Legal 4WD modifications: NSW and Victoria

The lift kit is in the shed, still in the box, and the real question is whether fitting it turns a legal vehicle into a defectable one. On this side of the country the answer depends on which bank of the Murray the vehicle is registered on, and the gap is wider than most people fitting kits realise. Victoria lets an off-road 4WD run a combined suspension and tyre lift of 75mm with no certificate at all. New South Wales stops at 50mm. Same vehicle, same kit, ten minutes apart.

What follows is drawn from the regulators' own published documents, current as at August 2026: Vehicle Standards Bulletin 14, Transport for NSW Vehicle Standards Information No. 6 (Revision 4, issued 1 July 2026), and the Transport Victoria guidelines VSI 8 and VSI 1. It is not legal advice, and no certifier or signatory is bound by it. Where a figure matters to a build, read the source document and ring the regulator before spending money.

One national code, two sets of paperwork

Vehicle Standards Bulletin 14 is the National Code of Practice for Light Vehicle Construction and Modification, published by the Commonwealth Department of Infrastructure and prepared by the Australian Motor Vehicle Certification Board Working Party. It is currently at Version 2, assembled section by section. The part that governs lifts and tyres is Section LS, Tyres, Rims, Suspension and Steering, Version 2.1, dated 1 November 2015.

The bulletin is blunt about its own limits.

VSB 14 essentially provides the technical requirements that need to be met when modifying or constructing a vehicle. It does not cover the administrative requirements of each State and Territory.

Registration processes, fees, inspections, approval applications and the administration of signatory schemes all sit with the states. Where a jurisdiction cannot recognise part of the code, the difference is noted inside the code itself, and the reader is told to contact their registration authority. That single arrangement is why this guide exists. VSB14 is the same document in Albury and Wodonga. Everything wrapped around it is different.

In New South Wales the scheme is the Vehicle Safety Compliance Certification Scheme. Individuals hold the licence, not businesses, and the minimum qualification is a Certificate IV in engineering or an automotive discipline, backed by $20 million public liability and $5 million professional indemnity insurance. Licensed certifiers issue VSCCS Compliance Certificates. Older Engineering Certification Scheme certificates are no longer accepted by Transport for NSW for registration purposes. Which modifications count as significant is declared in the Declaration of Modification Order 2026, gazetted, and explained item by item in VSI 06.

In Victoria the scheme is the Vehicle Assessment Signatory Scheme. A VASS signatory issues a VASS approval certificate and fixes a blue modification plate to the vehicle carrying the certificate number and the modification code. Regulation 293 of the Road Safety (Vehicles) Regulations 2021 makes it an offence to use a modified vehicle on a highway unless the modification is approved by VicRoads or carried out in accordance with guidelines published by VicRoads. VSI 8, published October 2021, is that guideline.

The 50mm rule, and the Victorian exception

Section LS allows a set of basic modifications without certification, provided the total change in vehicle height from everything done to the vehicle does not exceed 50mm. Clause 4.11 sets out how that 50mm may be reached: body blocks or a lift kit (50mm maximum if nothing else changes height), a suspension modification (50mm maximum on the same basis), a change in tyre diameter (maximum 50mm change in diameter), or a combination of those totalling not more than 50mm.

The trap sits in that last option. A 50mm increase in tyre diameter lifts the vehicle 25mm, because only the radius sits under the axle. Fit a 50mm spring lift and 50mm larger tyres and the total height change is 75mm, which is over the national line. That is precisely the combination a lot of touring builds run.

Between 50mm and 150mm the work moves into Codes LS7 (the design) and LS8 (the physical modification), and the vehicle must pass an ISO 3888-1 double lane-change test, the procedure for which sits in Section LT, Code LT4. Beyond 150mm the code does not cover the modification at all. Nor does it cover raising any vehicle whose wheel track has been reduced, which the code sends back for case-by-case assessment.

Section LS also carries conditions people routinely forget. Front and rear must be raised by the same amount so the original attitude is retained. At least two thirds of the original rebound travel must be kept. Extended or adjustable shackle plates must not be used to raise a leaf-sprung vehicle.

