mounted correctly to the chassis with grade 8.8 bolts.

Even then, use a bridle where possible, and a blanket, dampener or towel over the recovery strap so if it does go pear shaped no one gets wiped out by it.

ARB Bull bar recovery points
Do you have rated recovery points?

What’s your Payload?

It’s scary to see some 4WD’s on the road, loaded up with more gear than you can poke a stick at. If you don’t know already, head over to Redbook, select your vehicle and under dimensions, there’s a figure given for your Pay load. This is the legal amount of weight your 4WD can legally carry. It’s important to know that the weight on your tow ball comes out of this too. Want to know more? Check out the post we wrote on Tow Ball Mass.

Tow ball weight
Tow ball weight can add up real fast

At the very least, take the time to write down the weight of everything on your car, including passengers, extra fuel, water, modifications etc. I guarantee you will be very close to the payload when heading off on a trip away.

If you are over the given pay load, you are putting excess strain on the vehicle, may not be covered by insurance in the event of an accident and could be fined badly if the authorities decide to weigh your vehicle. If you want to know more, have a read of this – What does your 4WD weigh?

Weighing the Dmax
What does your vehicle actually weigh?

What size lift kit are you running?

One of the more challenging things to do when you get a 4WD that is new to you is to find out what sort of lift kit it is running. Over time, even stiff springs will sag, and it becomes very difficult to know whether you are running a 2″, 3″, 4″ or something else.

So, what can you do to identify the lift you have? Firstly, look for blocks between the chassis and the body. Obviously they aren’t going to shrink, and if you have 50mm blocks then your vehicle has been raised by 50mm using a ‘body lift’.

50mm body lift
A body lift picks the vehicles body up and leaves the chassis in the same spot

From there, you have a few options:

The easiest is to ring your vehicles manufacturer, and ask them for a measurement to identify it. They should be able to give you this, but remember to give the right information, as they vary regularly between different years and models.

Beyond that, forums that are set up which are dedicated around specific model vehicles are a gold mine. On most of them, you should be able to tell you the measurement between the inner guard and centre of your hubs for different lift kits.

Remember that over time springs will sag, and a vehicle with an old 4 inch lift may be lower than one with a new 2 inch lift.

Lift kit in a 4WD
What size lift kit are you running?

Tow balls are not suitable recovery points

If you are new to the game, one thing you absolutely must not do when 4WDing is use the tow ball as a recovery point. Yep, its easy to drop a strap over the tow ball and take off, but these are not designed for huge amounts of energy to be applied within a split second.

Tow ball 4WD Recovery
Tow Balls are not safe for 4WD recoveries!

They will shear, and having a steel ball hurling through the air faster than you can see (usually towards another vehicle or person) is the last thing you want to do. They might look strong, but they most certainly are not.

Want to know more? Check out our latest post; Tow Balls in 4WD Recoveries can kill you.

Weight behind the rear axle can be dangerous

We covered payload earlier in the post, but you’d be mad to take a chunk of that weight and have it sitting behind your rear wheels. Do yourself a search on google, for bent 4WD chassis. Scary stuff. Is your dual cab at risk of a bent chassis?

You know what most have in common? Either they were overloaded, or they had the weight positioned too far back. I see it all the time; a badly bent, new Mitsubishi Triton dual cab, which had a heavy rear bar mounted, along with a spare tyre on one side and 4 jerry cans of fuel/water on the other side.

Dmax canopy
Too much weight over the rear can be a huge issue

Add it up; Rear Bar 50kg, tyre and swing arm 30kg, second swing arm and 80L of fluid, and you are looking at about 180kg right at the back of your chassis. Hit even a small bump, and what do you think is going to happen?

If you are going to carry heavy weight, make sure its positioned either in front of the rear axle, or on top of the axle. The further back you put it, the more stress its going to put on the last third of your chassis.

Isuzu Dmax and Reconn R2
How much weight do you have behind the rear axles?

Your insurance company may not cover you everywhere

There’s a lot of insurance companies in Australia that offer cover to 4WD vehicles. The thing is though, they are not all equal. Some insurance companies treat your 4WD as if it is the same as an ordinary car, and their level of cover may not suit your requirements.

When you take out 4WD insurance, be sure to ask where you are covered in Australia. Some companies will not cover you for driving on gravel, non-gazetted road, private property or beaches.

White Gum Farm 4WD Park
Are you covered at a 4WD Park?

4WD insurance is a very important part of owning a 4WD; if you want to know more about it, have a read of this – What to look for in 4WD insurance.

Our 80 at Lancelin
Are you covered in the dunes?

You may not be able to tow the maximum towing capacity

The number of heavy trailers being towed within Australia has gone up significantly in the last few years. Whether its a big boat, caravan or car trailer, there are very strict regulations on what you can tow.

Your 4WD will come with a maximum towing capacity, which you must not exceed. However, manufacturers are getting very sneaky and unethical, and are advertising maximum towing capacities that you would only be able to use under very unlikely situations. If you want an easy to understand guide, check this out – A simple towing capacity guide for keeping your 4WD and trailer legal.

