Heavy vehicle certification - VSB6 Compliance- Australia wide

Full engineering certification for heavy vehicle modifications, GVM upgrades, repair plans to VSB6 standard - trucks, buses and heavy trailers.

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Jump to FAQs GVM Upgrade Finder

Prime mover damage to chassis rails assessment

Related services

ATM upgrades →

Heavy vehicle engineering (VSB6) →

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From the blog

What is a GVM upgrade? →

Understanding VSB6 →

Understanding the vehicle certification process→

Ready to upgrade?

Servicing Northern Territory, Queensland, Western Australia, South Australia registered vehicles Australia wide

Frequently asked questions

How long does the engineering process take?

Timeframes vary depending on the complexity of the project and the documentation required. Straightforward inspections may be completed quickly, while more complex engineering assessments or custom modifications require additional analysis and documentation. Furthermore, difference in wait times are dependent on the regulatory body providing the approval. Each State and Territory has its own body, as does the federal system.

How much does a GVM upgrade cost?

Total cost = engineering certification +shop install. Engineering certification starts anywhere between $1,990 and $5,990 depending on your vehicle type, complexity, and whether there are type approvals available in your state or territory. Shop installs vary from $2,500 to beyond $50,000 depending again on type of vehicle and modifications required/desired. Call us to discuss.

Is your vehicle suitable for a GVM upgrade?

Possibly. It depends on the vehicle model, chassis, suspension, axle limits, brakes, tyres, and intended use. We review those factors to confirm whether a GVM upgrade is suitable and what certification is needed. See our GVM Upgrade Finder tool or call us to discuss.

How do GVM and GCM differ on your vehicle?

GVM is the maximum weight your vehicle can carry when loaded. GCM is the maximum combined weight of the tow vehicle and trailer together. A GVM upgrade may not change GCM. We can help you work out what applies to your setup.

Will a GVM upgrade increase my towing capacity?

Not necessarily. A GVM upgrade increases the maximum allowable weight of the vehicle itself, but it does not automatically increase towing capacity or Gross Combination Mass (GCM). Every vehicle has specific limitations, and these should be considered when planning modifications or towing heavier loads.

What information do I need to get a quote?

To provide accurate advice, we'll generally need:Vehicle make, model and yearVIN (if available)Registration state or territoryDetails of any existing or planned modificationsIntended use (touring, towing, commercial, etc.)Providing this information upfront helps us identify the most suitable engineering pathway and provide an accurate quotation.

What's the difference between pre-registration and post-registration GVM upgrades?

Pre-registration GVM upgrades are done before the vehicle is registered and are often part of a Second Stage of Manufacture (SSM). Post-registration upgrades are performed on already registered vehicles and may have different compliance requirements.

How much can I increase my GVM?

The amount you can increase your GVM depends on your vehicle's make, model, and structural capacity. A licensed engineer can assess your vehicle and determine the maximum allowable GVM.

Can I get a GVM upgrade after my vehicle is registered?

Yes, GVM upgrades can be performed on registered vehicles. However, the process and requirements may vary depending on your state or territory.

Does a GVM upgrade increase my GCM?

No, a GVM upgrade does not automatically increase your GCM (Gross Combination Mass). GCM is determined by the vehicle manufacturer and may require separate certification.

What is a GVM upgrade?

A GVM (Gross Vehicle Mass) upgrade increases the maximum allowable weight your vehicle can carry when fully loaded. This is achieved by modifying components such as suspension, brakes, and axles to meet higher load requirements.

Does a GVM upgrade affect insurance?

Yes, a GVM upgrade can affect your insurance. It's important to inform your insurer about the modification to ensure your policy remains valid.

Is a GVM upgrade legal in Australia?

Yes, GVM upgrades are legal in Australia, provided they comply with the Australian Design Rules (ADRs) and state or territory regulations. Certification by a licensed engineer is typically required.

Can I reverse a GVM upgrade?

Yes, a GVM upgrade can be reversed, but it requires re-certification to ensure the vehicle complies with its original specifications.

