How we check what we publish

The design office

The Onyx Forged design office sets the measurements: those published on our car pages, in our atlas and in our guides, and those of each order.

Our texts carry no person's name: they are signed by the brand. ONYX FORGED SAS (SIREN 105 640 593) is responsible for everything published on this website; its publication director is named in the legal notice. Who we are, in facts you can check: About us.

Before your wheels are machined

The design office starts from the car you describe when you order. It does not ask you to measure anything: if needed, after the order, a photo of the registration document or the exact version of the car.

• It checks that the chosen design and diameter fit this car: PCD, centre bore, room left for the brakes.
• It turns the wheel position you chose into an offset (ET) and a width, calculated for your car.
• If you leave the settings to it (“Let our experts handle the rest”), it chooses the width, the offset, the position and the face profile, and checks the diameter ordered.
• It sends you these measurements in writing, by email: nothing goes into manufacture before you agree to them.

Once accepted, these measurements define what is manufactured; if one of them results from an error by the design office with regard to the car you described, Onyx Forged remains responsible for it (Terms and Conditions, article 3.1).

Where our measurements come from

Publication rule: a measurement is published only when a primary source gives it (a manufacturer's document, an official record from a road authority, an original equipment (OE) parts catalogue, the maker of the OE wheel) and no other primary source contradicts it, or when two independent specialist sources agree and no primary source contradicts them. The press and forums do not count.

Our primary sources are, for example, manufacturers' owner's manuals and workshop manuals, the technical bulletins they file with the US road safety administration (NHTSA), the vehicle type records published as open data by the Swiss Federal Roads Office, and official shops for original accessories. A listing from an original parts shop counts as a primary source only if it shows the manufacturer's part number and names the car; the fitment is then described as “genuine accessory”, never “standard”.

• A blank rather than a copied value: when sources are missing or disagree, the cell stays blank (“—”).
• An offset that the manufacturer gives to one decimal place (ET 44.7) is written as it is, never rounded.
• Each value links by a number to its sources, listed under the table with their address, and each page gives the date they were last checked.

These measurements describe the car as originally supplied, to identify it and compare: they are not recommendations. We do not recommend any specific offset on our pages; the calculation for your car is done when you order.

All our measurements are brought together in the open atlas of OE wheel measurements, free to reuse (CC BY 4.0 licence), and sorted by bolt pattern in the bolt patterns by car.

How we write and review our guides

This is the method followed by our guides published since October 2026.

• A guide answers a question that drivers ask, with its sources linked.
• It states no Onyx Forged price or lead time: it links to our price and lead time pages, which calculate them from the current price list. An amount quoted from a third party (a fine, a price found elsewhere) is given with its source.
• It explains and compares; it does not tell you which offset or which size to choose.
• Before it goes online, it goes through a critical review: every fact is checked again against the source cited, every copied measurement is counted again against our fitment data, and anything that does not hold is corrected or removed.
• It carries its publication date and, if it has been revised, its update date.

Three older articles, published in French on 25 March 2026 (monoblock, two-piece or three-piece construction; tinted lacquer; matching wheels to the bodywork), did not follow it: they cite no sources and do not carry this signature.

Our calculators follow the same rule: they compare two fitments or two tyres, they recommend no measurement.

Reporting a mistake

Does a measurement, a fact or a link look wrong? Write to customer service, contact@onyxforgedwheels.com, with the page's web address and, if you have one, the source that contradicts it.

The design office checks the value again in its sources and in the one you cite, then we reply to you by email. Once the mistake is confirmed, the page is corrected; a measurement that the sources no longer allow us to establish is removed from the table rather than left wrong.

Page updated on 23 October 2026.