Is your caravan’s compliance plate lying to you?


The trailer plate, often misleadingly referred to as the compliance plate, is an important part of a caravan or camper-trailer, but is your compliance plate lying to you?

The intent of fastening trailer plate to a vehicle is to provide assurance from the manufacturer – to vehicle registration authorities and the purchaser – that the vehicle is fully compliant with all prescribed legislation and as such it is ready for use on Australian roads. Sadly, for far too many caravans, this is clearly not the case.

Vehicle Safety Standards has stated that all information provided on a trailer plate must be:

  • Legible
  • True
  • Correct
  • Accurate
  • Complete

Actual Masses such as Tare Mass and Empty Ball Loading must be physically measured, by scales or on a weighbridge that is certified and has been independently checked for accuracy, as prescribed in the licencing contract. The Tare Mass and Empty Ball Loading measurements must be made when the caravan (including water tanks and gas cylinders) is completely empty, and fitted with all equipment that is specified on the sales contract.

The legal significance of an assurance needs to be clearly understood. Negligence, ignorance and assumption are not defences for stating any information that is not in strict accordance with the requirements. Needless to say, stating any information that is fraudulent is a very grave matter.


Compliance Plate
Old school compliance

The trailer plate must show at least the following information:

  • Manufacturer’s name
  • Caravan model
  • Vehicle Identification Number (17-digit)
  • Date of manufacture (month/year, e.g. 08/20)
  • Aggregate Trailer Mass (ATM) rating
  • Certification Statement: “This trailer was manufactured to comply with the Motor Vehicle Standards Act 1989”

Basic compliance plate info

The trailer plate may also include additional information, such as that required for the tyre placard. Masses and Ratings must be stated in kilograms (kg). Tyre inflation pressures must be stated in kPa (not psi).

The full specifications of the wheels (diameter, width and profile) and tyres (diameter, section ratio, width, and type [P/C/LT]) must be stated so that there is no guessing required to determine the complete specifications.

In addition to the information that is required by VSB1 (Vehicle Standards Bulletin No.1), it is most prudent to advise additional information that may very well be deemed to be “information required by the owner/driver, so as to best ensure that the tow vehicle and caravan are loaded and used in a safe and legal manner”.

This information includes the:

  • Gross Trailer Mass (GTM) Rating
  • Axle-Group Rating
  • Empty Ball Loading

The Gross Trailer Mass (GTM) Rating is needed to confirm what braking system is required… is it above or below 2000kg?

The Axle Group Rating and the Gross Trailer Mass (GTM) ratings are needed – for non-load-sharing suspension systems – to confirm if the 120% safety factor has been incorporated in the design of the suspension system.

The Empty Ball Loading is needed to ensure that the caravan is suitable for the intended tow-vehicle. It will also assist in correctly loading the caravan so that load-distribution (in a side view) does not cause any rating to be exceeded, or the caravan to develop hazardous handling and stability problems on the road.

It is recommended that the offset – plus or minus ‘X’ mm – of the wheels be added so that if aftermarket wheels are fitted, the same offset can be selected, so as to avoid having the tyre’s sidewalls foul on any chassis or body component, which can readily cause dangerous blowouts.

It is important to know that the allocated GTM Rating has been properly determined by the manufacturer.

Unfortunately, many people continue to use the incorrect ‘old husbands’ tale’ or either of these two equations:

Empty Ball Loading = ATM Rating – GTM or GTM Rating = ATM Rating – Empty Ball Loading

This is completely wrong because there is no logical relationship involved!

The ATM and GTM are fixed ratings allocated by the manufacturer, in relation to the maximum-permissible All-up and Axle(s) limits.

The Empty Ball Loading is an actual mass that must be measured and is obviously applicable only to the empty (Tare Mass) condition.

The correct formula is, at any time: Actual Ball Loading = All-up Mass – Axle(s)-Loading

It is essential that all caravan buyers fully understand all of the information that is provided by the manufacturer on the trailer plate, before they accept the caravan, in order to avoid possible major problems in the future. You should obtain a copy of the certified measurements of the Tare Mass and the Empty Ball Loading.

If you have any questions about any items on the trailer or compliance plate, it is important to have the dealer provide a concise and credible explanation. That way, if your compliance plate is lying to you, you have the opportunity to sort it out there and then. Not later. And not in court.

Thanks to Colin Young of the Caravan Council.

Read next Caravan weight check: How do your numbers stack up?




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