How We Verify Vehicle Specifications
This is how we verify vehicle specifications: every value in the vehicle database is treated as a candidate until a manufacturer document backs it. A wrong bolt pattern or torque figure can put a wheel off a moving vehicle, so verification is enforced by the build, not by good intentions: a row cannot be published as verified unless it lists at least two primary sources.
Where the database stands today
These numbers are counted from the data when this page is built, so they cannot drift out of date while the page still claims them.
- 62 vehicles, 182 generations
- 34 generations verified — 19% of the database
- 644 individual source citations, visible on each vehicle page
| Document type | Citations |
|---|---|
| Owner's manuals | 463 |
| Factory spec sheets and parts catalogs | 132 |
| Manufacturer press kits | 35 |
| Body-builder guides | 12 |
| press-spec-sheet | 1 |
| oem-parts-page | 1 |
What counts as a primary source
- OEM owner's manual. The "Wheels and tires" or "Specifications" chapter gives lug torque, OEM tire sizes and often thread pitch. Every US manufacturer publishes these as free PDFs.
- Door-jamb tire and loading placard. Mandatory on every US vehicle; gives OEM tire sizes and pressures.
- OEM service or spec sheet, body-builder guide, press kit, or parts catalog. These are where a numeric bolt circle, center bore, wheel size and offset actually appear, when they appear at all.
Not acceptable as a source: forums, Reddit, another fitment site's database, retailer product pages. Those are leads to chase, and chasing them to the manufacturer document is the work.
What "verified" certifies — and what it does not
Bolt pattern and lug torque are the two fields that decide whether the wheel bolts on and whether the nut is tight enough. On a verified row, each is backed by a genuine manufacturer document.
Center bore and thread pitch are a different story, and pretending otherwise would be the dishonest part. In practice these are almost never printed in any consumer-facing document, for any manufacturer. They live behind paid dealer service and parts systems. On a verified row, treat them as well-corroborated candidates unless that row's notes say otherwise — a few genuinely are manufacturer-sourced, and those say so.
Rules that exist because the data broke them
Each of these started as a wrong assumption caught during research, not as a principle thought up in advance.
- One generation does not mean one spec. When a manufacturer changed a stud or a torque figure mid-run, the generation is split into separate year rows rather than averaged into a number that is wrong for everybody.
- Steel and aluminum wheels can take different torque. Where the manual gives two figures, the site carries both and names which wheel gets which. 7 generations in the database do this.
- Trims within one generation can use entirely different hardware — different lug counts, different studs. Those get their own rows with the trim named.
- Some cars use wheel bolts, not studs and nuts. 7 rows are tagged for it, because thread engagement length, not just thread form, is safety-critical when fitting aftermarket wheels.
The research findings behind these rules →
How to check any of this yourself
Every vehicle page carries a per-generation sources block: the document, a link to it where the manufacturer hosts one publicly, and the full reference. Nothing on this site asks to be taken on trust — if a citation does not say what this site says it says, that is a bug worth reporting to info@checkfitment.com.
How we verify — frequently asked
What does "verified" mean on this site?
It means the bolt pattern and the lug torque for that generation are each backed by at least one genuine manufacturer-authored document, and the row carries at least two primary sources in total. The build refuses to publish a verified row with fewer than two sources. 34 of 182 generations currently meet that bar.
Why are some specifications marked unverified?
Because no manufacturer document stating that number has been found yet. The most common case is a bolt circle: manufacturers very often publish the lug count ("six lug nuts") without ever printing the 139.7 mm figure anywhere a customer can read it. Rather than present a well-corroborated guess as fact, the row stays unverified and says why in its notes.
Are center bore and thread pitch verified too?
Usually not, and the site says so. Across the dataset these two fields are almost never published in any consumer-facing manufacturer document, for any make — they live in paid dealer service and parts systems. Treat a verified row's center bore and thread pitch as well-corroborated candidates unless that row's notes state otherwise.
Do you copy data from other fitment sites?
No. Individual facts are not copyrightable but a compiled database is protected by its owner's terms of service, and second-hand data cannot be verified. Everything here is gathered from primary manufacturer sources. Retailer fitment guides are used to cross-check, never as one of the two sources.