Payload: How To Re-register Your Caravan’s Tare & GVM

Words Godfrey Castle & Francois Huysamen

This might come as a surprise to many readers: did you know that you can increase the payload of your caravan or trailer?

By law, a caravan must have a minimum payload of 15% of the Gross Vehicle Mass (GVM). But, without realising it, almost two out of every three caravanners overload their caravans. This is usually because they do not know that any installations or modifications made to the caravan eat into their payload. However, you can re-register your caravan or trailer’s Tare to include the weight of these installations.

Here are the definitions for the terms used in the article:
Gross Vehicle Mass (GVM) is the Maximum mass the caravan/trailer is allowed to have, including the payload.
Tare is the weight of the caravan/trailer when not loaded, and includes the spare wheel, equipment supplied by the manufacturer as standard, and anything attached to the caravan/trailer so as to form a structural alteration of a permanent nature.
Payload – The difference between the GVM and the Tare of the caravan/trailer.
Gross Combination Mass (GCM) – the combined GVM of the tow vehicle and the caravan/trailer being towed.

Determining Tare & GVM

The Tare of a caravan or trailer is first determined by the design of the manufacturer, and usually does not include items such as an aircon, tents or awnings, park-assist systems, an extra battery, etc.

The manufacturer then determines the GVM by applying the 15% rule for payload. However, this registered figure may be less than the actual possible maximum GVM of the unit, which is determined by the ratings of the axle, brakes, coupler, rims and tyres.

The reason that manufacturers don’t register caravans or trailers at their maximum legal GVM is for two important considerations:
• The Gross Vehicle Mass (GVM) of the caravan/trailer must not exceed the Tare of the tow vehicle.
• The Gross Combined Mass (GCM) of the tow vehicle must not be exceeded.

In other words, if a caravan’s GVM were always registered at maximum, many of us with lighter tow vehicles might not legally be allowed to tow!

Increasing payload

If you’ve added any (permanent) items to your caravan or trailer, their weight has not been added to the registered Tare on your licences. You can re-register your caravan or trailer with the new Tare… but that won’t increase your payload, as you will still have the same GVM. The fact that your new payload now does not comply with the 15% rule is of no consequence – you can’t be fined for that.

However, you can also re-register your caravan or trailer’s GVM, increasing it up to the maximum within the load regulations of the axle, brakes, coupler, rims and tyres. This will, in turn, increase your payload! Because maximum payload is dependent on various factors, it is best to have a manufacturer determine it.

VERY IMPORTANT: If you re-register your GVM, make sure that the Tare of your towing vehicle is more than the new figure you are registering.

Why this matters to the police

If you overload your caravan or trailer, you will be fined. That is simply your fault. If your tow vehicle is too light for your caravan or trailer, you will be fined. That is simply your fault.

So, why would the police want you to re-register your higher Tare and GVM? That’s simple: because licence prices are determined by Tare. The higher the Tare of your caravan or trailer, the more your licence costs.

How to re-register

Providing that certain criteria and components are still within load limits, you can initiate the process of having the Tare and GVM of your caravan and trailer updated.

Jurgens Ci (Campworld) has compiled a document on this process:

How to change a caravan/trailer Tare and GVM.

New Tare

The caravan/trailer needs to be weighed at an accredited weighbridge to determine the new Tare. An official weighbridge certificate must be obtained. Tare is the unladen weight of the caravan/trailer. Tare will include all standard equipment (like tents, tent poles, tables, spare wheel, gas bottles etc.) and any other aftermarket fitments (like movers, air-conditioner units, etc.) Tare excludes items which are not part of the caravan/trailer, such as food, clothing, water, gas, other camping gear, etc.


The new GVM must exceed the Tare and can be set as high as the axle rating of the axle fitted to the caravan/trailer. Attention must be given to the fact that the law requires that the tow vehicle Tare be equal to, or higher than, the GVM of the caravan/trailer.

Another factor to take into account is that your tow vehicle is also restricted to its allowed GCM. If the caravan/trailer axle has been changed to a higher rating, then the coupler, brakes, rims and tyres must also be rated for the new GVM, and not only the suspension.


The caravan/trailer must then be taken for a roadworthy test at an accredited testing station. The official weighbridge certificate displaying the new Tare must accompany the vehicle. The testing station must provide a roadworthy certificate and an official document stating that the Tare and GVM of the caravan/trailer have changed from that which is indicated on the caravan/trailer’s data plate.

Licensing Authority

A CNV form must be completed and taken to the local licensing authority along with the following documentation:
• A copy of NATIS (the vehicle registration certificate)
• A copy of the owner’s ID
• Proof of address
• The roadworthy certificate
• A letter from the roadworthy testing station, affirming the new Tare and GVM
• A weighbridge certificate

The licensing authority will process this information and update their system.

Please note that this may take some time, as the documentation has to be circulated to various departments. Once it has been approved, the licensing authority will issue a new licence disc reflecting the new Tare and GVM.

A new registration certificate should also be obtained. However, if the caravan/trailer is financed, then the new registration certificate will be issued only once the caravan/trailer is settled and title transferred to the owner, or when the caravan/trailer is sold.

Manufacturer data

A new data plate which reflects the new updated Tare and GVM must be obtained for the caravan/trailer. This can be ordered from any Campworld Dealer.

Please provide copies of the new licence document, your ID, and proof of address. Once the new data plate has been made, it will be sent to the relevant Campworld dealer, who will contact the
customer and exchange the new data plate for the old one.

The new data plate must be fixed to the A-frame of the caravan/trailer. The estimated cost of this process is in the region of R1 500.

Note that the final cost is subject to variables such as:
• The expiration date of the caravan/trailer’s current licence disc,
• The new Tare moving into a higher licensing-fee bracket, and
• The amount charged by the testing station.

Click here to see the documents that you are required to complete at your motor vehicle registration authority.

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