Methodology
Where every number comes from and how it is cited.
Sources
We use documents published by the vehicle manufacturer for the U.S. market:
- Owner's manuals for oil capacity, wheel nut torque, tire sizes and, for Toyota, towing ratings.
- Towing guides and trailering charts from Ford and Chevrolet for towing ratings by configuration.
- Diesel supplements where the main manual sends you to one.
- U.S. EPA data from fueleconomy.gov for fuel economy.
Every document is listed on the sources page, and every figure on the site names the document and the page it comes from.
Page numbers
Every citation gives the page of the PDF file as published by the manufacturer. The page number printed on the paper can differ by a few pages, because covers and inserts count in the PDF.
Copied as printed
Specifications are published exactly as the manufacturer prints them: nothing is rounded, converted, averaged or estimated.
Some values are calculated from a published figure, such as a tire's overall diameter from its size, and articles use worked examples with round numbers; both are labeled as such. When several model years share the same figures, the table groups them and lists the document for each year.
Manuals sometimes contain mistakes, such as a pound figure that does not match its kilogram figure. In those cases the figure is shown as printed with a note under the table explaining the problem.
Oil capacity "with filter"
Oil capacities are the figures the manual gives for an oil and filter change. Where a manual lists the engine oil capacity without saying whether the filter is included, the figure is marked with †.
Towing ratings
Towing figures are maximum loaded trailer weights for a properly equipped vehicle, as published. They depend on cab, bed, axle ratio, packages and hitch type, so always use the row that matches your truck and check the labels on the driver's door jamb. Never exceed GVWR, GAWR or GCWR.
Corrections
If a figure is wrong, tell us with the year and configuration. We check it against the source page and record every change on the corrections log.