Heavy vehicle engineering & VSB6 certification

Engineering assessment and certification for heavy vehicle GVM and GCM upgrades, VSB 6 modifications, chassis and body changes, suspension and wheel modifications, seating, towing and other complex vehicle engineering.

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Darwin-based | Australia-wide engineering support | Light and heavy vehicle specialists

Prime mover damage to chassis rails assessment

What is heavy vehicle certification?

KME Vehicle Engineering provides engineering assessment and certification for heavy vehicle modifications, including GVM and GCM changes, chassis and body modifications, suspension and wheel changes, seating, towing systems and other complex vehicle modifications.

The applicable engineering and certification pathway depends on the vehicle category, modification type, registration jurisdiction and relevant technical requirements. VSB 6 is an important technical framework for many heavy vehicle modifications, but the administrative approval process is determined by the relevant registration authority.

Our role is to assess the proposed modification, identify the engineering evidence and inspection requirements, and prepare the applicable certification documentation where the assessment supports the modification.

Heavy Vehicles - Read our full guide on VSB6 compliance →

Isuzu NPS heavy-vehicle upgrades

KME Vehicle Engineering can assess eligible Isuzu NPS 300 and NPS 75-155 4x4 trucks for vehicle-specific GVM and GCM upgrades.

For the Isuzu NPS 300, available engineering pathways include increasing GVM from 6,000 kg to 7,500 kg and GCM from 9,500 kg to 11,000 kg.

For the Isuzu NPS 75-155, KME can assess an increase from 7,500 kg to 8,000 kg GVM and from 11,000 kg to 12,000 kg GCM. A rear-dual to super-single wheel and tyre conversion may also be assessed as a separate modification.

GVM, GCM and wheel conversions are separate engineering modifications. Eligibility depends on the specific vehicle, components, completed configuration, supporting evidence and registering jurisdiction.

View Isuzu NPS GVM and GCM options →

View a completed Isuzu NPS upgrade project →

View the Isuzu NPS 300 GVM and GCM upgrade project →

Heavy vehicle services

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KME's 4 step process

Assessment

We review the vehicle, current ratings, intended operating mass, modifications and registration jurisdiction to determine the appropriate engineering pathway.

Engineering

We assess the proposed mass increase and identify the engineering evidence, component changes and any testing required for the applicable pathway.

Inspection

The vehicle is inspected and, where required, weighed or tested against the relevant engineering and jurisdictional requirements.

Certification

Where the assessment supports the modification, KME prepares the applicable engineering certification documentation for the relevant approval pathway.

Find the right GVM upgrade pathway for your heavy vehicle

Start with your vehicle below. The finder shows heavy-vehicle GVM options KME Vehicle Engineering can assess. GCM changes are assessed separately and depend on the vehicle, proposed rating, engineering evidence and registration jurisdiction.

GVM Upgrade finder - What GVM options do you have?

Make

Model

Starting GVM weight (kg)

Available GVM upgrade (kg)

Starting Price

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Available GVM upgrade (kg)

ISUZU

NPS 300

6,000

7,500

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

ISUZU

NPS 75-155

7,500

8,000

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Ford

F450

8,000

13,500

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Ford

F350

4,490

7,000

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Ford

F250

4,490

6,000

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Chevrolet

Silverado 4500

8,000

10,400

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Chevrolet

Silverado 3500

4,490

6,700

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Chevrolet

Silverado 2500

4,490

6,000

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

RAM

RAM 4500

4,490

8,700

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

RAM

RAM 3500

4,490

6,011

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

RAM

RAM 2500

4,490

6,000

$5490

Starting GVM (kg)

Available GVM upgrade (kg)

$5490

Starting price

Found your vehicle? The next step is an engineering assessment

The GVM Upgrade Finder is a starting point only. The suitable upgrade pathway depends on the specific vehicle, current ratings, existing modifications, intended operating mass and registration jurisdiction.

KME Vehicle Engineering can assess your vehicle and confirm the engineering pathway, evidence and modifications required before you commit to an upgrade.

Request a Heavy Vehicle GVM assessment

Can’t see your vehicle or target GVM? Send us the make, model, year, VIN and current GVM and we’ll review what pathway may be available.

Request a Heavy Vehicle GVM Assessment

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

Heavy vehicle engineering in practice
KME Vehicle Engineering works across heavy vehicle GVM and GCM upgrades, VSB 6 modifications, chassis and body changes, suspension and wheel modifications, towing systems and other complex engineering. The examples below show how the engineering pathway varies by vehicle, modification scope and registration jurisdiction.

Northern Territory

Chevrolet Silverado 2500 Gooseneck Hitch Certification — NT

Towing, Heavy vehicle, Vehicle Modification

Engineering certification of a Chevrolet Silverado 2500 gooseneck tow-hitch installation in the Northern Territory under VSB 6 Section P. The vehicle-specific installation was inspected and assessed; GVM and GCM remained at their original ratings.

