ATM, GTM and Tare Mass Explained

Question:

I am endeavouring to understand the difference between the ATMfoot of my van and the axle group load capacityfoot of my van. The van is a 2000 Regent Cruiser pop top van 16.5 footer with a specified ATM of 1670kg, GTM 1450, Tare Mass 1265 and Axle Group Load Capacity of 1600. I have loaded it up and the total ATM is 1592kg at the weighbridge - within both limits but close to the axle load capacity and we would probably want to add another 5 - 10 kg food etc if allowable - hence my dilemma . The Tow ball weight is around 148kg. How can I calculate or measure the axle load? Is it a combination of, or ratio of the ATM and the tow ball weight? Thanks

asked by: David B

Expert Reply:

ATM is the maximum mass the towing vehicle can tow (mass of vehicle plus load in the trailer). Aggregate trailer mass is what it stands for.

GTM stands for gross trailer mass, which is the total mass of the trailer fully loaded. (Mass of trailer plus maximum load the trailer can carry.)

The ATM minus the mass of the trailer is the maximum load you can legally put in the trailer regardless of the carrying capacity of the trailer.

Tare mass is the weight of the vehicle without anything loaded, so in your case your Regent Cruiser weighs 1,265 kg unloaded. Your axles have a load capacity of 1,600 kg.

If you are right at capacity without the trailer loaded as well then you are good to go, if the tare mass of the setup plus the tongue weight of the trailer is above the axle capacity you will need to lighten your load a bit before you can safely tow your setup.

expert reply by: Jameson C