Modifying a tow vehicle — through a GVM upgrade, a GCM upgrade, or heavier-duty suspension — can take it outside the specifications it was built and registered to. Without an engineer's certification, those modifications may not meet Australian Design Rules (ADRs), which can affect both roadworthiness and insurance outcomes. This guide explains what tow vehicle certification covers, when GVM, GCM, and ATM limits require an engineer's sign-off, and how the VSB14 and VSB6 codes

A factual guide to VSB 6, including which vehicles it covers, common and specific modifications, Section S rating changes and jurisdictional approval requirements.

When you move from factory duals to a Super Single conversion, you’re not just changing the look of your vehicle — you’re changing its performance envelope. Those big single tyres carry more weight per wheel, handle heat differently, and respond more sharply to under- or over-inflation. At highway speeds, that makes tyre pressure one of the most important — and most misunderstood — factors in keeping your rig safe, efficient, and predictable.