When looking at vehicle weights there are acronyms every where but what does it all mean? Here we will give a run down on what they refer to and how various weights may affect your vehicles safety and road regulation compliance. Some of these weight limitations can be safely increased on suitably modified cars and caravans.
Tare – Tare weight
The Tare weight is the unladen ( or empty) weight of the vehicle at time of manufacture. In the case of a car or caravan this is before any extras or “factory options” are fitted.
GVM – Gross Vehicle Mass
Gross Vehicle Mass is the maximum weight of a vehicle determined by the manufacturer, this is the tare weight plus load carrying capacity.
A GVM upgrade is a common modification to increase load carrying capacity or payload and improve safety and road holding on loaded vehicles. It involves improved suspension and certification of modifications.
GCM – Gross Combined Mass
Gross Combined Mass is the total weight of towing vehicle and, trailer or caravan, a maximum as determined by the manufacturer.
This may be increased by a licensed certifier (yes Greg is one) in some cases on modified vehicles.
GTM – Gross Trailer Mass
Gross Trailer Mass is the weight a trailer transmits to the road via the wheels.
This can be increased on most trailers and caravans depending on spring rates and Axle Group Capacity and/or modification.
ATM – Aggregate Trailer Mass
Aggregate Trailer Mass is the total weight of the trailer of caravan when fully loaded. This is the GTM (see above) plus tow ball weight.
The ATM can be increased on suitably modified vehicles and can be limited by things like:
- Tyre rating
- braking capacity
- axle group capacity
- spring rate
- chassis design/construction
- tow coupling capacity
- safety chains
Note: For trailers and caravans the weight listed on registration documents as GVM is ATM.
How can Johanson Brothers Motorsport help you?
We can inspect and assess your individual application and provide guidance and advice on the best course of improvement to your vehicle to increase load carrying capacity and safety. We provide tested, engineered and compliance solutions.
Caravan ATM upgrade
Our range of custom caravan springs are developed with Kings springs to provide superior ride, stability and correct suspension alignment and travel on heavily loaded vans.
Call Greg on 0412 666658 to discuss what options may be available to improve the ride, safety and legality of your vehicle.