Does it affect warranty?

A GVM upgrade may affect your vehicle's warranty, especially if the modifications are not approved by the manufacturer. Check with your dealer or manufacturer for details.

Does it affect resale value?

A GVM upgrade can affect resale value positively or negatively, depending on the buyer's needs. Some buyers may value the increased capacity, while others may prefer an unmodified vehicle.

What modifications are normally required?

Common modifications for a GVM upgrade include upgrading the suspension, brakes, and axles to handle increased loads. Additional components may also be modified depending on the vehicle.

What is heavy vehicle certification?

Heavy vehicle certification is the engineering sign-off required whenever a truck, bus, or heavy trailer is modified — a chassis change, body/tray replacement, coupling change, or suspension upgrade — under the National Code of Practice (VSB6). It confirms the modified vehicle still meets national safety and design standards. A heavy vehicle is defined > 4.5 tonnes.

Our certification covers assessment, design verification, and the compliance plate/paperwork needed to keep your heavy vehicle legally registered and operating after modification. We service heavy vehicles Australia wide and with our national network of inspectors, we can come to you.

Without VSB6 certification, a modified heavy vehicle is not road-legal, may be refused registration, and could be uninsured in the event of a claim.

Heavy Vehicles - Read our full guide on VSB6 compliance →

Our process

Assessment

We review your vehicle, intended load, modification scope, and applicable VSB6 requirements.

Engineering

Engineering review of the modification against national heavy vehicle standards.

Inspection

The vehicle is inspected, weighed and tested to confirm it meets the required standard.

Certification

We issue engineering compliance certification and plates needed for registration.

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What is a GVM upgrade? →

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Understanding the vehicle certification process→

Need certification?

Servicing vehicles Australia wide

Call now

Get it certified right, the first time.

Contact KME Vehicle Engineering

Independent engineering you can trust

KME provides independent engineering advice and certification. We recommend solutions that are legal, practical and suited to what your vehicle is needed for.

Fully compliant

ADR and state regulations
Engineering certification
National experience

Vehicle-Specific Advice

Touring vehicles
Work utes
Fleet vehicles
Heavy vehicles

Australia wide

Remote assessments
Dealer support
Interstate certification
National approvals

Experienced

15+ years of engineering
Practical advice
Fast turnaround
Real technical knowledge

Starting price

Ford

F450

8,000

13,500

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

Ford

F350

4,490

7,000

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

Ford

F250

4,490

6,000

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

Cheverolet

Silverado 4500

8,000

10,400

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

Cheverolet

Silverado 3500

4,490

6,700

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

Cheverolet

Silverado 2500

4,490

6,000

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

RAM

RAM 4500

4,490

8,700

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

RAM

RAM 3500

4,490

6,011

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

RAM

RAM 2500

4,490

6,000

Starting GVM (kg)

Available GVM upgrade (kg)

Model

Make

Daly was a pleasure to work with and has a wealth of knowledge, which he is happy to share. He is able to explain ADR requirements in simple terms and is more than happy to help customers understand the pathway to certification.

Steve P.

Very professional and efficient service. Daly is very knowledgeable and obliging and a pleasure to deal with.

Duncan T.

I can't complain about getting my GVM upgrade the same day I asked and paid!! Too good to be true. Amazing service.

Jamie L.

Example projects

Northern Territory

VSB6 Approvals to Medium Truck: D3, E3, F1, G4 & M1

Heavy vehicle, Vehicle Modification

Medium truck — VSB6 modification approvals covering D3 (non-standard rear wheels), E3 (non-standard front wheel), F1 (suspension substitution), G4 (brake system certification) and M1 (fuel system alterations).

Northern Territory

Prime Mover Damage to Chassis Rails Assessment

Heavy vehicle, Repair

Prime mover chassis rail damage assessment — structural inspection and engineering evaluation of chassis rail damage, with recommendations and certification for repair to restore compliance

South Australia

RAM3500 to 6.2t

GVM, Heavy vehicle

Dodge RAM 3500 — GVM upgrade to 6.1t with a 3,500kg rear axle rating, certified under VSB6 (D3, E3, F1, G4, J1, M1, P1, S1, S2) with full engineering evidence package covering suspension substitution, brake system re-certification, and ADR compliance across all applicable rules.

