Vehicle Standards Bulletin 6 (VSB6) V3.2: National Code of Practice Heavy Vehicle Modifications is the national standard for the most common modifications made to heavy vehicles. Under the NHVR Code of Practice for the Approval of Heavy Vehicle Modifications (PDF, 506KB) the NHVR has set VSB6 as the primary standard used by Approved Vehicle Examiners (AVEs) to approve modifications to heavy vehicles.
VSB6 V3.2 Introduction (PDF, 783KB)
Section A - Engines (PDF, 2.9MB)
A1 Checklist - Engine substitution (DOCX, 50KB)
A1 Modification report - Engine installation (DOCX, 42KB)
A2 Checklist - Air cleaner substitution or additional fitting (DOCX, 43KB)
A3 Checklist - Turbo charger installation (DOCX, 44KB)
A4 Checklist - Exhaust system alteration (DOCX, 42KB)
A5 Checklist - Road speed limiter installation (DOCX, 51KB)
Section B - Transmissions (PDF, 934KB)
Section C - Tail Shafts (PDF, 1.4MB)
C1 Checklist - Tail shaft modification (DOCX, 43KB)
C1 Modification report - Tail shaft modification (DOCX, 44KB)
Section D - Rear Axles (PDF, 624KB)
D1 Checklist - Rear axle installation (DOCX, 47KB)
D2 Checklist - Differential substitution (DOCX, 42KB)
D3 Checklist - Fitting of non-standard rear wheel components (DOCX, 55KB)
<Section E - Front Axle Steering Wheels & Tyres (PDF, 3.3MB)
E1 Checklist - Front axle installation (DOCX, 48KB)
E2 Checklist - Steering alteration (DOCX, 51KB)
E2 Modification report - Front axle and steering (DOCX, 54KB)
E3 Checklist - Fitting of non-standard front wheel, i.e. tyre or rim (DOCX, 48KB)
Section F - Suspension (PDF, 1.4MB)
F1 Checklist - Suspension substitution (DOCX, 45KB)
F2 Checklist - Trailer suspension modifications (DOCX, 45KB)
Section G - Brakes PDF, (7.1MB)
G Modification report - Air system re-charge data sheet (DOCX, 43KB)
G1 Checklist - Relocation of air brake components (DOCX, 45KB)
G2 Checklist - Installation of trailer braking controls: air brakes (DOCX, 46KB)
G3 Checklist - Trailer brake system upgrade (DOCX, 52KB)
G4 Checklist - Brake system certification (DOCX, 53KB)
G4 Modification report - Brake system (pre-ADR vehicle) (DOCX, 34KB)
G4 Modification report - Brake system: ADR certified vehicle (DOCX, 46KB)
G4 Test report - Brake torque build-up check: adjacent axles (DOCX, 63KB)
G5 Checklist - Fitting of auxiliary and endurance brakes (DOCX, 46KB)
G6 Checklist - Fitting of air operated accessories (DOCX, 48KB)
G7 Checklist - Brake system substitution/wheelbase extension (DOCX, 46KB)
G8 Checklist - Trailer brake system upgrade (design) (DOCX, 50KB)
Section H - Chassis (PDF, 7.8MB)
H Calculation sheet - Chassis modification (DOCX, 44KB)
H1 Checklist - Wheelbase extension outside OEM options (DOCX, 50KB)
H2 Checklist - Wheelbase reduction outside OEM options (DOCX, 50KB)
H3 Checklist - Wheelbase alterations within OEM options (DOCX, 47KB)
H4 Checklist - Chassis alteration (DOCX, 50KB)
H5 Checklist - Trailer chassis modifications (DOCX, 49KB)
Section J - Body Mounting (PDF, 2.7MB)
J1 Checklist - Body mounting (DOCX, 51KB)
J2 Checklist - Fitting of truck-bus body (DOCX, 44KB)
J3 Checklist - Fitting of roll-over or falling object protection system (DOCX, 45KB)
J4 Checklist - Tipper bodies (design) (DOCX, 44KB)
Section K - Cabin (PDF, 3.5MB)
K1 Checklist - Seating capacity alteration, seat, seatbelt and anchorage installation (DOCX, 47KB)
K2 Checklist - Certification of seat and of seat belt anchorage (DOCX, 45KB)
K3 Checklist - Cabin Conversion (DOCX, 46KB)
K5 Checklist - Installation of wheelchair occupant restraint system (DOCX, 43KB)
K6 Checklist - Child restraint anchorage installation (DOCX, 50KB)
Section M - Fuel Systems (PDF, 588KB)
Section P - Tow couplings (PDF, 2.9MB)
P1 Checklist - Towbar and coupling installation other than fifth wheels and kingpins (DOCX, 46KB)
P2 Checklist - Fifth wheel and kingpin installations (DOCX, 52KB)
P2 Evaluation sheet - Fifth wheel and turntable evaluation report (DOCX, 68KB)
Section R - Vehicle Mounted Lifting Systems (PDF, 2.3MB)
R1 Checklist - Installation of vehicle mounted lifting systems (DOCX, 49KB)
R1 Assessment report - Vehicle mounted lifting systems (DOCX, 72KB)
R2 Checklist - Wheelchair loader installation (DOCX, 44KB)
Section S - Vehicle Rating (PDF, 7.2MB)
S1 Checklist - GVM/GCM re-rating (DOCX, 51KB)
S2 Checklist - GVM re-rating (design) (DOCX, 51KB)
S3 Checklist - GCM re-rating (design) (DOCX, 51KB)
S7 Checklist - ATM/GTM re-rating (DOCX, 53KB)
S8 Checklist - Motor vehicle road train rating (DOCX, 53KB)
S9 Checklist - Prime mover B-double rating (DOCX, 54KB)
S11 Checklist - Road train trailer rating (DOCX, 54KB)
S12 Checklist - ATM/GTM re-rating (design) (DOCX, 52KB)
Section T - Tow Trucks (PDF, 2.2MB)
T1 Checklist - Construction of tow trucks (DOCX, 52KB)
T2 Checklist - Design of tow trucks (DOCX, 42KB)