During the holiday season, the space available for family cars quickly reaches its limits. Then a roof box can help. But only if you keep an eye on the weight. Otherwise you risk a fine or even points in Flensburg.
It's not that easy to determine how much weight you can put on the roof of the vehicle and how many kilos you actually have on it after packing. The vehicle registration document only provides information about the permissible total weight under the letter "F" and about the curb weight under "G". The difference results in the permitted payload weight. The roof load is part of this weight.
Maximum roof load mostly between 50 and 100 kilograms
But that doesn't do the driver much good at first, because he doesn't know how much weight he can put on the roof. If you want to know exactly, you need the operating instructions. The permissible roof load is noted there. According to TÜV Süd, the value is between 50 and 100 kilograms, depending on the manufacturer and size of the vehicle.
It is important that the driver adds up the weight of the roof box and the roof rack as well as the weight of the contents.
Example: If the box weighs 15 kilograms and the roof rack weighs 5 kilograms, the driver is only allowed to pack 80 kilograms of payload with a maximum roof load of 100 kilograms.
And of course you have to keep an eye on the permissible total weight of the car. If that is maxed out down to 30 kilograms, for example, less can be put into the loading box, even though the maximum roof load may not have been reached yet.
Many roof racks specify a higher payload than the car manufacturer specifies for its model. If damage occurs, the causal chain of possible determination of guilt begins with the maximum roof load according to the car manufacturer. Thus, in the event of damage, the insurance cover for the vehicle driver may expire.
85 percent of the roof load acts on the rear axle
But not only the permissible total weight is decisive for correct loading. The axle load also plays a role in the permitted weight. Like the permissible total weight, the axle load can also be found in the vehicle registration document, here under the letter "L". According to ADAC, 85 percent of the roof load acts on the rear axle of the car. This means that the weight on the roof even has an effect on handling, because it shifts the vehicle's center of gravity up and further back.
Maximum loading or even overloading also increases the braking distance, evasive maneuvers become more sluggish and the ADAC points out that the car can start to sway despite ESP. It is therefore very important how drivers distribute the weight in the roof box. About half of the weight should be in the center of the box. The other two quarters are ideally placed in front of or behind. To ensure that the luggage does not slip, the driver should secure the load using eyelets and straps.
Points in Flensburg
Anyone who does not load properly or even overloads pays a fine in case of doubt and, depending on the case, must reckon with points in Flensburg. A fine of between 10 euros and 235 euros is due from a 5 percent overload. If 20 percent overload is reached, the driver earns additional points for his account in Flensburg.
Roof racks for boxes or other structures are practical and useful, because after all, you don't need that much space all year round. But using it has astonishing pitfalls: the driver has to find out all the details beforehand in order not to exceed the roof load – which is not at all easy. The ADAC even recommends weighing the roof luggage. In practice, this may not be possible for everyone.
Drivers should also distribute the weight correctly so that driving behavior does not suffer too much.