Western Australia

Chevrolet Silverado 2500 BDS 3-inch Lift & 5,534 kg GVM — WA

GVM, Suspension, Heavy vehicle, Vehicle Modification

Engineering certification of a Chevrolet Silverado 2500 fitted with a Fox BDS 3-inch suspension kit and 35-inch tyres, with GVM re-rated to 5,534 kg in Western Australia. Assessment included non-standard wheels and tyres, suspension, braking and towing-system checks under VSB 6.

Western Australia

Chevrolet Silverado 2500 Canopy & 5,500 kg GVM Engineering — WA

GVM, Heavy vehicle, Vehicle Modification

Engineering certification of a Chevrolet Silverado 2500 canopy/body modification together with a GVM re-rating from 5,148 kg to 5,500 kg in Western Australia. The project included vehicle-specific inspection, brake testing and ADR/VSB 6 assessment while retaining the OEM suspension and wheels.

Western Australia

Chevrolet Silverado 2500 Suspension & 5,800 kg GVM Upgrade — WA

GVM, Suspension, Heavy vehicle, Vehicle Modification

Engineering certification of a Chevrolet Silverado 2500 HD GVM upgrade to 5,800 kg in Western Australia, with Bilstein suspension components, additional rear leaf support, airbags and non-standard LT295/70R18 wheels and tyres assessed under VSB 6.

Western Australia

Chevrolet Silverado 2500 NB1 to NB2 & 5,171 kg GVM — WA

GVM, Suspension, Heavy vehicle, Vehicle Modification

Engineering certification of a Chevrolet Silverado 2500 category change from NB1 to NB2 with GVM re-rated from 4,536 kg to 5,171 kg in Western Australia. The vehicle used a Rough Country 3-inch Vertex suspension kit, 35-inch tyres and revised GVM/GCM ratings assessed under VSB 6.

Western Australia

RAM 3500 Gooseneck Hitch Certification — WA

Heavy vehicle, Vehicle Modification

Engineering certification of a 2025 RAM 3500 gooseneck coupling installation in Western Australia under VSB 6 P1. The vehicle-specific installation was inspected and tested. The certification covers the coupling modification; it does not establish an increased GVM, GCM or towing capacity.

Western Australia

RAM 2500 Rear Axle & 5,800 kg GVM Upgrade — WA

GVM, Heavy vehicle, Vehicle Modification

Engineering certification of a RAM 2500 GVM increase from 5,460 kg to 5,800 kg and rear axle rating increase from 2,740 kg to 3,078 kg. The WA-certified package included replacement suspension, airbag assistance and a long-range fuel tank under VSB 6 A2, F1, G4, M1, P1, S1 and S2.

Western Australia

RAM 2500 GVM Upgrade to 5,460 kg — WA

GVM, Heavy vehicle, Vehicle Modification

Engineering certification of a RAM 2500 GVM increase from 4,495 kg to 5,460 kg and category change from NB1 to NB2 in Western Australia. Assessed under VSB 6 G4, P1, S1 and S2 within the original axle ratings, with no suspension modification required.

New South Wales

RAM 2500 GVM Upgrade to 6,000 kg — NSW

GVM, Heavy vehicle, Vehicle Modification

Engineering certification of a 2025 RAM 2500 GVM increase from 4,495 kg to 6,000 kg, including a revised 3,300 kg rear axle/suspension rating. Assessed under VSB 6 codes D3, E3, F1, G4, P1, S1 and S2; GCM remained 12,750 kg.

Queensland

Isuzu NPS 300 GVM & GCM Upgrade — Queensland

GVM, GCM, Heavy vehicle

Queensland-certified Isuzu NPS 300 heavy-vehicle upgrade: GVM increased from 6,000 kg to 7,500 kg and GCM from 9,500 kg to 11,000 kg following vehicle-specific engineering assessment and brake testing under VSB 6 codes G4, S1, S2 and S3.

South Australia

RAM 2500 GVM Upgrade to 4,622 kg

GVM, Heavy vehicle

Engineering certification of a factory RAM 2500 category change from NB1 to NB2, with a revised GVM of 4,622 kg under VSB 6 S1.

New South Wales

Isuzu NPS 75-155 GVM & GCM Upgrade — NSW

GVM, GCM, Heavy vehicle

Engineering certification of an Isuzu NPS 75-155 GVM increase from 7,500 kg to 7,995 kg and GCM increase from 11,000 kg to 12,000 kg under VSB 6 G4, S1, S2 and S3.

Western Australia

Chevrolet Silverado 2500 GVM Upgrade to 5,500 kg

GVM, Heavy vehicle, Vehicle Modification

Engineering certification of a Chevrolet Silverado 2500 GVM increase from 5,148 kg to 5,500 kg, including front and rear suspension, axle and fuel-tank modifications.

Western Australia

Isuzu NPS 75-155 GVM & GCM Upgrade

GVM, GCM, Heavy vehicle

Engineering assessment and certification of an Isuzu NPS 75-155 GVM increase from 7,500 kg to 8,000 kg and GCM increase from 11,000 kg to 12,000 kg, with a super-single wheel conversion under VSB 6 G4, S1, S2 and S3.

Queensland

Mazda BT-50 GVM Upgrade

GVM, Heavy vehicle

GVM re-rating for a 2017 Mazda BT-50 via upgraded suspension under the QLD LS15/LS11 code, with revised tyre placard and load capacity labelling.

