'Grossly incorrect ratings and masses'

Caravan manufacturers accused of giving misleading information on plates

Compliance plate Have your say

CARAVAN Council of Australia founder Colin Young has fired a broadside at RV manufacturers over misleading information on compliance plates.

The professional engineer claims that up to 90 percent of plates fitted to caravans and camper trailers give false or incomplete information, particularly when it comes to ratings and masses.

"The main and most serious problem is that many, for one reason or another, often contain grossly incorrect information which has significantly contributed to a disturbing number of problems, complaints and litigation issues," he said.

Misleading tare mass and empty ball-loading figures were the most common issues.

Mr Young said plates were fitted by manufacturers to provide an assurance to vehicle registration authorities and the buyer that the vehicle was 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," he added.

Mr Young has put together the following article:

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


Actual masses tare mass and empty ball-loading must be physically measured by scales or a weighbridge that is certified, and has been independently checked for accuracy as prescribed in the licensing 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 specified on the sales contract.

The legal significance of an assurance needs to be clearly understood.

Negligence, ignorance and assumption are not defences for giving any information that is not in strict accordance with the requirements.

Stating any information that is fraudulent is needless to say a very grave matter.

The trailer plate must show at least the following information:

Manufacturer's name
Caravan model
Vehicle identification number (17-digit)
Date of manufacture (month and year ... example: 08 - 20)
Aggregate trailer mass (ATM) rating
Certification statement: example: This trailer was manufactured to comply with the Motor Vehicle Standards Act 1989.

The trailer plate may also include additional information, such as that required for the tyre placard.

Masses and ratings must be stated in 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 there is no "guessing" required to determine the complete specifications.

In addition to the information 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 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 (AGR) and the Gross Trailer Mass (GTM) rating are needed for non-load-sharing suspension systems to confirm if the 120 percent safety factor has been incorporated in the design of the suspension system.

The empty ball loading is needed to ensure the caravan is suitable for the intended tow vehicle, and to 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 to avoid having the sidewalls of tyres foul on any chassis or body component, which can readily cause dangerous blow-outs.

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 husband's tale" or "equation" that:

Empty Ball Loading = ATM Rating - GTM Rating 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 the information provided by the manufacturer on the trailer plate before they accept the caravan so as to avoid possible major problems in the future.

It is most prudent to 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 plate, it is important to have the dealer provide a concise and credible explanation.


 No part of this publication may be reproduced or transmitted without
the prior written permission of Dennis Amor.

Copyright 2005 Dennis Amor
All Rights Reserved

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