Tire Mileage Ratings and Tire Replacements

April 22nd, 2020 by

A closeup is shown of a tire on a road in front of a golden sunset.

When you’re shopping for tires for your vehicle, you’re going to see a lot of letters and numbers, all kinds of different codes to distinguish one tire from another. We’re not going to get into all of them right now, because each set really deserves its own focus; instead, we’re going to take a look at the tire mileage ratings you’ll likely find for different tires. By understanding what these things mean now, you can save yourself time later when you’re at a tire shop and ready to buy.

We promise it’s not as complicated as it might seem, and by the end of this, you’ll be an expert on how to shop tires (at least in terms of mileage rating).

Treadwear Basics

So, first off, when you’re looking at mileage ratings on tires at your local tire shop, what you’re seeing is an estimate for how long the tread on the tires will last. This is not relayed through a particular duration or mileage, such as “30,000 miles,” but as a number like “200” or “700.” Also referred to as the Uniform Tire Quality Grading or UTQG, this is part of an indication of three things on a tire, actually: the treadwear, its traction score, and the temperature rating for it. Today, however, we’re only interested in the treadwear or mileage rating.

It’s important to know that while the idea of the UTQG was established by the National Highway Transportation Safety Administration (NHTSA), it is not actually gauged or tested by them. Instead, individual tire manufacturers are tasked with handling the testing to determine how their tires will stack up. If they try to exaggerate their numbers too much, or outright lie about their results, they can face serious fines. But ultimately, tire manufacturers handle figuring out the ratings for their tires – not a government agency.

How the Rating is Determined

A stack of tires in a Cincinnati tire shop are shown with a man in the back inspecting them.

Although some specifics can change from one manufacturer to another, mileage ratings that you’ll find at a tire shop are determined in essentially the same way by each maker. This procedure goes as follows:

They measure the depth of the tire’s tread when it is brand new to get the starting point.
They then place those tires on a vehicle and set it on an established course. This is typically a 400-mile course or track that they run on for 800 miles.
Every 800 miles, they will usually stop to check the tread depth, as well as check the air pressure, set the alignment, and possibly rotate the tires too.
They then continue this process to either 6,400 miles or 7,200 miles, depending on the manufacturer. The depth is once again measured, and this information is used to calculate overall tread life and rating.

Differences by Manufacturer

Many manufacturers use this base data to extrapolate the depth after 30,000 miles of use, though much like other aspects of the testing, this can vary. These differences are actually very important for one major reason: tire mileage ratings and information in the UTQG should only be used to compare two or more tires made by the same manufacturer. You cannot necessarily look at the rating of a tire from Goodyear and the rating for a tire made by Michelin and directly compare them to each other. Since they may have used different steps and procedures during the testing, you could easily find that they do not really compare.

This is important enough that it needs repeating: only use tire mileage ratings to directly compare two tires from the same manufacturer. With that in mind, however, these ratings do provide a great means of comparing two or more tires from a single manufacturer to see how they stack up. Of course, for that to be helpful, you need to know what the ratings actually mean…

What the Rating Means

The rating on a tire is based on whatever standard the manufacturer decides to use––such as 30,000 miles. While you can find out what this means, it really isn’t that important; all that matters is that you understand the baseline for comparison. Ultimately, whatever this standard is, the manufacturer sets it as a rating of 100. So, if you see a mileage rating on a tire of “100,” then you know it is predicted to last whatever the baseline is for that manufacturer.

From there, you can compare different tires from that same maker. So if you’re looking at one set of tires at your local tire shop with a rating of “150,” and another set of tires rated at “300,” then you know the second set is expected to last twice as long as the first. Furthermore, a set of tires rated at “700” will last significantly longer than the first, and more than twice as long as that second set. All of this is relative, of course, and is only a prediction based on testing under tightly controlled circumstances.

Using the Rating in the Real World

Two gloved hands are on top of a new tire.

The point we’re making here is that you cannot use mileage ratings you find at your tire shop to tell you exactly how long you’ll be able to drive on a set of tires. Your daily routine, the weight of your vehicle, the road conditions you drive on, even the speed you tend to drive at can all impact the wear on your tires’ treads. So the actual mileage you get on a set of tires will not be particularly close to what the manufacturer saw in a controlled situation on a closed track.

That being said, you can still use this information to compare different tires from the same manufacturer. If nothing else, you know that all things behind equal, a set of tires rated at “300,” will last half as long as one rated at “600.” And if you like a particular manufacturer, you can keep track of the rating of the tires you’re using and about how many miles you get out of them before replacing them. Then you can use this as your own guide to know what to expect from another set of tires from that manufacturer. If your last set of “200” tires lasted you 20,000 miles, for example, then your next set of “400” tires from that manufacturer might last about 40,000 miles––assuming you drive in the same area, with the same vehicle, in the same way.

Checking your Tire Tread

Ultimately, there is no cheat sheet for knowing when you need to replace your tires, and you need to check your tread depth regularly to make sure they’re still safe to drive. You can use a penny or a quarter and insert it with the President upside down into your tire’s tread. If you can see the top of the President’s head, then it’s time for new tires. If you use a quarter, you’ll have a little more time to shop for new tires––with a penny, if you see the top of Lincoln’s head, then you need tires right away.

Need New Tires?

Now that you know what mileage ratings mean, you’re ready to head to our tire shop for your next set. Come visit us at McCluskey Chevy today in Cincinnati, OH, and we’ll get you back on the road in no time.

Posted in Tire Shop