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GVM, GCM and BTC Explained

How do I get a GVM, GCM or BTC Upgrade

from GVM Central

As we pride our selves on creating tailored solution based on vehicle type and intended usage, to ensure compatibility with your 4x4, SUV or utility please contact GVM Central on 0433 464 161 for chat we will give you a quote for the best tailored solution

GVM- Gross Vehicle Mass

GVM stands for Gross Vehicle Mass. It’s the maximum weight your vehicle is legally allowed to carry once fully loaded, and it’s closely tied to your axle load limits.

For example, a standard Toyota LandCruiser 200 Series has a maximum GVM of 3,350 kg. When you start adding passengers, accessories, fuel, and gear, you’ll see just how quickly you can reach that limit.

When upgrading your vehicle’s GVM, not all kits are created equal. A proper upgrade should consider four critical areas:

1. Suspension

   • Are the springs correctly rated for the extra load?

   • Can the shock absorbers manage the weight and keep the vehicle stable, even over rough terrain?

2. Braking

   • Will the factory brakes safely stop the extra mass?

   • Can they deliver reliable stopping power within the required distance?

3. Driveline

   • Is the clutch, gearbox, engine, and differential strong enough to handle the added strain?

   • Carrying more weight means nothing if the driveline components can’t cope.

4. Axle Loads

   • Do the upgraded axle ratings allow you to distribute weight across the vehicle in a practical way?

   • GVM increases don’t mean much if axle load limits are too low.

Before investing in a kit, ask yourself: does it address all four of these points? If not, the upgrade may not deliver real-world benefits.

Axle Load Ratings

Why do axle loads matter?
They determine where the weight can actually sit on your vehicle.

Take this example of a Landcruiser 200 series

• GVM = 3,350 kg

• Rear axle rating = 1,950 kg

• Front axle rating = 1,700 kg

Even though the total GVM is 3,350 kg, you can’t just load everything on the rear. If the rear axle limit is exceeded, you’re non-compliant (and unsafe), even if the total weight is within limits and often on a 200 Series with a typical 3 tonne van behind the GVM will be close to 3,350kg but the rear axle weight will be over the maximum 1,950kg

Manufacturers like Nissan set axle ratings for vehicles such as the Y62 Patrol (rear axle rated at 2,030 kg). With engineer tested and approved components—like heavy-duty suspension arms, upgraded coil springs, and stronger components—GVM Central can legally increase that rear axle capacity to 2,400 kg.

These upgraded components are designed and tested with built-in safety margins. It’s not safe (or legal) for other companies to simply “re-rate” them without the proper engineering, especially given Australia’s harsh conditions like corrugations, off-road impacts, and long-term fatigue.

GCM – Gross Combined Mass

GCM stands for Gross Combined Mass. It’s the maximum allowable weight of your loaded vehicle plus whatever you’re towing.

Here’s a simple example:

• GVM = 3,300 kg

• BTC (braked tow capacity) = 3,500 kg

• Stated GCM = 6,800 kg

This means you can legally load your vehicle to 3,300 kg and tow 3,500 kg at the same time.

But if your vehicle has a GVM upgrade to 4,000 kg while the stated GCM remains 6,800 kg, you can’t load to the full 4,000 kg and still tow 3,500 kg. The numbers must work within the combined limit.

Not every upgrade provider offers GCM increases. Many will only increase GVM while keeping the manufacturer’s original GCM. At GVM Central, vehicles are tested against recognised standards, and GCM upgrades are being developed and engineered for a growing range of mode

BTC – Braked Tow Capacity

BTC refers to how much weight your vehicle can legally tow when using trailer brakes. It is directly linked to both GVM and GCM.

Example:

• Original GVM = 3,300 kg

• Upgraded GVM=3,800kg

• BTC = 3,500 kg

• GCM = 6,800 kg

If your vehicle is loaded to the full 3,800 kg, you can’t tow the full 3,500 kg at the same time. Instead, towing capacity reduces to 3,000 kg in that situation.

GVM Central currently provides BTC upgrade packages for select vehicles, with more models under development.

Are you wanting to become a GVM Central Partner

We are looking for professional installers with established facilities to become Authorised Installation Centres in key locations.

Drop us an email detailing your interest and we will call you back for a chat.....or call us on 0433464161

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