Queensland

F350 Upgrade to 6.1t

GVM, Heavy vehicle

Chassis, suspension and brake upgrade to support a fully touring-fitted setup.

Frequently asked questions

Can a truck's GVM be increased?

Yes, many heavy vehicles can have their Gross Vehicle Mass (GVM) increased, provided the vehicle is capable of safely carrying the additional load and all applicable regulatory requirements are met.A GVM upgrade may involve changes to the suspension, axles, tyres, wheels, braking system or other components. Every upgrade requires an engineering assessment to ensure the vehicle continues to comply with the relevant Australian Design Rules (ADRs) and the National Heavy Vehicle Standards.Generally for any given truck you can upgrade the GVM by between 300kg and 2500kg with no physical changes to the truck. KME Vehicle Engineering can assess whether your truck is suitable for a GVM upgrade and provide engineering certification where applicable.

Can a truck's GVM be de-rated?

Yes. A truck can often be de-rated to a lower Gross Vehicle Mass (GVM) where there is an operational or licensing requirement to do so.Common reasons for de-rating include:Registration in a different vehicle classLicensing requirementsOperating under specific access conditionsFleet management requirementsThe process varies depending on the vehicle manufacturer, state or territory requirements and whether the vehicle has previously been modified. We can advise on the most appropriate pathway for your vehicle.The thing to be wary of here is your reduction in payload. It doesn't make any sense to have a truck with a 100kg payload. We can help you work out what your new payload will be.

Can original GVM be restored?

In many cases, yes.If a truck has previously been de-rated from its original manufacturer's GVM, it may be possible to restore the original rating, provided the vehicle still meets the manufacturer's specifications and all required engineering and regulatory requirements can be satisfied.The process will depend on how the vehicle was originally de-rated and whether any components have since been modified or replaced.We regularly assist clients with assessing vehicles that have been de-rated and determining whether restoration to the original GVM is possible.

Can axle ratings be increased?

Sometimes.An axle rating can only be increased where there is sufficient engineering evidence to demonstrate that the complete axle system—including the axle housing, suspension, wheels, tyres, bearings, brakes and associated components—can safely support the higher load.Increasing an axle rating is significantly more complex than fitting heavier springs and generally requires detailed engineering analysis and supporting technical evidence.We can assess your vehicle and determine whether an axle rating increase is feasible and what modifications may be required.

Do you certify body changes?

Yes.We provide engineering certification for a wide range of heavy vehicle body modifications, including:Tray bodiesService bodiesTipper bodiesWater tanksEquipment bodiesMotorhome conversionsSpecial purpose vehiclesEach modification is assessed to ensure it complies with the relevant Australian Design Rules, Heavy Vehicle National Law (where applicable), and engineering requirements.

Can you certify crane installations?

Yes.Vehicle-mounted cranes must be installed in accordance with the manufacturer's requirements and may require engineering certification to ensure the vehicle remains safe and compliant.Our assessment may include:Chassis loadingAxle loadsStabilityMounting arrangementsStructural adequacyVehicle mass distributionCompliance with applicable standardsWe can work with body builders, fleet operators and crane installers throughout the design and certification process.

Do heavy vehicle modifications require VSB 6 approval?

Yes they do. Many heavy vehicle modifications are assessed against the National Code of Practice for Heavy Vehicle Modifications (VSB 6).Whether certification is required depends on the type of modification being performed. Examples include:GVM upgradesChassis modificationsWheelbase alterationsBody changesSuspension modificationsTow couplingsSeating changesEquipment installationsNot every modification requires engineering approval, but it is important to obtain advice before commencing any work. Modifications completed without the appropriate engineering certification may create registration, insurance and compliance issues.KME Vehicle Engineering can advise whether your proposed modification falls within VSB 6 requirements and guide you through the certification process.