Some important definitions

I recently picked up that a friend was confused with terminology related to his 4×4. It was easy to sort out, the possible impact of the confusion could have had implications.

He was of the impression that he could tow a large off-road trailer with a code E license. In 2000 the government moved to credit card licenses and converted all code 08 licences to EB licenses. Subsequently, all new licenses were issued as code B. The implication thereof is that;

• Code B; allows you to tow a light trailer weighing no more than 750 kilograms fully laden.
• Code EB: allows you to tow a trailer, boat or caravan exceeding 750 kilograms.

Towing more than 750 kilograms without a code EB license is thus illegal and a contravention of the Road Traffic Act. One cannot upgrade to a code EB license. You will have to take a test and qualify with a trailer weighing more than 750 kilograms.

I brought this up as they affect another area where he was confused, that of payload. Let’s unpack the terms related to weight, as this is where you can fall foul of the law if pulled over onto a weigh-bridge.

People often see payload as the amount of weight you can carry in the load bin or cargo compartment. Yet payload is the maximum mass (weight) the vehicle, caravan or trailer may carry including passengers, fuel and cargo.

Going back a step let’s look at your vehicle as you purchase it. Tare is the weight of the vehicle as it comes off the assembly line with 10 litres of fuel. Kerb weight is the vehicle parked with a full tank of fuel. The next measurement would be Gross Vehicle Mass ( GVM ), this is the total of the kerb mass and the payload  –  the maximum permissible loaded mass (weight) of the vehicle.

That would bring us to the Gross Combination Mass, the total mass of the vehicle ( GVM )  and the maximum weighted towing capacity of the vehicle with a trailer or caravan as specified by the manufacturer.

Why is this important you may ask? Well, it is all about the specifications of your vehicle and your warranty. Everything is designed to work within these parameters. So this is important when you add weight. Think Jerry cans, water tanks and accessories such as replacement bumpers and rear bumpers, also look at the weight of a roof-top tent.

Critical components in your vehicle are designed to operate within specific tolerances, even tyres can be affected by exceeding the load index ( weight carrying capacity of the tyres stated on the sidewall ). Excessive overloading can affect your stopping distance when braking. Overheating the brakes could cause brake fade, a reduction in stopping power. You need to consider suspension components such as shock absorbers which will fail if they overheat. Overheating could also take place in your cooling system and transmission. Weight adds up quickly, add in a full tank, four adults, a winch and replacement bumper and you are soon getting close to overloading and stressing components. A failure could be costly if a manufacturer voids a warranty claim or if you are fined en route to your holiday destination. If you are buying a new vehicle work with your dealer and fitment centre. Fit approved accessories to avoid component failure and the rejection of a warranty claim