Victoria then departs from all of it for one class of vehicle. VSI 8 sets out an alternative to Section LS for off-road type 4WDs of ADR category NA, NB1, MC or MD, and in the guideline's own words, only in this case: a combination of suspension lift and larger diameter tyres giving a total lift of up to 75mm, without the testing and certification VSB14 would otherwise require above 50mm. The suspension may go up 50mm and the tyre radius up 25mm.

The conditions attached are not decoration. The kit must be commercially available and manufactured and supplied by a corporation. It must be specifically designed and tested by the kit manufacturer for the make, model and variant being modified, to establish no adverse effect on rollover propensity, handling, braking performance and structural integrity when assessed at the combined 50mm lift and 25mm tyre radius increase. It must be fitted to the kit manufacturer's instructions. And the manufacturer must supply a written statement of suitability, which the owner keeps. No statement, no concession.

Victoria separately allows tyres up to 50mm larger in diameter on an off-road 4WD, provided that with the wheels straight ahead they do not project beyond the extreme width of the mudguards when viewed from above, and do not foul bodywork, braking, suspension or steering under any combination of suspension and steering movement.

New South Wales has no equivalent concession. VSI 06 item 13 requires certification for any change in ride height from a suspension modification of more than 50mm, or a change of more than one third of the working suspension travel, whichever bites first. Lowering by more than 50mm needs a certificate too.

Where the rules differ

Tyres: a millimetre rule and a percentage rule

VSB14 clause 4.2.4 works in millimetres. On a passenger car or passenger car derivative, overall tyre diameter must not be more than 15mm larger or 26mm smaller than any tyre designated by the manufacturer for that model. On 4WD passenger vehicles specifically designed for off-road use (typically MC), 4WD goods vehicles and their 2WD equivalents (N category), and medium weight goods vehicles (NA2, NB), the figure is 50mm larger and 26mm smaller. All-wheel-drive soft roaders are expressly not in the off-road category, even where they carry an MC classification.

New South Wales does not use that millimetre figure to decide certification. VSI 06 item 15 uses a percentage. Certification is required where overall tyre diameter changes by more than 7% of the largest diameter specified by the manufacturer on the Road Vehicle Descriptor or the tyre placard, or where speedometer compliance is affected. The worked example Transport for NSW publishes: 215/65R17 at 712mm overall going to 265/65R17 at 776mm is an increase of 64mm, or 8%, and needs certification. The same vehicle on 235/65R17 at 738mm is an increase of 26mm, or 4%, and does not, provided the speedometer still complies.

Seven per cent of a 712mm tyre is about 50mm, so on a mid-size wagon the two rules land close together. On a smaller starting diameter the NSW percentage is tighter than 50mm. On a larger one it is looser. Do the arithmetic against the actual placard rather than assuming the national figure carries.

Two further NSW thresholds are worth knowing. Item 16 requires certification where rim or tyre width exceeds the largest combination the manufacturer specifies by more than 25.4mm, one inch. Item 17 catches any wheel and tyre combination that falls below the manufacturer's minimum load carrying specification, with car tyres fitted to a vehicle specified for light truck tyres given as the example.

VSB14 also caps the wheel track increase for MC, NA and NB vehicles at 50mm beyond the manufacturer's maximum, which is what constrains offset and spacer choices, and requires front and rear aspect ratios to sit within 10 of each other. Victoria adds a marking rule: alloy wheels must be legibly and durably marked to show compliance with AS 1638, DOT, JWL, JWL-T, JIS, KBA or VIA, and repaired or damaged alloy wheels are not acceptable.

Stability control changes the answer

Section LS clause 2.6 draws a line around electronic stability control. A vehicle fitted with ESC and lifted up to 50mm on suspension alone stays within the basic modification path. Above 50mm, or where the lift comes from a combination of suspension, tyres or body blocks, Code LS7 or LS8 applies.

Victoria requires evidence from the vehicle manufacturer, the kit manufacturer or testing to determine the impact on the ESC system, and anything outside that needs a VASS approval certificate with the signatory confirming ongoing ESC operation. The control unit must not be disconnected. Anyone weighing up a build should raise this with a 4WD specialist before ordering parts, because on a late model vehicle it decides whether the job is a bolt-on or a certification exercise.

