Tire Sizes Explained in Plain English

How to Find & Read Your Tire Size

Finding your tire size is not difficult, you just need to know where to look! In today’s article I’ll explain tire sizes, how to find yours, what the numbers on a tire mean, and how to shop for and buy tires that will fit your car or truck.

Let’s start with the basics.

How to Find Your Tire Size by Looking at Your Current Tires

When it’s time to replace your tires you could go to your local tire center and have them look it up for you. You could also look it up yourself.

But the easiest way is to simply look at the current tires on your vehicle. The numbers and letters on the sidewall of your tire will tell you exactly what size it is, and guide you toward buying the right replacement tires. Let’s take a look at what these numbers mean:

Tire Size Guide

The numbers you want to pay attention to when finding your tire size are the 

  • width, 
  • aspect ration, and 
  • the construction type / rim diameter. 

You should be aware of the load index number as well, as you’ll need tires that can support your vehicle.

Finding Your Tire Size (and how to search for replacement tires)

After you look at the sidewall of your current tires to find your size, you’ll want to remember a few of those numbers so you can search online for replacement tires. But what should you write down, and what will you want to search for?

Finding Your Tire SizeLet’s say that your tires resemble the one pictured here.

Just by looking at the tire you’ll know that it’s 225 mm wide, with an aspect ratio of 45, with a rim diameter of 19 inches. It also has a load index of 92.

To shop for a replacement you can just search online for 225/45 R19 tires and look for tires with a load index of 92 or more. This gives you the option to compare prices and reviews for yourself, and not just trust your local tire pro to order whatever pops up as the highest priced option for your vehicle, or to sell you tires that wear out quickly to ensure you’ll be back to buy more tires as soon as possible.

More expensive tires may last longer, or they may provide improved traction in inclement weather, so those may be worth paying extra for. Tires from a brand you recognize may also be better (though not always).  When it comes to buying tires, I’m all about being empowered to make a good choice, and the best way to do that is to learn as much as you can and to do some research before you buy.

Where to Buy New Tires After You Find Your Size

Now that I’ve explained tire sizes and how to find them, where should you buy your new tires? Well, you have a couple of great options.

Amazon has become one of my favorite places to shop for tires, and if I was shopping for replacement tires like the 225/45 R19 model pictured above, this is how I’d search on Amazon, and what I’d find there.

Often you’ll get a better price by buying tires directly online, and you can simply pay a local service shop to mount and balance your new tires for you, disposing of the old ones if they don’t have much life left in them. 

How to Buy the Right Size Tires (and where to buy them)

But Amazon, like some other online tire retailers, also has a relationship with some local service companies. So now when you buy tires online you can select a service center from the list, ship directly to that tire installation garage, and pay for the mounting service at checkout, right on Amazon, if you wish. And if you’re still not 100% confident in your tire size, you can use their tool to enter your vehicle make/model/year and they’ll search tires that will fit your vehicle for you.

Of course Amazon isn’t the only place you can search. TireRack.com is another good option, and offers similar options for direct-shipping to a local garage or tire shop.

If you have a tire shop you like, you can also call them up after doing the search, tell them what tires you want, and get them to quote you a price. It might be comparable to what you find online, and they might have a special promotion running (buy 3, get the 4th tire free) that you can take advantage of. They also may have dealer rates and could be able to get you the same tires for less money. Having a price from an online retailer on hand when you make that call will usually help you score a better deal.

Like any consumer purchase, spending some time doing your homework ahead of time (and comparison shopping) will get you the best deal.

Tire Size Chart

If you know your wheel or rim diameter and would like to search for different tire sizes that will fit your vehicle you can use the chart below. 

Click the tab that matches your rim size (that’s the number after “R” on most tires … i.e. R17 tires are tires for 17″ rims), and you’ll see different tire diameter options that will typically fit your vehicle. If you plan to go up a size for larger tires for your wheels/rims, you may want to speak with an expert technician at your local tire center to confirm they will fit your vehicle and perform well for you before ordering.

Please Note – I’ve included most of the more common (metric) tire sizes in this chart, but some of the very largest and oversized tires have been left off.

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