Trailer Specs Explained: What New Owners Need to Know About ATM, GTM and More
Confused by ATM, GTM, GVM and payloads? Here’s what they really mean
At Basic Trailers in Adelaide, we’ve found that one of the biggest sources of confusion for new trailer owners is the technical jargon around trailer specs.
If you’ve come across acronyms like ATM, GTM, GVM and terms like payload but aren’t quite sure what they mean or why they matter, you’re not alone.
Understanding these specs is crucial for safe towing, legal compliance and getting the best out of your trailer.
In this guide we’ll explain what each of these specs means, how they relate to each other and why they should influence your trailer buying decision.
What are ATM, GTM, GVM and Payload?
Aggregate Trailer Mass (ATM)
ATM is the total weight a trailer can carry when it’s fully loaded and not connected to a vehicle. It’s the tare weight (empty trailer) plus the maximum cargo load.
For example if a trailer’s tare weight is 600kg and its load capacity is 1400kg, its ATM would be 2000kg.
Choosing the right ATM is important. At Basic Trailers we have a range of trailers with different ATM ratings to suit your hauling needs—whether you’re carrying building materials, machinery, vehicles or other loads.
Gross Trailer Mass (GTM)
GTM is the weight of a fully loaded trailer when it’s connected to a tow vehicle. It’s generally less than the ATM because some of the load is transferred to the vehicle through the tow ball.
This figure is important for selecting the right suspension and axle configurations.
Gross Vehicle Mass (GVM)
GVM is the maximum weight your tow vehicle can legally carry, including passengers, cargo, fuel and the weight from the trailer’s tow ball download.
Exceeding your vehicle’s GVM not only attracts fines but can also compromise braking and steering performance.
Payload
Payload is the weight of the cargo you can legally and safely carry in your trailer. It’s the trailer’s ATM minus the tare weight.
For example if your trailer’s ATM is 2000kg and its tare weight is 750kg, your payload is 1250kg. Always make sure your load fits within the payload limit to tow safely.
Trailer suspension and ATM – matching the right specs
Choosing the right ATM rating also means choosing the right suspension system. As we discussed in our blog on trailer suspension options, lighter trailers (ATM under 2000kg) may be well suited to slipper or eye-to-eye spring suspension, whereas load sharing rocker roller suspension is often ideal for heavier loads and tandem axle configurations.
For example if you’re carrying uneven or heavy loads, trailers in Adelaide for Australian conditions. Whether you’re after a tough tandem box trailer or a purpose built flat top car trailer, your intended use should guide your choice of trailer and specs.
Our guide to tandem trailers explains that tandem axle trailers, especially those with ATM ratings of 2000kg or more, are ideal for heavy duty work, greater stability, better braking and more payload.
We have a range of tandem trailers with different ATM ratings to suit your towing needs. Whether you need a trailer for landscaping, trades or vehicle recovery we can help you choose a configuration that fits your budget and hauling requirements.
Is your vehicle up to the task?
Understanding your trailer specs is only half the story—you also need the right towing vehicle. As we explained in our blog on choosing the right tow vehicle, factors like braked towing capacity, GVM, GCM (Gross Combination Mass) and tow ball download limits all come into play.
Always check your vehicle’s compliance plate or owner’s manual to make sure it can legally tow your chosen trailer at full load.
Helpful towing tips
1. Never exceed your trailer’s ATM or your vehicle’s tow capacity.
2. Distribute your load evenly to reduce sway and wear.
3. Invest in quality trailer brakes and make sure your suspension is up to the task.
4. Keep up with maintenance, especially axles, brakes and couplings.
5. Know the local road rules, including speed limits for towing.
Talk to Basic Trailers and get towing today
As specialist trailer manufacturers, we’re here to help you make the right choice for your towing needs and your vehicle.
Get in touch with us on 1300 770 770, or email us with your enquiry, and a member of our team will be happy to answer any questions you may have about trailer ATM, GTM, GVM and payloads.