What certification involves, and what it costs

In New South Wales the certifier inspects, assesses, analyses and tests, then issues a VSCCS Compliance Certificate if the vehicle complies. Certificates do not expire, and each modification needs certifying only once. The certificate then goes to a service centre with the vehicle's records.

In Victoria the sequence is: talk to a signatory before starting, do the work, present the completed vehicle for final approval and certification, then present vehicle and certificate to VicRoads. A light vehicle VASS approval certificate is valid for 30 days from the date of issue, so the VicRoads appointment cannot drift.

Cost is where both regulators step back. VicRoads states plainly that it does not regulate or specify the cost of services performed by a VASS signatory. Transport for NSW says fees for inspecting and certifying vehicles are negotiated between certifiers and their customers. What follows is an indicative range only, drawn from what certifiers and 4WD workshops in the Albury Wodonga, Wagga and Goulburn Valley corridor commonly quote for this class of work. It is not a price list and nobody is bound by it.

• A straightforward lift certification on a common model with an off-the-shelf kit: roughly $450 to $900.
• Where design approval, a lane-change test or non-standard components are involved: $1,000 to $3,000 and upwards.
• GVM upgrades, seat work and chassis work: quoted separately, and usually higher again.

Government charges sit on top and those are published. In Victoria a vehicle inspection for registration at a VicRoads Customer Service Centre is a $22.10 appointment fee plus a $35.20 inspection fee, $57.30 in total. Those figures are current as at August 2026 and are reviewed periodically.

Certifiers are thin on the ground away from the capitals, and the ones who take 4WD work are usually booked out. Ring before the kit is ordered, not after it is fitted. Both regulators recommend exactly that.

Bull bars, airbags and two technical specifications

Victoria treats fitting a bull bar as a modification, approved under VSI 1 if it meets the design requirements of sections 1, 2 and 3.1 of AS 4876.1-2002. The front axle rating must not be exceeded when the vehicle is loaded to GVM. The bar must be mounted using the attachment points provided by the vehicle manufacturer, and must be designed and mounted to avoid misaligning loads that may prevent the vehicle structure and airbag system from functioning effectively in a crash, with attachment points set apart from any airbag sensors on the front structure. Forward offset must not exceed 75mm or 9 degrees.

New South Wales went a different way. Until September 2014 the Regulation required frontal protection systems on certain vehicles to comply with AS 4876.1. It no longer does. Transport for NSW instead publishes its own Technical Specification, Requirements for vehicle frontal protection systems fitted to light vehicles, September 2019. Bull bars are not listed as a significant modification requiring a compliance certificate, but the vehicle must still comply with Schedule 2 of the Road Transport (Vehicle Registration) Regulation 2017 and the applicable Australian Design Rules, including ADR 69/00 and ADR 73/00 on frontal impact occupant protection.

Under that specification the bar must be compatible with the vehicle, and the bar manufacturer must state so and supply the information needed to fit it correctly. Every bull bar must be permanently marked in English with the manufacturer, supplier or importer details, the make, model, type and years of the vehicles it is intended for, a statement that it must not be fitted to any other vehicle, and advice that the bar and its fixings must not be modified and that nothing may project forward of its forward profile. It must not increase overall width beyond the standard mirrors, or where there are no mirrors, by more than 150mm each side, and total width must stay under 2.5m. Minimum running clearance is 100mm, measured unladen.

One line in that document deserves quoting to anyone putting a heavy bar on a ute. Transport for NSW research found that a heavy duty bull bar fitted to a sedan-type vehicle can make the damage worse in an 80 km/h collision with a kangaroo, and the specification recommends against the combination, naming Commodore and Falcon utes.

Air suspension is another split. Replacing coil or leaf springs with airbags in Victoria needs a VASS approval certificate, plus a list of conditions: ride height of an individual wheel or axle cannot be altered while the vehicle is in motion, two thirds of original suspension travel must be retained at all selectable ride heights while moving, original attitude maintained, a minimum running clearance of 100mm at all selectable heights moving and parked, servicing and diagnostic mode disabled on public roads, a non-return valve so the bags stay inflated if the compressor fails, a drain valve on the tank, and an audible or visual warning to the driver of any height or pressure change or compressor failure. Airlines must be made to a standard such as SAE J844 and reservoirs to SAE J10. New South Wales handles it through VSI 06 item 14: leaf-to-coil and variable air conversions need certification, but rear supplementary air springs on unmodified mounting points, or air springs that change ride height by up to 50mm, do not.

