NB1 vs NB2: What Changes When You Upgrade Your GVM

Everybody talks about the GVM upgrade. Nobody talks about what happens after.

If you're running a big American truck in Australia and you're looking at a Gross Vehicle Mass (GVM) upgrade, there's a good chance you're going to cross a line that most people don't know exists. That line sits at 4,500kg. Cross it, and your vehicle moves from NB1 category into NB2 — and that changes a few things for you as the driver.

At 5300kg this RAM 2500 sits in the NB2 vehicle category — a different licence class, different road rules, and a truck that's built to actually use that rating.

What Are NB1 and NB2?

Australian Design Rules (ADR) are the rulebook manufacturers have to follow before a vehicle can be sold here. Part of that framework is a category system for trucks and heavier vehicles.

NB1 covers vehicles with a GVM up to 4,500kg. NB2 sits above that. The RAM 2500, as an example, comes into Australia as NB1 — it has a factory GVM of 4,495kg. Right on the edge. Do a GVM upgrade that takes it past that threshold, and it becomes an NB2 vehicle. Simple as that.

What Changes for You When You Upgrade to NB2?

Your Licence

Once your vehicle is registered as NB2, your standard car licence no longer covers you to drive it. You'll need a Light Rigid (LR) licence. The process is similar to getting your licence for the first time — a theoretical test and a practical assessment. The difference is you're doing it in a big rig instead of a Hyundai Getz.

Your Blood Alcohol Level

As a heavy vehicle driver, you're subject to zero BAC - meaning no alcohol whatsoever in your system when you're behind the wheel. Not 0.05 like a regular car licence. It doesn't matter that your daily driver happens to be a RAM 2500 - the law sees a heavy vehicle, and it holds you to a heavy vehicle standard. If you're planning a weekend away with the truck, factor that in before cracking a beer the night before you drive home.

Your Tolls

Heavy vehicles pay more at the toll gate. Your registration category changes when the vehicle moves to NB2, which means every toll road you drive through is going to cost more than it did before. Not a dealbreaker, but it adds up if you're using toll roads regularly.

Your Speed Limits

Some states don't allow heavy vehicles to exceed 100km/h, even on roads posted at 110km/h. If you're driving interstate, you need to know the rules for each state before you get behind the wheel. Ignorance isn't a defence when you're driving a classified heavy vehicle.

The suspension is what makes the NB2 rating real — FOX remote reservoir shocks engineered to handle the load

Is NB2 the Right Move?

That depends on what you need your truck to do. If you need serious payload capacity — for a canopy build, heavy gear, or towing — and the licence and operating requirements work for your situation, NB2 is the path that makes it all legal and usable.

We're currently doing NB2 upgrades on RAM 2500s and Silverado 2500HDs here in Brisbane. If you want to know what's available for your vehicle, check out our GVM upgrades page or get in touch below.

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