Stephan Schulze and Heiko Foltys responsible for BMF business
10. November 2022BMF sponsors Bobby Cars for kindergarten
4. July 2023
Minimum inch sizes: Explanations and adjustments
(Vehicle) data deliveries
We continue to receive data deliveries from national registration authorities - for example, the German Federal Motor Transport Authority (KBA). In recent weeks, intensive communication has taken place with test institutes and registration authorities, in the course of which the following information has become increasingly clear and uniform across the board:
The formerly technically oriented data segments (e.g. for series sizes) of the vehicle manufacturers got meanwhile replaced by a very marketing-oriented approach, so that in some cases technically mountable series sizes, which are not intended from a marketing point of view, are not (or no longer) reported for certain vehicle variants.
Research and completion of provided series sizes
We have made two changes in the internal processing procedures:
- When processing certificates, an active check is now made as to whether the inch size of the wheel potentially conflicts with the minimum inch specifications from the COC data segment. If so, a manual process is triggered to research any additional, unreported series sizes.
- The same process is also triggered when we detect the occurrence of such a case in a support ticket.
Of course, the research of this information is carried out with the greatest possible care with the aim of avoiding wrong / too small series sizes in the display. In case of doubt, this means a rather conservative interpretation of the data if they cannot be determined beyond doubt.
Example: The vehicle "Ford Mustang Mach-E GT" is reported by the Kraftfahrtbundesamt exclusively with a standard size of 20 inch, while other, national registration services also report 19 inch standard sizes. In this case, the data was completed so that the minimum inch check performed in the applications now also includes 19 inch wheels.
Selection / variants for minimum inch evaluation
After intensive discussions, we have decided to adjust the variants from the email on March 8 and will now implement the following three variants - from which you can freely choose as an application owner or data export customer.
Example COC data segment (= Opel Corsa (U) 1.2 2019-, data status April 27 2023)
The following is an exemplary list of the series sizes reported by various registration services:
German Registration number 1889 / ABT00001
- 185/65 R15 81T
- 195/55 R16 81H
- 205/45 R17 81H
German Registration number 1889/ABT00028
- 185/65 R15 81T
- 195/55 R16 81H
- 205/45 R17 81H
- 185/65 R15 81H
German Registration number 1889/ABT00144
- 195/55 R16 81H
- 205/45 R17 81H
Smallest common wheel diameter: 16 inch
Current situation
- When searching via the (complete) registration number, the correct minimum inch size is already used for the check (block 1 = 15 inch, block 2 = 15 inch, block 3 = 16 inch).
- When searching via the guided vehicle selection, the smallest common (!) inch size within the selected KWGroup is assumed as the minimum inch; in the above example this is 16 inch<, as no smaller size is available in block 3.
- Important note: These are COC data segments provided by the registration authorities. They do not necessarily have to show the smallest size that can be mounted. It is quite possible that 15 inch wheels could also be fitted to vehicles from block 3.
Variant 1
- Search for complete registration number: Unchanged interpretation; the value from the respective vehicle block / COC data segment is used.
- Guided vehicle selection: Unchanged interpretation; this means: no change compared to the current situation; in the above example, only wheels with a diameter of at least 16 inches would continue to be displayed.
Variant 2
- Search for complete registration number: Unchanged interpretation; the value from the respective vehicle block / COC data segment is used.
- Guided vehicle selection: Filtering according to the smallest (not necessarily common) value within the selected KWGroup; in the above case, this would mean that all wheels with a diameter of at least 15 inches are displayed. The user is informed of this fact with a warning indicator if the inch size of the selected wheel is smaller than the smallest common inch size of the KWGroup.
Variant 3
- Search via complete registration number: No check for minimum inch; all combinations resulting from the certificates are displayed. The user is informed of this circumstance with a warning indicator if the inch size of the selected wheel is smaller than the smallest inch size from the vehicle block / COC data extract.
- Guided vehicle selection: No check for minimum inch; all combinations resulting from the certificates are displayed. The user is informed of this fact with a warning indicator if the inch size of the selected wheel is smaller than the smallest common inch size of the KWGroup.
Variant 1 is going to be active by default. We kindly ask for your understanding that we bear the implementation costs for data management and provision ourselves; however, any necessary adjustments of frontend applications or data exports may lead to costs.
Supplementary notes
In general, the following applies today: The data from the registration authorities do not necessarily allow complete conclusions to be drawn about possible equipment relevant to mountings (e.g. larger brake system [Brembo brake for Opel, M sports brake for BMW, AMG brake for Mercedes, ...]). Therefore, these attributes are not taken into account in the evaluation/checks. This is already the case today and remains unchanged.
For further questions please do not hesitate to contact us.