For many Western Australians, loading up the caravan and heading off on a long trip is part of the lifestyle. But as vehicles get packed with gear, water, fuel and everything in between, it’s easy to get close to, or exceed, your vehicle’s legal weight limits.
That’s where Gross Vehicle Mass (GVM) and Gross Combination Mass (GCM) upgrades come into play.
As Western Australia’s peak body for the caravan and camping industry, Caravan & Camping WA is working alongside the Department of Transport WA to help travellers better understand what’s involved and how to stay safe and compliant on the road.
GVM and GCM upgrades explained
- GVM upgrade: Increases how much weight your vehicle can legally carry, including passengers, gear and accessories.
- GCM upgrade: Increases the total combined weight of your vehicle and trailer, such as a caravan.
Both upgrades must meet WA requirements and be completed by approved providers.
What’s the difference between GVM and GCM?
Before considering an upgrade, it’s important to understand how they differ.
A GVM upgrade allows your vehicle to safely carry more weight. This often involves upgrading components like suspension, springs and shock absorbers so your vehicle can better handle the load.
A GCM upgrade increases the total combined weight of your vehicle and what you’re towing. Because of this, there are additional factors to consider beyond just suspension. Things like the chassis, engine performance, braking system and towbar all need to meet specific requirements before an upgrade can be approved – which is particularly relevant for caravanners.
In many cases, a GVM upgrade is completed first, with a GCM upgrade considered if needed.
What are the requirements in WA?
In Western Australia, GVM and GCM upgrades must meet standards introduced in 2024.
In general, this means:
- Upgrades must comply with Vehicle Technical Bulletins VTB-180A (GVM) and VTB-181A (GCM)
- Upgrades must be completed and certified by Department of Transport (DoT) approved modifiers
- All modifications must meet safety and engineering requirements before being recognised in WA
If your vehicle has already been modified interstate, it will still need to meet WA requirements before it can be licensed or recognised locally.
Can you do a GVM or GCM upgrade yourself?
No – upgrades must be completed and certified by approved professionals.
Important things to keep in mind
Before going ahead with an upgrade, it’s worth considering a few key points:
- Not all vehicles are eligible for upgrades
- A GVM upgrade does not automatically increase your towing capacity
- GCM upgrades are more complex and may only be available in certain situations.
- Modifications may affect things like vehicle wear and tear, as well as warranty and insurance coverage
- GCM upgrade can be done post-registration under DoT VTB-181A, but are limited and more complex
Final takeaway
If you’re planning to carry more or tow heavier on your next WA adventure, understanding your vehicle’s limits is an important first step.
Taking the time to get it right means:
- Safer travel
- Better performance
- Peace of mind on the road
And ultimately, that’s what makes for a more enjoyable road trip.
Need more information?
For the latest requirements and FAQs, visit the Department of Transport WA website here>>
