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Tow More - up to 4,500Kg with GCM Increase*

Is your rig over loaded? The Truth about GVM’s and GCM’s and Six Wheelers.


Modern dual cab 4WD utes boast some impressive towing and load carrying figures, with many stating 1 tonne payloads and 3½ tonne towing (Ranger, Hilux, BT50, Dmax, Navara, Amarok). But if you have a ton on the back of a dual cab fitted with a bull bar, side steps, roof rack etc, then there is a good chance that you have exceeded your rear axle capacity and exceeded your legal GVM of the vehicle, and that could be without including passenger or a trailer's towball weight.


Some of the worst examples are actually the biggest on the road, with the 200 series Landcruiser and Ram 1500's offering lower payloads from factory than the smaller dual cab utes.


A Six Wheeler Conversion will upgrade the vehicle's GVM and offers vastly improved weight distribution, allowing you to carry more, & we have the potential to upgrade the towing capacity on a range of our federally approved conversions. A GCM value can be applied to vehicles in the Heavy Vehicle category.


Let us explain the terminology:

GVM = Gross Vehicle Mass:

Gross Vehicle Mass is the maximum permitted total weight of your vehicle and its entire load, including all passengers & accessories, including fuel & the tow ball download weight.  This is stated by the manufacturer & can be found on the OEM compliance plate. It is illegal to exceed your vehicles GVM.


Tare weight is the unladen weight of the vehicle. It includes any permanently attached accessories, such as a bullbar. It does not include any removable items, such as luggage or tools.


Payload = GVM minus Tare and is the available weight you can carry

eg a Ford Ranger has a GVM of 3,200Kg. With a full tank of fuel, tray, canopy and bull bar, it might tare at approx 2,500Kg, giving a payload of 700Kg (3,200Kg minus 2,500Kg).

That 700Kg then has to include passengers & tow ball weight and other items carried, so it is very easy to exceed a GVM by adding too much payload.

GCM = Gross Combination Mass:

Gross Combination Mass is the maximum weight of the vehicle & trailer together and generally only applies to Heavy Vehicles..

For most of our completed Six Wheeler Conversions, we are able to achieve a GVM of 4,495Kg, and a towing capacity either maintained at 3,500Kg or increased up to 4,500Kg.

Our Heavy Vehicle variants have a specified GCM of between 8210kg and 9300kg.

ATM = Aggregate Trailer Mass

The ATM is the maximum legal loaded weight of your trailer or caravan standing alone on a jockey wheel.




And so, from a weight distribution perspective, a Six Wheeler is the only sensible way to tow trailers above 3,000Kg & or a gooseneck/5th wheeler.  It is also the safest way to control these trailers with heavy loads. Because of the way we build our EYE- -TIE ute trays, and the way we mount them to the chassis,  a gooseneck or 5th wheeler hitch can easily be added into the new tray as we build it for maximum strength and durability.

*Please note that all weights quoted above were correct at time of publication, but may vary due to changes in state government legislation, and the regulations can vary from state to state for a previously registered vehicle.

GCM And How It Applies To You

GVM & GCM Legal Compliance