In previous articles about load carrying we’ve concentrated on talking about the things you need to make your 4WD capable of carrying more, such as a canopy, roof rack, load cover or even a tow bar so you can haul a trailer behind.
But one area we have only touched on lightly in the past has been the modifications you should do to your vehicle’s suspension if you’re going to be carrying heavy loads, or even light loads in rough territory.
There was huge controversy back when I lived in Africa about a guy who had cracked the chassis of his Isuzu double cab and wanted the vehicle replaced, and there was a long drawn-out media battle, not made any better by arrogance from the motor company concerned, or the fact that the guy who owned the Isuzu was the son of an MP.
Just by chance I got involved after I managed to find out some facts about this particular case “from the horses mouth”, so to speak.
On a totally unrelated visit I met the service manager at the dealership where the vehicle was taken when it came out of the bush and the owner discovered he had a problem.
He told me that the vehicle was not just heavily laden with camping equipment, two camping refrigerators full of freshly killed meat, and everything else you might need for a long camping expedition.
No, the worst thing was that the whole inside of the load well was covered in mud, in a pattern which suggested that the vehicle had been partially immersed.
Now, a litre of water weighs a kg. The interior of an Isuzu ute wellside is about 1.3 cu metres, or 1,300 litres. So that means that IN ADDITION to all the camping gear, canopy, rooftop tents, fridges etc there could have been as much as an extra half ton of water filling all the nooks and crannies, all at the rear of the vehicle.
Under those circumstances the rear suspension would flop right against the bump stops, so that every time the vehicle hit a bump the whole shock loading would be transferred into the chassis instead of being absorbed by the suspension.
Something had to give, and in this case it seemed like it was the chassis.
So before you go looking at ways to put more load into or onto your 4WD, you should first have a look at what it’s going to do to the suspension, and if the setup you’ve got will be able to cope.
According to Stocks, the distributor of Australian-made King Springs, there are four major reasons why springs need to be replaced
Firstly, to maintain or return the vehicle to standard height. This is most commonly undertaken when the original springs have sagged or previously fitted higher springs are no longer required.
Secondly, to raise the vehicle. This is common in 4WD vehicles for increased ground clearance, but also for heavily laden vehicles, those fitted with LPG tanks, and to compensate for heavy towing.
Third, handling. When an improvement in handling is required, performance replacement springs will substantially reduce body roll and improve a vehicle's stability.
Fourth, heavy loading. All vehicles are manufactured to a general acceptable standard and springs are no exception to this rule.
With demands for comfort a growing priority, springs rates are kept as low as possible and for this reason the original springs' ability to carry load and tow is in most cases poor.
Performance replacement springs will decrease the vehicle's ride height loss under load and improve vehicle stability when laden.
King Springs says a new generation of high tensile steel has allowed the company to improve many of its existing designs by reducing the amount of steel required in a spring, making it substantially lighter (by approximately 30 percent) and reducing the solid height, therefore increasing spring travel.
Although considerably more expensive in raw material form, King Springs says it has progressively introducing this new high stress steel to all its 4WD designs at no extra cost.
There is, of course, a wide range of suspension improvements available across the market, and other strong competitors include ARB, with suspension improvements for all purposes, as well as the much acclaimed Old Man Emu range.

OK, so you’ve ascertained that your vehicle is tough enough to cope with the load.
So what can you do to carry more?
First up, we’ve mentioned a canopy (on a ute).
There are some really well-made items out there, and it pretty much depends on “the more you pay, the more you get”.
But there are a couple of things you should look out for no matter what the price.
When you are searching for a pickup canopy, look for the ones that are versatile and which can be used for carrying larger amounts or that are made of more durable materials that are waterproof and won't rust.
You can find ones that have rear doors that flip open with the tailgate, ones that open to the side or even ones with extra opening windows for easy access.
The things to look out for are basically the same. Hinges must be strong enough to last the lifetime of the canopy, and securely attached so they can withstand high winds. When closed it must lock securely, and when the back is opened there should be gutters or other protection to ensure water doesn’t run or drip inside onto your stuff.
If you’re going to put anything on top there should be enough strength, either in the canopy itself, or in additional framing, to cater for this (though we don’t recommend too much on top as this can upset the centre of gravity).
Most of all ensure that the canopy attaches firmly to your vehicle and can’t come off.
Roof racks for station wagons should be strong enough to withstand the load you’re putting on them.
Although this is often the simplest means of expanding your vehicle’s load carrying ability, again note must be made of the fact that the centre of gravity will raise, making your vehicle more susceptible to rollover in off-road conditions.
You must also ensure your rack is securely fastened and can’t slide forward when descending or climbing a hill, or under hard braking.
Thirdly, see our intro on suspension requirements.
A simple way to carry your stuff in a ute is a hard tonneau cover. They are usually lockable, making them much more secure than the rubberised canvas versions, and they are easy to use.
Or you can look at a roof box. Again, they do raise your centre of gravity, but the upside is that the latest versions, such as those made by Mont Blanc, are themselves quite light, and they’re also streamlined and lockable.
Lastly, you can look at hooking up a trailer.  This is not ideal if you’re going to be doing a lot of off-roading, but what a lot of people do is trailer to the campsite, then leave the trailer behind with the tents etc as a secure lockup where they can store stuff such as the fridge while going off to do a bit of 4WD exploring.
Again, depending on what you’re going to be towing, ensure you’re below the legal limits for your vehicle – and you might have to check the suspension to cater for the extra load on the rear axle.