Know Your Numbers

Tire Size Guide — Read Your Sidewall in Seconds

That string of numbers on the side of your tire tells you everything we need to get you the right replacement. Here's how to read it — no jargon.

Buying tires gets a lot easier once you can read your own tire size. It's printed right on the sidewall and it looks something like 225/45R17 94V. Each part means something specific — and once you know what, you'll never guess again.

Where to find your tire size

You have two reliable places to look:

  • The tire sidewall. Look for a code like 225/45R17 molded into the rubber on the outer face of any tire. This is the size that's currently on the vehicle.
  • The driver's door jamb sticker. Open the driver's door and check the frame (or sometimes the fuel-door or glovebox). There's a placard listing the manufacturer's recommended tire size and the correct inflation pressures. Your owner's manual has it too.

If the tires on the car match the door sticker, you're set. If a previous owner changed sizes, it's worth a quick call so we can help you get back to a safe, correct fit.

What each part of the size means

Let's break down our example — 225/45R17 94V — one piece at a time:

CodeNameWhat it tells you
225Section widthThe width of the tire across the tread, in millimeters. Here, 225 mm.
45Aspect ratioThe sidewall height as a percentage of the width. 45 means the sidewall is 45% of 225 mm. A lower number = a shorter, sportier sidewall.
RConstruction"R" is for radial — the standard construction on virtually all modern passenger tires.
17Wheel diameterThe wheel (rim) diameter the tire fits, in inches. This one fits a 17-inch wheel.
94Load indexA code for how much weight the tire can safely carry. 94 equals roughly 1,477 lbs per tire. Always match or exceed your placard.
VSpeed ratingThe maximum rated speed for the tire. "V" is rated to 149 mph — again, match or exceed what your vehicle calls for.

So 225/45R17 94V reads as: a 225 mm wide radial tire, with a sidewall 45% of that width, built for a 17-inch wheel, rated to carry about 1,477 lbs and safe up to 149 mph. Want a deeper walkthrough with more examples? Read our blog post on how to read a tire size.

Common vehicle size examples

Sizes vary by trim and wheel package, so always confirm against your own sidewall or door sticker — but these give you a feel for the range:

Vehicle typeTypical size example
Compact car (e.g. Honda Civic)215/55R16
Midsize sedan (e.g. Toyota Camry)225/45R17 or 235/45R18
Small SUV / crossover (e.g. RAV4)225/65R17 or 235/55R19
Full-size pickup (e.g. F-150)265/70R17 or 275/55R20

How to know when it's time to replace

Even the right size won't help if the tire is worn out. Replace tires when you notice any of these:

  • Low tread. Try the penny test — insert a penny into the tread with Lincoln's head pointing down. If you can see the top of his head, your tread is at or below 2/32" and it's time.
  • Tread wear bars showing. Those small raised bars running across the grooves are level with the tread when the tire is worn out.
  • Cracks, bulges or blisters in the sidewall — signs of age or internal damage that a repair can't fix.
  • Repeated flats, vibration, or pulling that doesn't go away after balancing and alignment.
  • Age. Many tires should be replaced around 6 years regardless of tread, and no later than 10 — the rubber hardens over time.

Can't find your size — or not sure what it means? Snap a photo of your sidewall and text or call us, or just read us the numbers over the phone. We'll identify the right tire for your vehicle and give you an upfront price. Call (682) 392-2068 — we're open 24/7 and we come to you.

When you're ready, we can bring the tire to you and install it on the spot. Learn more about our new tires and tire replacement service — no shop visit, no waiting room.

Questions

Tire Size FAQ

Have another question? Call us any time at (682) 392-2068 — we're open 24/7.

How do I read my tire size?+

Your tire size is the string of numbers and letters on the sidewall, like P215/65R15. Read it left to right: the three-digit number is the width in millimeters, the two-digit number after the slash is the aspect ratio, and the number after the R is the wheel diameter in inches. If it looks confusing, snap a photo and we'll read it for you.

Where is my tire size printed?+

The most reliable place is molded right into the tire's sidewall. You can also find the manufacturer's recommended size on a sticker inside the driver's door jamb, and it's usually listed in your owner's manual too. Any of those spots will give you the numbers we need.

What do the numbers in a tire size mean?+

Take 215/65R15 as an example: 215 is the tread width in millimeters, 65 is the aspect ratio (the sidewall height as a percentage of the width), R means radial construction, and 15 is the diameter of the wheel in inches. Together they describe exactly what tire fits your vehicle.

What are the load index and speed rating?+

After the main size you'll often see something like 95H. The number is the load index, which tells you how much weight the tire can safely carry, and the letter is the speed rating, which is the maximum safe speed. It's important to match or exceed your vehicle's original ratings for safety.

Can I put a different size tire on my vehicle?+

Sometimes, but it's not something to guess at. Changing size can affect your speedometer, handling, clearance, and safety systems, so it's best to stick with the manufacturer's recommended size unless a professional confirms an alternative is safe. Call us and we'll help you find the right fit.

Do I need to know my tire size when I call?+

It's helpful but not required. If you have it, great — it speeds things up. If you don't, no problem: give us your vehicle's year, make, and model when you call (682) 392-2068 and we'll figure out the correct size for you.

How do I check how old my tires are?+

Look for the DOT code on the sidewall; the last four digits are the manufacture date. For example, 2521 means the 25th week of 2021. Tires generally should be replaced around six years old regardless of tread, so if yours are getting up there, it's worth having them checked.

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Read us your sidewall or send a photo. We'll match it, quote it upfront, and install it right at your location — day or night.

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