About WhichTractor

What is on the site

• 2,500 tractors from 71 makes, each on its own page.
• 125,220 stored values, of which 100% carry a cited, dated source.
• 2,843 sources cited, listed on the sources and licences page.
• 177 laboratory test reports on file, covering 38 machines measured at the PTO shaft.

Everything is free to read, with no account and no sign-up, and the data is published under CC BY-SA 4.0 so you can take it away and use it. Our terms set that out.

How the data is built

These are the rules the site is built to, not aspirations:

• Every stored value carries a source. The source, the page and the date we read it are recorded with the figure. A value with no source is not written down — the database physically refuses it.
• Power standards are never mixed. Gross engine power, net engine power, PTO claimed, PTO measured, drawbar measured, OECD and ECE figures are different quantities and are stored as different things. Every figure on a page is labelled with which one it is.
• Disagreements are shown, not resolved silently. Where two sources differ, the page says so.
• A page publishes only when it is complete enough to answer a buyer. A record missing the essentials for its era is simply absent: no stub, no empty table, no "specifications coming soon". Several thousand records are held back on that test right now.
• Nothing is compiled from another compilation. We work from primary and reference sources — laboratory test reports, official registers and reference works — never from a competitor's pages.
• Nothing is guessed. Where a source does not say, the page says "unspecified". That is a value, and it is the honest one.

The full method, including how figures are verified and what the quality gate requires, is on thehow the data is checked page.

About the pictures

Photographs are licensed, usually from Wikimedia Commons, and carry their photographer and licence beneath them. Where no photograph of a model exists, some pages carry an illustration drawn from that model's own specification record — its drive, its operator station, its dimensions, its period paint. Those are captionedIllustration — not a photograph directly under the image, every time. They carry no manufacturer's emblem, wordmark or model lettering, and they are never presented as photographs of real machines.

How we collect, and how to stop us

Our fetcher identifies itself on every request, reads no more than one page every two seconds, obeys robots.txt, and stops permanently on any block — no proxy, no retry, no second route. If you run a site we read and you want us to stop, one email does it, the same day. The details are on the WhichTractorBot page.

When we are wrong

Sources contain errors and so, therefore, do we. Corrections are read by a person and acted on: send the page, the figure and, if you have one, the source. There is a form on the corrections page, or email corrections@whichtractor.com.

We are not affiliated with, endorsed by or a dealer for any manufacturer, and we do not sell machines, parts or leads. Manufacturer names appear here to identify machines.