Gross Vehicle Mass (GVM) Explained!
What is GVM?
Gross Vehicle Mass (GVM) is the term used to describe the total weight a vehicle can safely operate at. Gross vehicle mass includes the combined weight of the vehicle (tare weight) and it’s load.
For example, a Pinto Trailers' 7x4 1200kg GVM Trade Wellside trailer has a tare weight of 200kg, therefore the maximum payload the trailer can carry is 1000kg or 1 tonne (1200kg-200kg).
I don’t know my trailer’s GVM?
There are several ways to check your trailer’s GVM,
- check the New Zealand motor vehicle register
- ask your mechanic at your next Warrant of Fitness or service
- call the manufacturer, depending how old your trailer is, they may have records on your model
Make sure you also check your trailer's tare weight at the same time, the manufacturer may have this information or you can find local weigh stations online, try your local truck stop or mechanic or tyre service centre. Rubbish tips and scrap metal businesses may also be able to weigh your trailer for you as well.
Crunching the numbers
When considering the maximum load of your trailer, also think about if you have added any aftermarket accessories, for example a rubbish cage can add 60kg and increasing the height of the sides can add up to 20kg of extra weight. Knowing exactly what tare weight your trailer and basic accessories are is important for how much load you can actually carry safely.
Weights of common items hauled by trailers:
|
Item |
Approximate weight kg |
|
1 cubic metre of soil |
1300kg |
|
1 cubic metre of sand |
1620kg |
|
10 sheets of standard 10x 1200x2400 wallboard |
187.2kg |
|
1000L filled water IBC tank |
1065kg |
|
Family tent, small bbq, gas bottle, 90L chilly bin filled, camping furniture, 2 kayaks, 4 wetsuits, 2 H frames, 4 bikes. |
255kg |
|
Quad Bike, extra fuel, fishing tackle, chilly bin, ice, box of beers. |
355kg |
Final thoughts on safety and GVM
Overloading is the biggest cause of damage to trailers, it can stress the welds, bend the the axles, add pressure to your drawbar which may cause bending, increase pressure on tires causing blowouts and most worryingly the more weight you carry you greatly increase your stopping distance when braking suddenly, the extra weight causes extra momentum which can be horrific in the wrong circumstance.
Whilst carrying an overweight load can cause major damage to your trailer and increase your risk of crashing, it is also an offence. Your trailer's GVM is recorded on the Motor Vehicle Register and can be tested by police at any police weigh check points and can incur fines.