At a defect stop

Victoria issues four categories: a major defect notice, a minor defect notice, a self-clearing notice for heavy vehicles, and a formal warning. They can come from Victoria Police, the National Heavy Vehicle Regulator, Department of Transport and Planning Vehicle Safety Partners and Standards, Safe Transport Victoria, and equivalent interstate inspectors. The notice carries a prohibit time, and past it the vehicle cannot be driven and must be towed or trailered. It must be cleared within 28 days of the issue date or registration is suspended. Clearing it at a VicRoads Customer Service Centre costs $57.30 with an inspection or $22.10 without, current as at August 2026.

In New South Wales, modifying a registered light vehicle by adding, removing or altering components so that it no longer complies with the applicable vehicle standards is an offence under the Road Transport (Vehicle Registration) Regulation 2017, unless the modification is exempted by Transport for NSW. Enforcement runs through police and authorised officers, and the practical outcome is the same: the vehicle comes off the road until it is repaired or certified.

Paperwork is what shortens the roadside conversation. In Victoria that means the kit manufacturer's written statement of suitability, kept with the vehicle. In New South Wales it means the VSCCS Compliance Certificate.

Does a certificate cross the river?

The code crosses. The certificate does not.

The VSB14 introduction goes as far as saying the code is nationally recognised, and no further. Certification schemes are administered by each jurisdiction, and signatories are accredited to the jurisdiction they work in. Neither Transport for NSW nor VicRoads publishes a rule recognising the other state's modification certificates.

Take the case that comes up constantly along this border: a lifted Hilux bought in Wodonga and registered in Albury. New South Wales requires an inspection at an Authorised Unregistered Vehicle Inspection Station, and where the vehicle is modified or non-standard, a Compliance Certificate from a NSW licensed certifier as well. The Victorian paperwork is evidence to hand that certifier. It is not a substitute for the NSW certificate. And if the vehicle is sitting on a Victorian 75mm lift, the NSW certifier is assessing it against the NSW threshold, which is 50mm. Budget for the certificate, or for taking the lift back down.

In the other direction, VicRoads advises at booking whether a vehicle coming from interstate needs an inspection, and the modification may need a VASS approval certificate before the vehicle is registered. Remember the 30-day validity when arranging the two appointments.

Driving across for the day is a separate question, and one neither regulator answers cleanly in published material. A vehicle registered in Victoria is built to Victorian registration standards, but a NSW officer who forms the view that a vehicle is unsafe is not obliged to ignore it, and Victoria's own defect notice page contemplates equivalent interstate inspectors issuing notices. For anything close to the line, Transport for NSW Technical Enquiries takes questions on 1300 137 302.

Before the kit is ordered

1. Find the tyre placard and the Road Vehicle Descriptor figures. Both states key their rules off those numbers, not off the tyre on the shelf.
2. Work out the total height change, not the spring figure. Tyre diameter increase divided by two, plus the springs, plus any body blocks.
3. Decide which state the vehicle will be registered in for the next five years, not which one it sits in today. A Victorian build that will be sold into the Riverina is a NSW build.
4. Ring a certifier or a signatory before buying. Both regulators say to do it, and the phone call is free.
5. Keep the kit manufacturer's written statement of suitability. In Victoria it is the concession itself. Everywhere else it is the evidence.

Local starting points: 4WD accessory suppliers in Albury, 4WD accessories in Wodonga, 4WD specialists in Wangaratta, mechanics in Wagga Wagga and mechanics in Shepparton. The full category lists sit at 4WD accessories and mechanics.

Sources

Checked on 2026-08-25. Government fees and rules are indexed and revised, so open the source before you rely on a figure.

• infrastructure.gov.au
• nsw.gov.au
• roadsafety.transport.nsw.gov.au
• transport.nsw.gov.au
• transport.vic.gov.au
• vicroads.vic.gov.au