Tire buying guide

Tire buying guide

Getting ready to purchase tires for your car? Great! This tire-buying guide will give you all the information you need to purchase the right tires for your car and your lifestyle. From determining the right time to buy new tires, to making sure you pick the right size and type for your vehicle, the SimpleTire.com Buying Guide has you covered.

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When do I need to buy new tires?

Tires are more complicated than they seem but we’re here to make them simple. Most importantly, you should check your tires at least once a month to ensure your tires are safe to drive on. A flat doesn’t necessarily mean your tire needs to be replaced but you will want to get your vehicle serviced and have a trained technician assess the damage to the tire since they’ll tell you what they recommend. There are three things to consider when trying to figure out if a repair is possible;

  1. Have you driven on the tire while it’s flat?
  2. Is the damage in the sidewall (the part that doesn’t touch the road)?
  3. Is the puncture less than ¼ inch deep?
  4. Are your tires worn to 4/32 or less tread depth?

You’re more likely to need a replacement if the answer is “yes” to one or more of the above questions.

Two common ways to check tread depth (tread wear)

Penny test

Penny Test

Take a penny and put it into the most shallow tread groove with Lincoln’s head facing down. Is the top of his head visible? If so, then your tires need to be replaced.

Wear Bars

Wear Bars

Look at your tire; See those lines that go across the big grooves like in the picture above? Those are your tire’s wear bars. They’re to show you, easily, how close your tire is to 2/32 inch depth which is the legal minimum. If you can see these bars then your tire needs to be replaced as soon as possible.

How many tires do I need?

This question is a little more complicated so stick with us here. The quick answer is “as many tires as you need to replace” but it’s not that easy. Depending on the age of your tires, you might replace one and find that your vehicle pulls to one side, doesn’t stop as well as expected, or isn’t as responsive in rainy or snowy weather. That’s caused by uneven tread; Basically, your tires don’t all grip the road the same way anymore because the new tire is doing a better job than the rest.

Replacing One Tire

Find the exact match to the tire that you’re replacing. Brand, model, speed rating, and load capacity need to be an exact match or you will likely experience the above conditions; poor handling, pulling, or compromised braking. It is not recommended to replace only one tire without at least replacing the tire on the opposite side unless the tread is barely worn (less than 2/32nds used).

Replacing Two Tires

When you need to replace two tires it’s best to rotate them to the back and have the older two on the front to help prevent fishtailing. In simplest terms; Your front tires grip the road and tell your vehicle what direction to go in while your back tires grip the road to follow. If the front of your vehicle says “turn” but the back isn’t following then your vehicle will fishtail, which means the back end swings out to the side. If you’ve ever had your vehicle side on ice then you have an idea what fishtailing would feel like.

Replacing Three Tires

Please don’t replace only three tires. If you have to replace three tires then it’s best to just replace all four and avoid the complications of mismatched tread depths. If you really have to replace just three tires then make sure that two of the new tires are mounted on the back to help prevent fishtailing and reduce the risk of hydroplaning.

Replacing Four Tires

This is always, always, the recommended approach. The only reasons not to replace all four tires at once is either because your tires are already new and only one or two were damaged by a road hazard or because replacing all four is too expensive. However, for your safety (and the safety of everyone in the vehicle with you) we, and anyone else in the automotive industry, will always recommend replacing all four tires at a time. Good tires are expensive and that’s why we work with a number of companies that provide financing options, so you don’t need to compromise safety in the name of finances. Check out our Financing Options Page for more information.

How do I pick the right tire size?

The simplest way to find your tire size is by putting your vehicle make, model, year, and trim into our tire finder. We’ll search our database and find the tires that come standard on your vehicle, saving you time and effort. If you still want to physically check for yourself then there are three ways to figure out what size tires your vehicle needs; You can look at your owner’s manual, on the inside of your vehicle’s driver side door well, or read the size printed on the tires you already have mounted.

How to analyze the sidewall

This can be a bit tricky since there are a lot of letters and numbers printed on the side of your tire but, like always, we’ll make this as simple as possible.

Dangerous Tire Cracking

Tire sizes will almost always begin with a letter (the P in P205/55R16) and usually appear as the biggest numbers on the tire. In the image above you see 205/55R16 91V. Notice that there’s no P? If you don’t see the letter, don’t worry. All you need to know for now is what you’re looking at; In 205/55R16 you’re seeing the Tire Width (205), Aspect Ratio (55), Construction Type (R), Wheel Diameter (16), Load Index (91), and Speed Rating (V).

But what does the letter mean?

Very simply, “P” stands for Passenger and “LT” stands for Light Truck. Passenger and Light Truck tires are the most common tire types. Unless you’re driving a specialty vehicle you’re only going to see these two letters (or none at all).

Tire Width

The first number after the letter (if there is a letter) tells you the width of your tire, in millimeters. This is the distance from one side of the tread to the other. If you’re the curious type, take a ruler or measuring tape and lay it across the tire; you should see the same number on your measuring tape as is printed on the side of your tire.

Aspect Ratio

Simply put, this is how tall your tire is. In even simpler terms, this is how much sidewall you see when the tire is mounted. Performance tires tend to have a lower aspect ratio while your typical all-season passenger tire will be between 65 and 80.


That “R” means your tire is a Radial tire. All modern tires are radial tires, with very few legacy exceptions for classic cars or specialty vehicles (like farm equipment). Sometimes you might see “VR” or “ZR” but that just means the tire’s speed rating is V or Z, which we’ll explain more below.


This is the diameter of the empty hole in your tire where the wheel goes. In the above you see that the diameter is 16 so this tire goes on a 16 inch wheel. Diameter does not refer to the overall diameter of the tire.

Load Rating

The Load Rating tells you how much weight your tire can hold by itself when mounted and filled with air. For example, the tire above has a 91 load rating and can hold 1356 pounds by itself. Just keep in mind that your max load rating will be multiplied by all the tires on your vehicle. So 1356 pounds x 4 tires = 5424 pound max load.

Speed Rating

Every tire gets a speed rating which is then marked by a letter. The speed rating tells you the maximum speed that your tire can safely reach before it will start to breakdown or be at risk for failure. The above example has a speed rating of V which means it can travel up to 149mph safely.

What tires best match my driving conditions?

Not all tires are created equal but every tire is made with a purpose. Depending on where you live and the conditions you find yourself in you might need different tires than someone who lives and drives elsewhere. Do you live in an area where it snows frequently or have you only seen snow in movies and shows? Are you driving in the city or out on dirt roads? These are things to consider when considering the type of tires you will need. Your best bet is to consider the worst possible conditions that you’re likely to be driving in then pick a set of tires that will match that and your standard.

Worst possible driving conditions

Let's look at the extremes; If you live where it snows frequently then you might want to buy a set of winter tires. They’re designed specifically to grip in snowy, wintery conditions and they excel at it. They don’t do so well in hot climates, though, so if you’re somewhere that never gets snow and often reaches high temperatures then you wouldn’t want winter tires. Your best bet would be a set of summer tires which are designed to handle the hot asphalt without breaking down. For everyone somewhere in between there are all-season tires, which are also much more common, because they do well in either condition but don’t really stand out either.

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