Call any tire shop for a price and the first question is the same: what size? It is not small talk. Tire prices and availability are figured by exact size, and two vehicles that look identical can take different ones. The good news is that the size is printed right on the tire, it takes about thirty seconds to read, and once you know what the numbers mean, you will never be stuck on that question again.
Where to find it
The size is molded into the sidewall of every tire — a string of numbers and letters like 225/65R17. The size your vehicle left the factory with is also on the driver's door placard and in the owner's manual. If the tires on the vehicle now are not the factory size, the placard and the manual are the record to trust.
What the numbers mean, using 225/65R17
- 225 — the width of the tire in millimeters, sidewall to sidewall.
- 65 — the aspect ratio: the sidewall's height as a percentage of the width. A bigger number means a taller sidewall.
- R — radial construction, which is effectively every passenger tire on the road today.
- 17 — the wheel diameter in inches. This is the number that cannot be fudged: a 17-inch tire only fits a 17-inch wheel.
- The letters in front — a P means a passenger-vehicle tire; LT means light truck, built for heavier loads. Many truck sizes have no letter at all.
- The numbers after — a load index and speed rating, like 102H, describe how much weight the tire is rated to carry and the speed it is built for. They matter most on trucks that tow or haul.
Why year, make, and model alone are not always enough
Trim levels change wheels. The same model of truck or SUV can leave the factory on two or three different wheel sizes depending on the trim and options, which means the honest answer to "what fits my vehicle" sometimes starts with "which version of it." The sidewall never guesses — what is on the vehicle is the ground truth. If you are partway through the call, year, make, model, and the size off the sidewall are everything a shop needs to price real options.
Why it matters for your quote
With the exact size, we can check what is available, line up choices in it, and give you an installed figure — the number that actually matters. We sell more tire brands than can be listed, and most of what you find online, we can usually get for a better price, installed. The same goes for used tires: our used stock changes constantly and no size is guaranteed, but call with the size and we can check the rack before you make a trip.
Southern KY Tire Pros, 1004 Happy Valley Rd, Glasgow, KY — family-owned since 2022, open Monday–Friday, 8:00 AM–5:00 PM. Call (270) 861-2003 or text (270) 320-7359 with your year, make, model, and tire size, and we will line up options that fit. New tires are covered on our Shop Tires page, and used options on the Used Tires page.