A Guide With the Most Common Trailers Terms

Buying a trailer for the first time can be a challenging experience, mostly because of not knowing the specific terminology. This is a guide with the most common terms.

Aggregate Trailer Mass (ATM) refers to the total trailer weight, composed of the trailer weight that is not coupled to a towing vehicle and the total weight of the load. Otherwise, Gross Trailer Mass (GTM) is the total weight of a fully loaded trailer, which is coupled to a towing vehicle. This means GTM will always be less than ATM because part of the towed vehicle weight is transferred to the towing vehicle.

Coupling is the connection between the trailer and the towing vehicle. There are many types of couplings, depending on the loaded weight that has to be towed and the conditions of the towing.

Gross Combined Mass (GCM) as its name says is a maximum combined weight of a vehicle, the passengers, the trailer weight and the load weight. The maximum allowable rate is set by the vehicle manufacturer. Also known by the following terms: Gross Combination Weight Rating (GCWR), Gross Train Weight (GTW) or Gross Combined Weight (GCW).

Gross Vehicle Mass (GVM) is the maximum weight of a vehicle, including the vehicle's chassis, body and engine, all the passengers and the cargo. It is obvious the trailer weight is not included in the GVM.

Single Axle Trailer is having one axle attached, with two connected wheels. Specifically for this type is that it can drag a certain weight of a load. On the other hand, Tandem Axle Trailer is having two axles. The total number of wheels is 4. More wheels mean greater stability, so these trailers are excellent for dragging heavier load. It is also known as Dual Axle or Double Axle.

Safety Chains are attached to the trailer, allowing it to remain connected to the towing vehicle in case of their disconnection. They have to be checked every time a trailer is towed.

Tare Mass refers to the empty weight of a trailer. Usually, this weight is stamped on the trailer itself, by the manufacturer.

A Payload is the maximum allowable weight of the load that a trailer is designed to carry. It is the difference between its Tare Mass and its ATM.

VIN is a vehicle information number, containing 17 characters. A trailer is identified by that unique number. Some states in Australia require the VIN to be stamped on the trailer.

Weight Distribution System is a system that increases the towing capacity of a trailer, by improving the handling and braking. The system is located around the couplings, including additional equipment.