* Check the sidewall of the tire: The tire size is written on the sidewall. This will typically look something like "225/55R17". The "17" in this example is the rim diameter in inches.
* Look at the rim itself: The rim diameter is often cast into the metal of the rim itself, usually on one of the spokes. It might be less visible depending on the design of the wheel.
* Check your vehicle's documentation: Your owner's manual or registration paperwork may specify the original rim size. Keep in mind that aftermarket rims may have been installed.
* Look up your car's specifications online: Websites like Edmunds, Kelley Blue Book, or your car manufacturer's website will often list the factory rim size for your specific year, make, and model.
* Use a measuring tape (least reliable): You can measure the diameter of the rim directly, but this is the least accurate method and requires careful measurement.
The most reliable methods are checking the tire sidewall and looking up your car's specifications online. The tire sidewall is the easiest, but remember that aftermarket wheels may be fitted, in which case the tire size and rim size may not match the factory specifications.
