How do I check whether my supplier's data is correct?

What you must do concretely

What is expected of you

The ESPR regulates in two places something that directly affects the question of whether supplier data is correct: Article 39 concerns the methods by which data are tested, measured and calculated, and Article 40 concerns the prevention of circumvention and deterioration of performance. For an importer or distributor that compiles the passport on the basis of what the manufacturer supplies, this means two different things.

Data have been created via a documented method

Article 39 of the ESPR requires that test, measurement and calculation methods are reliable, accurate and reproducible. This is first and foremost an obligation for the manufacturer or importer that supplies the data, but whoever incorporates that data into a passport certainly has something to gain from it: it provides a basis for asking how a value was established. For a company with 10 to 100 employees, this practically means that there is someone who can, if in doubt, inquire according to which method a test report was drawn up, and that asking that question is not unreasonable — it is precisely what Article 39 is concerned with. Which data specifically and how you request them is described on the page on which data you must request from your tire supplier.

Performance must not deteriorate or be circumvented

Article 40 of the ESPR is aimed at preventing products from performing differently under test conditions than in normal use, and at preventing performance from deteriorating over time in a way that is not reflected in the data. For fleet management and distribution this is relevant because the passport is a snapshot: the values in it are supposed to apply to the product as it is actually used, not only under test conditions. Practically, this means that a company that forwards data into a passport does not provide substantive assurance about how a tire will perform after years of use, but does pass on the data as supplied, without modifying or "improving" it.

Distinction between supplying and checking

What is nowhere stated in Article 39 or 40 is an obligation for the party that has the passport compiled to itself repeat laboratory tests or to check the manufacturer's measurement method. The obligation to use reliable methods lies with those who produce the data. For an importer who sources tires from outside the EU, that distinction is sometimes more nuanced, because the responsibility for the accuracy of data can then come closer — this is explained on the page on what the product passport means when importing from outside the European Union.

Where things go wrong in practice

A few situations come up repeatedly in practice among companies that pass on supplier data to a passport.

Test report and product specification do not match. A supplier sends a test report from a different year than the current production, or the report relates to a slightly different version of the tire. No one notices because the report looks "complete".

Data are copied without it being clear who established them. With tires that come in via an intermediary, it is not always clear whether the original manufacturer carried out the measurements, or whether the intermediary has taken them over from an earlier link in the chain. This makes it difficult to question the right party if in doubt.

Multiple production locations create confusion between parties. When the same tire type is made in multiple factories, the underlying test reports sometimes differ just enough to raise questions about which value is representative for the passport. How this comes together in one passport is described on the page on combining data from multiple factories.

No action is taken with a supplier that does not respond. A question about the origin of a test method remains unanswered, and in the absence of a response, the original dataset is used anyway, without any record of the question and the failure to respond being documented.

There is no contractual agreement on the quality of the supplied data. Purchase contracts often regulate price, delivery time and product warranty, but not what happens if data prove to be incomplete, outdated or inconsistent. As a result, when a problem is identified, there is no basis for holding the supplier accountable.

What you can record

• An overview of which data per product type were requested and received, with date and version, so that in case of doubt it can be traced which test report belongs to which delivery. The page on which data you must request from your tire supplier provides a starting point for what belongs there.
• Correspondence in which a test method or underlying report was requested, including the response (or the failure to respond). This is particularly relevant if it later appears that a supplier did not deliver the data or delivered it too late; see the page on what you can do if your supplier does not deliver the data.
• A documented agreement in the purchase contract on the delivery and accuracy of passport data, so that responsibility for the source of data is not only agreed verbally. What that might look like is shown on the page on recording the delivery of passport data in your purchase contract.
• A note on deviating or unclear values, with the question asked to the supplier about it and the answer received, so that if a later question from an enforcing authority arises, it can be demonstrated that a discrepancy was noted and followed up.
• A file per production location when the same tyre type comes from multiple factories, so that differences between locations do not become mixed in one undifferentiated dataset.