Discover Your Vehicle’s Perfect Tyre Size with COC

Many drivers want to change the tyres on their vehicle to improve its appearance. But in most cases, one question arises: Which tyres am I allowed to drive? The permitted tyre size can be found in the COC papers. Under certain circumstances, however, it is also possible to use a different tyre size than the one entered in the vehicle registration document or the EC certificate of conformity. We tell you what you need to look out for.

What is the significance of the COC documents?

The so-called COC papers (for ‘Certificate of Conformity’) are proof that the vehicle in question meets the applicable requirements and standards of the EU and is therefore approved for registration in Europe. Officially, these documents, which car buyers receive with every new car, are referred to as an EC certificate of conformity or EU type approval. All technical features and data of the vehicle are noted in the COC papers, i.e. not only the manufacturer and model, but also the dimensions, weight and emission values – as well as the permitted tyre size.

The most important information on tyre sizes at a glance

– Approved tyre sizes are listed in the COC papers

– Vehicle registration certificate (registration certificate part I) also provides information

– Example of a typical tyre size: 205/55 R 16 91 V

– COC papers not available? EUROCOC can help!

– Only drive with an approved tyre/wheel combination!

All information on tyre size in the COC papers

The COC papers show which tyres may be fitted to the respective vehicle. However, it is important to find the information and interpret it correctly. By the way: If you do not have COC papers for your vehicle, you can apply for the document via EUROCOC! There is no COC database for the tyres so that you can look them up directly.

Find the tyre size in the COC papers: Where does it say?

Where the tyre size can be found in the COC documents depends on the manufacturer. It is often under points 32, 35 or 50, where all permissible wheel and tyre sizes for the front and rear axles are noted. It is possible that the tyre sizes can be found under two different points – in this case, the tyres with which the vehicle is delivered and the alternative tyre sizes that are also permitted.

Tyre size not in the vehicle registration certificate – but in the COC papers

When a new vehicle is registered and the registration certificate part I (vehicle registration document) is issued, the data and technical characteristics are taken from the COC papers. As a rule, this is the tyre size that is fitted on delivery. This means that not all permissible tyre/wheel combinations may have been transferred to the vehicle registration document. It is therefore possible to have the approved tyre sizes from the type approval subsequently entered in the vehicle registration document!

What if the tyre size is not in the COC papers?

If the desired tyre size is not noted in either the vehicle registration document or the EC certificate of conformity, this does not mean that drivers are generally not allowed to drive these tyres. However, individual approval by a recognised testing organisation is required for legal fitting.

The test engineer can decide whether the tyres may be used if proof is provided by the tyre manufacturer that the tyres have been tested and approved for the vehicle in question. In short: The probability of approval is low, and there are also high costs and a bureaucratic effort that is generally not worthwhile.

The right tyres with the EC certificate of conformity

The EC certificate of conformity helps to find the right wheel/tyre combination for the vehicle. In case of doubt, the garage or dealer can also help to determine the correct tyre size. However, drivers should never drive on tyres that are not approved for their vehicle.

Not only do they risk a heavy fine, but road safety can also be severely impaired and, in the event of damage, the insurance company may refuse to cover the costs. So it’s better to do without the sporty look and only drive with approved tyres.

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