What it Does
Treadwear ratings inform anticipated lifespan of a tire per…treadwear! 🙂 In other words, how long can a tire be expected to last – until it is worn to its legal treadwear limit?
Why This Matters
Value. The longer tires last, the better off you are. You get value for your money. Now, this does come with caveats: Tire quality is connected to tread life, but tire traction and grip matters too. The best tires are high value compromises that deliver on tread life, grip, strength, and temperature resistance. To make the point bluntly? Who wants a tire that will last 150,000 miles, if the rubber compound is so hard and wear-resistant that the vehicle is undrivable in the rain? Or the tires make so much noise that you “can’t hear yourself think?”
So: treadwear ratings matter in terms of tire value, and they are part of a value package (and compromises made in construction) that delivers tires that can both perform and be sold at realistic price points.
Possible Problems and Concerns
Lack of Clarity
What does a treadwear rating actually mean? They can run as low as 260 and as high as 860! Tire Rack says the following:
“UTQG Treadwear grades are based on actual road use where the test tire is run in a convoy on a 400-mile test loop in Texas (West Texas, actually) for a total of 7,200 miles. The test vehicle can have its alignment set, air pressure checked, and tires rotated every 800 miles. At the end of the 7,200 mile test, the wear on the tires is measured and compared to a reference tire that was being run under the same conditions. If the test tire is expected to last as long as the reference tire, it receives a UTQG Treadwear grade of 100. If it is expected to last twice as long, it would receive a grade of 200. 300 means it is expected to last three times as long, and so on.
The reason the Treadwear grade may not be incredibly reliable is twofold. First, since the tires are only run for 7,200 miles, the tire manufacturers have to extrapolate the remainder of the data, and that can be open to some interpretation. Second, the tire manufacturers are allowed to under-report the Treadwear grade, just not over-report it. So if a tire technically may be able to achieve a 700 rating, the manufacturer (primarily the marketing department) might want to report it as 400 to make it “”fit”” better in a certain market segment. As a result, it is generally only somewhat helpful to compare Treadwear grades on tires from the same manufacturer, and we don’t recommend comparing grades between different brands.”
*Source: https://www.tirerack.com/upgrade-garage/what-are-the-uniform-tire-quality-grade-utqg-standards (as of 2.21.23)
Unmet Expectations
You may notice a correlation between treadwear ratings and mileage warranties. But how accurate are these warranties?
Tire warranty mileage figures (50, 60k, 75k, 90k etc.) can be quite optimistic. Please: take them with not one, not two, but more like three grains of salt. Alignment condition, frequency of rotations, road surfaces, driving conditions, and driving habits all play into tire lifespan. You may want to think of such figures as the best the tire might be able to do under the most ideal of circumstances. And that’s if you even drive the car enough to hit that number of miles in six years or so. (Dry-rot and loss of rubber traction is of increased concern by that point.)
Referring back to TireRack again: https://www.tirerack.com/upgrade-garage/how-do-tire-treadwear-mileage-warranties-work
Tire Rack makes an important point: If these mileage figures are calculated for the tire being worn to 2/32,” that takes you far past 4 to 5/32″ of tread depth. These numbers are comfortably above the minimum legal tread standard, but they also represent tires that are substantially worn: worn to the point that wet traction is reduced along with hydroplaning resistance. You don’t want to buy tires assuming they’ll last you 60k miles only to be disappointed if you wind up replacing them at 45k because they’ve become a little slipper in wet conditions. But if you know what to expect, you’re better off!
Now back to treadwear ratings: Again, there’s the concept of running tires to the wear bars, and there’s the concept of running them until well-worn but not worn to the legal limit. Higher treadwear ratings can offer a better shot at reasonable (or even desirable) tire service life: even if tire replacement occurs at the well-worn point, rather than the full worn/legal limit point. But as described above, treadwear ratings also have to be taken with (at least) one grain of salt. Maybe two or three…