If your 4WD carries tools, a canopy, bull bar, winch, drawers, touring equipment or a heavy tow-ball load, it can reach its factory Gross Vehicle Mass sooner than expected.

A properly engineered GVM upgrade can increase the vehicle’s legal carrying capacity when an appropriate approved kit and certification pathway are available.

M Carter Automotive provides eligible pre-registration GVM upgrades and assesses and certifies certain post-registration GVM upgrade kits through VASS.

We work with eligible kits from Tough Dog and Superior Engineering, subject to the exact vehicle, kit approval and registration pathway.

Contact us before purchasing or installing a kit.
Every vehicle and kit combination must be assessed individually.

REQUEST A GVM UPGRADE ASSESSMENT

What Is a GVM Upgrade?

Gross Vehicle Mass, or GVM, is the maximum permitted operating mass of a vehicle when loaded. It includes the vehicle itself, occupants, fuel, accessories, tools, luggage, cargo and the tow-ball load imposed on the vehicle.

A GVM upgrade does not simply involve fitting heavier springs. It is a vehicle-rating modification that must use suitable components and follow the correct approval and certification pathway. Depending on the vehicle and approved kit, the upgrade may include replacement springs, shock absorbers and other specified components.

The upgraded vehicle must continue to satisfy the applicable safety, handling, axle-load, wheel and tyre requirements.

When Might You Need a GVM Upgrade?

You may need to investigate a GVM upgrade if your 4WD is fitted with or regularly carries:

• A service body, canopy or tool storage system
• Bull bar, winch, underbody protection or auxiliary batteries
• Drawers, fridge, long-range fuel tank or touring equipment
• Roof racks, rooftop tent or other permanent accessories
• Passengers and luggage for extended travel
• A caravan or trailer that places additional tow-ball load on the vehicle

The only reliable way to understand your available payload is to weigh the vehicle in its actual operating configuration and compare the measured axle loads and total mass with its ratings.

Pre-Registration GVM Upgrades

A pre-registration GVM upgrade is completed before a new vehicle is first registered. Where an appropriate approved kit and pathway are available, the specified components are installed and the required compliance documentation is completed before registration.

Pre-registration upgrades can be a practical option for a new work or touring vehicle that will be fitted with significant accessories. The proposed build should be planned before the vehicle and kit are ordered so the finished configuration can be assessed as a complete system.

Post-Registration GVM Upgrades and VASS Certification

A vehicle that has already been registered requires the Victorian post-registration approval pathway. M Carter Automotive can assess and certify certain eligible GVM upgrade kits through VASS.

The process may include:

1. Reviewing the vehicle, current modifications and intended use
2. Confirming that the proposed kit and vehicle combination is eligible
3. Checking kit identification and supporting technical documentation
4. Inspecting the installation and specified components
5. Confirming relevant axle, wheel, tyre, suspension and vehicle-rating requirements
6. Completing the applicable VASS certification documentation when the vehicle complies

When a modified vehicle is accepted and certified by an authorised VASS signatory, the documentation may include a VASS approval certificate and blue modification plate. Additional VicRoads steps may apply to update the vehicle’s registration record.

Tough Dog and Superior Engineering GVM Upgrade Kits

M Carter Automotive works with selected GVM upgrade kits from Tough Dog and Superior Engineering. Both manufacturers offer vehicle-specific products, but the brand name alone does not make every suspension kit a certifiable GVM upgrade.

Before a kit is accepted, we confirm:

• The manufacturer and exact kit part number
• The vehicle make, model, variant and build date
• Whether the approval applies before or after first registration
• The nominated GVM and applicable axle ratings
• The required wheels, tyres and supporting components
• The installation and certification requirements for that kit

Please contact us with your vehicle details before ordering a Tough Dog or Superior Engineering kit.

Why the Kit Must Be Confirmed Before Installation

Not every suspension kit is a GVM upgrade kit, and not every advertised kit can be certified for every vehicle. Certification depends on the exact vehicle, registration status, kit approval, wheel and tyre ratings, existing modifications and correct installation of all specified components.

Contacting us before purchasing a kit avoids wasted expense and helps establish the correct certification pathway from the beginning.

GVM Does Not Automatically Increase Every Other Rating

A GVM upgrade changes the approved maximum vehicle mass only within the scope of the relevant approval. It does not automatically increase the manufacturer’s Gross Combined Mass, towing capacity, tow-bar rating or individual component ratings.

The vehicle must still remain within every applicable rating, including front and rear axle limits, wheel and tyre capacities, towing limits and Gross Combined Mass.

GVM Upgrade Assessments in Alphington

M Carter Automotive is located at 166 Grange Road, Alphington. We provide practical advice for work vehicles, towing vehicles and touring 4WDs, with pre-registration services and VASS assessment and certification available for eligible post-registration kits.

To determine the correct pathway, please provide:

• Vehicle make, model, year and variant
• VIN and current registration status
• Current accessories and modifications
• Intended accessories, load and towing use
• Proposed kit manufacturer and part number, if already selected
• Current vehicle or axle weights, if available

REQUEST A GVM UPGRADE ASSESSMENT

Frequently Asked Questions

Can any 4WD receive a GVM upgrade?

No. Eligibility depends on the exact vehicle, the available approved kit or engineering evidence, its registration status and the condition and configuration of the vehicle.

Should I buy the GVM kit before contacting you?

No. Contact M Carter Automotive first so the vehicle and proposed kit can be checked for suitability and the correct approval pathway can be confirmed.

Is heavier suspension alone a legal GVM upgrade?

No. Suspension components may form part of an approved upgrade, but fitting heavier springs or shock absorbers alone does not change the vehicle’s legal GVM.

Can you certify a vehicle that is already registered?

M Carter Automotive can assess and certify certain eligible post-registration GVM upgrade kits through VASS. The vehicle and kit documentation must be reviewed before acceptance.

Which GVM upgrade brands do you work with?

We work with selected Tough Dog and Superior Engineering GVM upgrade kits. Eligibility depends on the exact vehicle, kit part number, supporting approval and whether the upgrade is being completed before or after first registration.

Does a GVM upgrade increase towing capacity or GCM?

Not automatically. Towing capacity, tow-bar rating, Gross Combined Mass and axle limits remain separate ratings unless they are specifically addressed by an applicable approval.