Just because your 4WD is rated to tow 3,000kg (or more) doesn’t mean it actually can once you factor in accessories, passengers, and tow ball mass (TBM). Exceeding your Gross Vehicle Mass (GVM) or axle load limits is not only unsafe but also illegal — and could void your insurance. The good news? With proper weighing, towing accessories or suspension upgrades, you should be able to tow safely and legally.
For the purpose of this article, “Trailer” refers to a caravan, horse float, or any other trailer.
The Towing Trap Most 4WD Owners Fall Into
If you’ve bought a new 4WD, fitted it out with all the bells and whistles, and hooked up a caravan or horse float, you might assume your rig can handle its advertised towing capacity.
Here’s the catch: tow ratings don’t exist in isolation. Every accessory you add — from bull bars to fridges — eats into your payload. Then comes the tow ball mass (TBM), which also counts towards your payload. This is where many drivers get caught out.
What Exactly Is Payload?
Payload = the maximum weight your vehicle can legally carry.
This includes:
- Passengers
- Cargo (bags, tools, fridge, etc.)
- Accessories (bull bar, roof rack, tow bar, dual batteries, long-range fuel tanks)
- Tow Ball Mass (TBM)
In many popular 4WDs (Prados, Pajeros, Rangers, Hiluxes, etc.), the payload is typically 500–700kg. Sounds like a lot — until you start adding things up.
A Real-World Example
Let’s run the numbers on a common setup in Victoria:
- Bull bar: 100kg
- Roof rack: 30kg
- Tow bar: 50kg
- Two adult passengers: 150kg
- Fridge (loaded): 60kg
That’s 390kg already, before luggage or recovery gear.
Now add a caravan with a TBM of 300kg. Suddenly your total is 690kg. If your vehicle only has a 600kg payload, you’re now over your GVM.
And that’s before kids, dogs, camping chairs, or the wine you picked up in the Yarra Valley.
Why It Matters
Driving an overloaded vehicle isn’t just unsafe — it’s illegal. If you’re pulled over or have an accident:
- You could face fines.
- Your insurance claim may be denied if you’re over the limits.
- You may be found legally liable if the load contributed to an accident.
Overloading also affects:
- Braking distance
- Steering responsiveness
- Suspension wear
- Trailer/caravan sway (a leading cause of highway accidents)
What You Can Do About It
The good news is, you don’t have to ditch your trailer or travel light as a feather. There are practical steps for trailer owners:
1. Get Your Vehicle Weighed
Services like mobile caravan weighing and horse float weighing by Weigh My Ride in Victoria check:
- Suspension heights and ride height/angle
- Load distribution and balance
- Safety and suitability check of tow hitch and coupling
- GVM (Gross Vehicle Mass)
- ATM (Aggregate Trailer Mass)
- GTM (Gross Trailer Mass
- GCM (Gross Combined Mass)
- TBM (Tow Ball Mass)
- Axle loads
This gives you a real-world snapshot of where your setup stands.
2. Reconsider Your Setup
Do you need all the vehicle accessories? Sometimes less is more. Removing drawers or packing a lighter fridge can save precious kilos.
Final Thoughts
A 4WD with all the gear looks great, but without checking your weights, you could be unknowingly breaking the law every time you tow. Worse, you may be putting yourself, your passengers, and others on the road at risk.
The fix is simple: know your numbers. Book a professional weigh, adjust your setup, and make sure your rig is safe, legal, and insured.
Because the only thing worse than a ruined holiday is one that ends with fines, breakdowns, or worse.
