Most overland builds don’t fail because of one bad part. They fail slowly, because the vehicle is carrying more weight than it was designed for, in the wrong places. Springs sag, brakes fade on long descents, tyres run hot and the chassis takes a beating on corrugations. Getting the weight right is the least exciting part of a build and probably the most important.
Know your numbers
Every vehicle has a few weight limits on the compliance plate or in the owner’s manual. These are the ones that matter:
- Kerb weight: the vehicle empty, with fluids and usually a full tank of fuel.
- GVWR / GVM: the maximum the vehicle can legally weigh when loaded, including passengers, gear and accessories.
- Payload: the difference between the two. This is your real budget.
- Axle ratings (GAWR): the maximum load on the front and rear axles individually.
- Roof load rating: often given as a dynamic (driving) figure and a higher static (parked) figure.
The axle ratings are the ones people forget. It’s entirely possible to be under your total GVWR and still overload the rear axle, because most of the gear in an overland build ends up in the back.
Accessories eat payload fast
Bull bar, winch, rear bar, dual batteries, drawers, a fridge, a roof rack and a rooftop tent can easily add a few hundred kilograms before you’ve packed food, water or people. Add tow ball weight if you’re pulling a trailer, because that counts against your payload and mostly lands on the rear axle. Write down the weight of every accessory before you buy it, not after.
Where the weight goes matters as much as how much
Keep heavy things low and between the axles
Water, fuel, tools and recovery gear are the densest things you carry. The lower and more central they sit, the less they raise the centre of gravity and the less they upset the balance between the front and rear axles. A drawer system or a cargo barrier that keeps heavy items forward and low is better than piling everything at the tailgate.
Watch the rear overhang
Weight hung behind the rear axle, like a swing-away wheel carrier with jerry cans or a heavy rear bar, works like a lever. It loads the rear axle with more than its own weight and takes some load off the front axle, which can make steering and braking feel lighter on rough or loose surfaces.
Be careful with the roof
The roof is the worst place for heavy items. Weight up there raises the centre of gravity, increases body roll and makes the vehicle less stable on side slopes and in sudden manoeuvres. Keep the roof for light, bulky gear like a tent, awning or empty containers, and check your vehicle’s dynamic roof load rating, which is often lower than people expect.
Wheels and tyres
Bigger, heavier tyres and wheels add unsprung weight, the weight that the suspension has to control. That can make the ride harsher, lengthen braking distances and increase fuel use. Choose a tyre with the load rating your vehicle actually needs at its loaded weight, rather than the biggest or heaviest option. Our guide to choosing overlanding tyres covers load ratings in more detail.
Match the suspension to the real weight
If your vehicle spends most of its life loaded, the springs need to be rated for that loaded weight, not the empty vehicle. Many aftermarket suspension makers offer springs rated for different constant loads. Fitting stronger springs doesn’t increase your legal GVWR, though, and in some places that requires a separate approved upgrade.
Weigh it
The only way to know is to weigh the vehicle fully loaded, the way you actually travel. Many public weighbridges and truck-stop scales can weigh each axle separately. Compare the results with your GVWR and axle ratings, then move or cut weight where you’re over.
Quick answers
What is the difference between GVWR and payload?
GVWR is the maximum the loaded vehicle may weigh. Payload is GVWR minus kerb weight, so it’s how much you can add in people, gear and accessories.
Is it better to carry weight on the roof or inside?
Inside, low and between the axles. Keep the roof for light, bulky items.
Do stiffer springs increase payload?
No. They can help the vehicle carry its load better, but the legal GVWR stays the same unless you get an approved upgrade where that’s available.
Featured photo: Michael Aleo on Unsplash.