Caravan towing
The marketed amount that a vehicle can tow is often smoke and mirrors

I won’t go into it too much in this post, but if you need to tow something heavy, you may have to ensure your 4WD is as light as possible.

As an example, think about a new Ford Ranger; if you are using the maximum towing capacity of 3500kg, you are only legally allowed to have 300kg of weight added to the 4WD itself. Take away the ball weight and just one passenger, and you are going to be overweight already.

For more information, have a read of this; Are you being misled by 4WD towing capacities?

Towing with a 4WD
What’s your towing capacity?

Tyre pressures should vary from 4WD to 4WD

Tyre pressures are one of the most important factors you have in your control when it comes to 4WDing. There’s a heap of guides out there that will tell you what tyre pressures to run, but you really need to tailor it for yourself. To start off with, check out 6 reasons tyre pressures are critical when 4WDing.

You should not be running the same tyre pressures as all of your mates; as you (more than likely) drive different vehicles. Every vehicle should have its own set of tyre pressures, based on the weight of the vehicle, tyre dimensions, terrain and speed.

Tyre deflator
Pick the right tyre pressures for your application

If you didn’t already know, your tyre pressures will go up and down as you drive, due to the temperature change of the air inside. There’s more information on that here; 4WD tyre pressures; do you check them hot or cold?

Have a look in your vehicle owners manual, which will tell you the recommended tyre pressures for certain tyres. If you do Fit bigger tyres to your 4WD, you can lower the pressures a little. As always, pay attention to the way the tyres wear. If the middle gets worn out, your pressures are too high. If the outsides get worn out, you are running them too low.

4WD Tyre pressures
Every 4WD has its own correct tyre pressures

Your roof has a weight limit

Even though a roof rack seems like a convenient place to load your gear onto, the manufacturer of your 4WD has set weight limits to what the roof of your vehicle can withstand. For most 4WD’s, its only 100kg, although there are a few that have 150kg roof load ratings. What’s your roof rack weight limit?

100kg may not seem like much, but have a think of what happens when you hit a bump off road; the forces on the roof are substantial. Overload your roof, and you end up with a high centre of gravity and you could easily damage your roof.

Roof ra
What’s your roof rack and roof rated to?

Have a think about what you have on your roof. Steel full length roof racks in my opinion, are a complete waste of money. I removed one from a mates Patrol a while back, made by one of the more reputable 4WD accessory companies, and it came in at 66kg.

That’s a ridiculous amount of weight to have on your roof racks, without even starting to store anything. You don’t have to put much more on the roof and its already overloaded!

Roof top tents are also something to be wary of; many of them weigh around the 50kg mark; that’s a lot of weight. Often I’ll come across vehicles in the bush who are carrying several jerry cans, big toolboxes and half of their kitchen on the roof. While it might be convenient, its not legal, nor safe!

Roof Rack weight
Mind the weight on your roof racks

The driver is just as important

At the end of the day, your 4WD only makes up a portion of how far it will go. Modifications and accessories can make a big difference, as does starting with a capable 4WD. That said, in my opinion, the driver behind the wheel of your 4WD makes just as much difference.

I’ve seen some very standard 4WD’s tackle tracks that have blown me away; if the driver knows the right lines and has plenty of skill they make a massive difference.

Driving in the car
How good are you behind the wheel?

Your safe wading depth might be much lower than you expect

Last week, I wrote a post about Staying out of the water without a snorkel. If you don’t know what the safe wading depth is in your 4WD, take the time to find out. This is the depth of water that you can safely drive through without doing any permanent damage to your 4WD.

4WD Safety
What’s your safe wading depth?

By permanent, I mean electrical or mechanical damage, which can be easily enough to write your vehicle off. Most vehicles have a wading depth of in between 400mm and 800mm. However, if you hit a small water crossing at speed, it doesn’t have to be that deep to cause serious damage to your 4WD.

Your vehicles manual should tell you the wading depth. If you aren’t happy with it, look at installing a snorkel.

One of the water crossings at Mundaring
Water is one way to quickly hurt your vehicle if it goes wrong

Where’s the lowest point on your 4WD?

I mentioned the quality of a driver plays a huge role in how far your 4WD will go earlier. One of the things an experienced 4WDer knows is where the low, and vulnerable parts on his/her 4WD hang down. You need to know what is likely to get hung up on your 4WD, so you can pick your lines, and reduce the chance of any damage.

Differential size
How’s your clearance?

On vehicles with solid axles, your differential pumpkin will be the lowest, along with the transfer case and sometimes the sills below your doors. Obviously, the aim of the game is to avoid hitting these, as you can do some very costly damage!

On our Isuzu Dmax, we had no choice but to run some Bash plates; they would pay for themselves in the first knock off road!

What else?

I’m sure there are stacks of things I’ve missed here. What else should you know about your 4WD before you head off road?

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