When establishing a stable combination for your tow vehicle and caravan/camper trailer, it is important to understand tow ball weight.
Tow Ball Weight
Tow ball weight, also referred to as tow ball mass, is the weight pushing down on the tow ball by the coupling of the RV being towed.
Maximum tow ball weight is specified by both the vehicle and trailer manufacturer. Typically, it is 10% of the Aggregate Trailer Mass (ATM). You must use the lesser of the two limits.
For example, a dual cab ute with a maximum tow ball weight of 350kg towing a caravan with a maximum tow ball weight of 220kg must not exceed 220kg.
Tow ball weight is best checked with tow ball weight scales which can be purchased from reputable auto and RV stores. Vehicles can also be weighed at public weigh bridges or by a mobile weighing company.
How you pack your caravan/camper trailer greatly affects the tow ball weight.
If you have more weight closer to the tow vehicle, you will have a high tow ball weight, and this will affect the vehicles handling. You may even be able to see this as the car will be raised at the front axles and the whole combination will dip in the centre.
Common causes of high tow ball weight are tool and storage boxes added onto the trailers A-Frame.
If you place too much weight at the back of your caravan/camper trailer, you will have a light tow ball weight. This is likely to cause caravan sway. You can learn more about caravan sway here.
Additional storage boxes and bikes mounted to the back of the trailer can cause excess weight at the rear and therefore lighter tow ball weight.
It is ideal to pack heavy items low and centrally as possible.
Medium weight items should be stored below window height. The lightest items can be stored in the overhead lockers. It is also a good idea to check where the caravans water tanks are located. When full, these can significantly affect the tow ball weight and your combination’s stability on the road.
Your tow ball weight counts as part of your Gross Vehicle Mass when towing, so it is best to keep this in mind to ensure your vehicle is not overloaded. Typically, the tow ball weight should be 10% of the trailer’s laden weight.