Western Australia

Mitsubishi Rosa Bus Seating Reconfiguration

Heavy vehicle, Vehicle Modification

Seating capacity certification for a Mitsubishi Rosa bus, additional/replacement seats installed on existing factory anchorage points, certified to VSB 6 K1.

Western Australia

Isuzu Super Single Wheel Conversion

Heavy vehicle, Vehicle Modification

Conversion of an Isuzu coach from dual rear wheels to super single tyres for Pinnacle Coaches.

Northern Territory

Denning Bus-to-Motorhome Conversion

Heavy vehicle, Vehicle Modification

Conversion of a 1989 Denning "Mobile Home" omnibus into a motorhome — new motorhome-style windows and an aftermarket captain's chair installed at the driver's position. Certified under Vehicle Standards Guide 5 and VSB 6 (cabin conversion, seat/seatbelt anchorage).

Western Australia

Truck Bull Bar

Heavy vehicle, Vehicle Modification

ADR 84/00 compliance certification for the KP BB 4 front underrun protection bull bar fitted to UD CWB trucks. Finite Element Analysis (linear, non-linear and explicit dynamic) confirmed the device meets required deflection and ground clearance limits, with a minimum safety factor of 2.5.

Western Australia

Isuzu NPS 75 Tow Pin Rating

GVM, Heavy vehicle, Vehicle Modification

Assessment of an Isuzu NPS 75 tow pin under a defined 4.5-tonne static load case. The model returned a safety factor of 3.7 against yield for the nominated component and assumptions—not a separate towing or recovery rating.

Northern Territory

Toyota Landcruiser 79 series GVM upgrade to 4.5t

GVM, Heavy vehicle

GVM upgrade for a Toyota Landcruiser 79 Series, taking GVM from 3,510kg to 4,500kg. Engineered with ARB Old Man Emu suspension and an extended rear axle, backed by Finite Element Analysis of the differential and axle to confirm structural strength at the increased rating. Approved by NT Transport under VSB 6.

Victoria

Silverado 2500 GVM upgrade to 6t

GVM, Heavy vehicle, Vehicle Modification

Upgraded suspension, brake system certification, GVM upgrade to 6t, axle re-rating for this Silverado 2500.

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 6.2t 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.

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Independent engineering you can trust

Engineering - led

Independent engineering assessment
Vehicle intended purpose driven
Vehicle-specific advice

GVM & related systems

GVM upgrade assessment
Axle, suspension and braking considerations
GCM and towing assessed separately where required

Australia wide

Darwin-based engineering team
Remote project support
Inspection partner network across Australia

Experienced engineering

15+ years of engineering experience
Complex and bespoke vehicle modifications
Practical technical advice

Frequently asked questions

Can KME Vehicle Engineering assess a heavy vehicle GVM or GCM upgrade?

Yes. KME assesses the vehicle, proposed mass increase, axle ratings, suspension, braking, wheels and tyres, intended use and jurisdiction to determine the appropriate engineering pathway.

Can KME Vehicle Engineering help with heavy vehicles outside Darwin?

Yes. KME Vehicle Engineering is based in Darwin and supports heavy vehicle projects across Australia using remote engineering review and an inspection partner network where appropriate.

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.

Does a suspension or wheel change automatically increase GVM or GCM?

No. Suspension, wheel or tyre changes do not automatically increase a vehicle’s GVM or GCM. Any mass-rating change requires separate engineering assessment and an applicable certification pathway.

What heavy vehicle modifications can KME Vehicle Engineering assess?

KME Vehicle Engineering provides engineering assessment and certification for modifications including GVM and GCM upgrades, VSB 6 modifications, chassis and body changes, suspension and wheel modifications, seating, towing systems and other complex heavy vehicle work.

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.

What is VSB 6?

VSB 6 is a technical framework used for many heavy vehicle modifications in Australia. The applicable approval and certification process still depends on the vehicle, modification and registration jurisdiction.

Who can certify a heavy vehicle modification under VSB 6?

The person authorised to certify a heavy vehicle modification depends on the modification and the vehicle’s registration jurisdiction. In jurisdictions operating under the NHVR heavy vehicle modification scheme, applicable VSB 6 modifications are generally certified by an appropriately accredited Approved Vehicle Examiner (AVE). Other jurisdictions, including the Northern Territory, have their own approval and signatory arrangements.KME Vehicle Engineering provides heavy vehicle engineering assessment and certification services and can identify the applicable engineering, inspection and certification pathway for your vehicle and jurisdiction.

What heavy vehicle modifications may require VSB 6 certification?

VSB 6 covers many common modifications to heavy motor vehicles and heavy trailers, including changes involving engines, driveline components, axles, steering, wheels and tyres, suspension, brakes, chassis, bodies, seating, fuel systems, tow couplings, vehicle-mounted lifting systems and vehicle ratings such as GVM and GCM.The applicable VSB 6 modification codes, engineering evidence and certification requirements depend on the vehicle, the proposed modification and the registration jurisdiction.

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