Under the current VSB1, a low-ATM trailer must carry a durable, permanently attached vehicle plate showing the manufacturer or make, the 17-character VIN, ATM, GTM and tare. The mandatory values must match the trailer’s Register of Approved Vehicles entry.
People still commonly call it a compliance plate, but the current government documents use “vehicle plate.” The label matters less than checking that the physical marking, digital RAV record and actual trailer all agree.
Mandatory information
VSB1 Revision 6, August 2026, lists these mandatory details:
| Plate field | What to check |
|---|---|
| Manufacturer’s name or vehicle make | Matches RAV and vehicle identity |
| Vehicle Identification Number | Complete, unique 17-character VIN |
| Aggregate Trailer Mass | Maximum total loaded trailer mass when uncoupled |
| Gross Trailer Mass | Maximum mass carried through trailer tyres when coupled |
| Tare mass | Recorded unladen reference mass |
The plate may also include tyre information, model and build date. “May” matters: those optional fields should not be presented as mandatory VSB1 plate content.
How the plate must be made and attached
VSB1 says the plate must be durable and permanently attached, giving welding or riveting as examples. Information must be embossed, indented, etched or engraved, in English, using block letters and numerals at least 2.5 mm high.
A loose sticker, handwritten alteration or plate that can be removed without evidence deserves investigation. Do not repair, restamp or replace vehicle identity markings yourself without authoritative guidance.
The plate must be legible enough to compare. Clean it gently without destroying markings and photograph it straight on.
Why the RAV comparison matters
The government’s RAV guide explains that trailers require a digital RAV record and a physical plate. VSB1 says mandatory plate details must match those entered on the RAV and notes that an offence occurs when an actual vehicle specification, such as tare, does not match the details entered.
Search the VIN on the official public RAV. Compare characters, make/model context and mass fields. Follow the RAV checking process rather than relying on a seller’s screenshot.
A RAV match confirms the record associated with the VIN. It does not inspect the current condition or prove that later modifications are compliant.
Read the mass fields correctly
ATM, GTM and tare are different. ATM includes the coupling share of the total trailer when uncoupled; GTM describes the portion carried by trailer tyres when coupled; tare is the defined unladen reference.
Use the full ATM, GTM and tare guide before calculating capacity. The plate’s figures are limits or recorded specifications, not a weigh ticket for the current trip.
The tyre placard and component markings add other limits. Never assume ATM is the only number that matters.
Optional tyre information
VSB1 allows tyre information to appear on the vehicle plate, but it also sets tyre-placard requirements. Check designated tyre size, recommended cold inflation pressure, load capacity and speed category against the actual tyres and the current document.
A tyre with the right diameter can still have an inadequate load rating. Replacements must be suitable for the trailer and fitted under applicable requirements and manufacturer advice.
Warning signs for buyers and owners
Investigate when:
- the plate and stamped VIN disagree;
- fewer or more than 17 VIN characters appear;
- the RAV returns another vehicle;
- ATM, GTM or tare differs between plate and RAV;
- values look overwritten or a second plate covers the first;
- a make or model is inconsistent with documents;
- modifications would plausibly change a recorded specification;
- the plate is missing or not permanently attached.
Do not accuse a seller based on appearance alone; plates can be damaged and records can contain correctable errors. But do not complete a purchase until the competent authority or manufacturer explains and documents the discrepancy.
Modifications and tare
A battery bank, water tank, spare carrier, kitchen or suspension change can alter actual mass and component loads. Whether it requires a plate, RAV or registration change depends on the modification and applicable pathway.
Keep invoices, specifications, engineering certificates and weigh records. If the actual specification no longer matches the official record, seek advice from the manufacturer, a licensed certifier and the registration authority rather than choosing a new number yourself.
A five-minute plate audit
- Locate the physical vehicle plate.
- Photograph it and the secondary VIN marking.
- Transcribe the VIN independently from each location.
- Record ATM, GTM and tare.
- Search the VIN on the public RAV.
- Compare every mandatory detail.
- Compare tyre and coupling markings.
- List modifications made since the recorded configuration.
- Escalate mismatches before towing, purchase or registration.
What the plate does not prove
It does not prove roadworthiness, gas or electrical safety, ownership, finance status, recall completion, current registration or actual loaded mass. Those need separate checks.
For a used purchase, separate the checks into three files. The identity file holds the plate, VIN and RAV result. The condition file holds inspection and service evidence. The ownership file holds registration, seller and financial-interest checks. Keeping them separate makes it harder for one clean official record to create false confidence about an unrelated risk.
Owners should repeat the plate-to-RAV comparison after any approved rating change and before advertising the trailer for sale. Provide the buyer with the complete correction or engineering trail rather than only the newest label. If an insurer or registration authority asks for a rating, supply the authoritative document and current record, not a number transcribed from memory.
The plate is best understood as the physical identity-and-rating anchor for the trailer. When it is durable, legible and consistent with the RAV, it gives owners a reliable basis for the next step: measuring the real combination and respecting every lower component limit.