Many car owners want to customise or individualise their vehicle to suit their own tastes. There are a number of ways to do this, though they are not endless. They range from simple decorative strips to sophisticated engine tuning.

The application of decorative strips to the bodywork is a purely visual change with no technical significance. However, many customisations (tuning measures) change the driving behaviour of the vehicle and affect its handling. They also affect the safety of all road users.

Checking the freedom of movement of the wheels when changing the wheel/tyre combination and/or chassis.

The most popular tuning modifications include changing the wheel/tyre combination or fitting special wheels. Another popular modification is to the suspension, which can be done to change the handling of the vehicle as desired. Spoilers are also very popular. They can affect driving behaviour, cornering ability and ultimately downforce and braking performance.

What do you have to do to be on the safe side when tuning?

First of all: for many tuning measures, either the proof of their legality in the general operating licence (ABE) must be carried or a vehicle inspection must be carried out and verified, which refers to the modification to the vehicle. This can be an individual inspection according to § 19.2 in conjunction with § 21 or an inspection of modifications according to 19.3 of the Road Traffic Licensing Regulations (StVZO).

Installation or modification of air deflectors (spoilers) to measure the effect on lift or downforce.

And: these vehicle inspections may only be carried out by experts with the appropriate qualifications. Depending on the inspection, this may be a test engineer from an officially recognised vehicle inspection organisation (e.g. KÜS), an authorised signatory of a technical service or an officially recognised expert (aaS). The law precisely regulates when which of these persons may become involved in such cases.

The importance of the test certificates (e.g. ABE or parts certificate) is often underestimated. The installation of parts that could lead to a hazard will invalidate the vehicle's operating licence. Note: It does not expire if there is a valid test certificate for this modification to this vehicle and a possibly required modification acceptance (§ 19.3 StVZO) is carried out. If there is no valid test certificate or the conditions of the test certificate are not complied with, an expert opinion can be prepared to obtain an individual operating licence. With the expert opinion to obtain a new operating licence, the tuner must now go to the responsible registration office. This office will now issue a new operating licence for the tuned vehicle.

So: vehicle tuning, making changes to the vehicle to your own taste, should be fun, of course! But it must also be safe and in accordance with the rules. And all of this fits together perfectly! The KÜS will be happy to assist you with any questions you may have about tuning, so that you are on the safe side in every respect.

You can easily find a KÜS partner near you on the Internet at www.kues-fahrzeugueberwachung.de/standortsuche.