What is my factory tire size?
The factory tire size is the original tire size specified by the manufacturer for your exact model and trim. It’s typically listed on the door jamb placard and in the owner’s manual, and you can confirm it via the VIN/build sheet.
If you’ve ever wondered which tires came on your car from the factory, this guide explains where to look, how to read the code, and what to do if official placards are missing.
Where to find your factory tire size
Use official sources that identify the original equipment size for your vehicle. Depending on your situation, one or more sources may be easiest to access.
- Door jamb placard: A sticker on the driver’s door or door frame shows the original tire size, load index, and speed rating for front and rear tires (if different).
- Owner’s manual: The recommended tire sizes are listed in the maintenance or specifications section.
- Vehicle identification number (VIN) and build sheet: Manufacturers’ databases or dealership portals can provide the OE size when you look up your exact VIN; some apps and sites offer VIN-based tire size data.
- Original equipment paperwork or window sticker: If you still have the window sticker from new, it includes the OE tire size.
- Spare tire and dealer records: Some cars use different sizes for the spare; check the spare and the service records.
Cross-checking these sources helps confirm the OE size, especially if the vehicle has multiple trim levels or optional packages that could alter the standard tire size.
Understanding the tire size code
Original tire sizes are written in a compact notation on the sidewall. Knowing what each part means helps you verify compatibility and avoid replacing with an incorrect size.
- Prefix: P, LT, or T indicates the tire type (P for passenger car, LT for light truck, T for temporary spare).
- Width: The first number (in millimeters) is the tire width from sidewall to sidewall.
- Aspect ratio: The second number is the height of the sidewall as a percentage of the width.
- Construction: The letter (usually R) indicates radial construction.
- Wheel diameter: The number after the construction letter is the wheel diameter in inches.
- Load index and speed rating: The final numbers/letter indicate how much weight the tire can carry and the maximum speed it’s rated for.
Note that OE sizes can differ for front and rear wheels on some models or depend on trim level. Always verify the exact size for your specific configuration before purchasing tires.
Practical notes on interpreting the code
Examples help: a common OE size might appear as P225/60R16 97T. Decode it as a passenger-car tire, 225 mm wide, 60% aspect ratio, radial construction, fits 16-inch wheels, load index 97, speed rating T. Variations exist, so confirm the exact numbers listed on your vehicle’s placard or manual.
What to do if you can’t locate the OE size
If the door placard is missing or damaged, you still have options to confirm the OE size. The following steps help you determine the original specifications safely.
- Check the VIN build sheet or window sticker obtained from the dealer, if available.
- Look up the vehicle’s specifications by VIN on the manufacturer’s site or a trusted third-party database.
- Consult your service history or the original sales paperwork for tire information.
Always exercise caution when using aftermarket sizes. If in doubt, contact an authorized dealer or tire professional to confirm the correct OE size for your exact model and trim.
Summary
Locating your factory tire size involves consulting the door placard, owner’s manual, VIN/build sheet, and any original paperwork. Understanding the size code helps you verify compatibility and choose appropriate replacements that match the vehicle’s original specifications. When in doubt, verify with a dealer or tire professional to ensure safety and warranty alignment.
