Towbars used in Europe are standardised in several key areas. This means every towbar manufacturer must adhere to specific legal agreements: the towbar has a diameter of 49.61-50 mm, and the towbar neck has a diameter of 27-29 mm. These dimensions allow towbar bike carrier manufacturers to offer a universal bike carrier.

However, there are a few exceptions. A number of special “towbar bike carriers” are in circulation, which may only be used in combination with a bike carrier. They cannot be used to tow a trailer or caravan, so strictly speaking, you cannot really call them a towbar. Since hybrid car drivers still like to use a bike carrier, and this is permitted, various towbar manufacturers have devised solutions, each designed differently depending on the brand.
Apart from whether the towbar bike carrier fits on the towbar (which will be the case 98% of the time), it is crucial to respect the maximum noseweight of the towbar. This noseweight (vertical load) is stated on the towbar's identification plate, is included in the type approval, and must not legally be exceeded. The towbar's identification plate can usually be found next to the electrical socket; if not, consult your car dealer. At present, the towbar's noseweight is the only reference regarding the maximum loadable weight for the towbar when using a bike carrier.
Officially, this is not entirely correct (this is currently being worked on at a European level), but to date, it remains the only legal reference and must be respected. This maximum noseweight, as well as the towing capacity, has been determined by the car manufacturer and the towbar manufacturer based on many factors, such as how the towbar is attached to the car, the car's chassis, engine power, suspension, and handling characteristics. Furthermore, a towbar is subjected to heavier loads when used in combination with a towbar bike carrier than when towing a trailer. It is therefore very important to know whether the car on which the bike carrier and bikes will be used is actually suitable. Many popular smaller cars only have a noseweight limit of 50 kg, which puts the transport of two electric bikes in the danger zone. The weight of most electric bikes can be reduced by removing the bike battery (where possible).
PLEASE NOTE: when determining the maximum noseweight load, the weight of the bikes as well as the weight of the bike carrier itself must naturally be added together!