Informed tire buyers will consider many factors when purchasing tires (see our Pre-Purchase Checklist for Tires), but at the top of many priority lists is tire durability.
And rightly so. Tires are often the most significant “repair” cost that drivers face during the duration of vehicle ownership, and everyone wants to avoid prematurely incurring the expense of new tires.
How can tire buyers be confident that they’re purchasing a tire with strong treadlife and therefore solid long-term value?
Treadlife warranty is certainly one reference point. While it’s an area of some marketing tomfoolery, generally speaking manufacturers won’t warranty a tire for 50,000 miles when they really expect it to last 25,000 miles. 500 treadwear grade on a tire sidewall Treadwear grade, aka treadwear rating, aka Uniform Tire Quality Grading (UTQG), is another reference point that hints at a tire’s longevity.
Treadwear grade is a rating mandated by the National Highway Traffic Safety Administration (DOT) that applies to all tires, with the exception snow tires. However, it’s not DOT that evaluates the tire and assigns the rating, it’s the tire manufacturer’s duty to do so.
A treadwear grade is assigned to a tire after testing by the manufacturer (or a third party testing organization) in controlled conditions. We won’t bore you with treadwear grade testing methodology (go here for full details), but suffice it to say that it’s imperfect. At the same time, meaningful data is typically yielded from the testing, and to a certain extent that data filters down to the consumer in the form of a treadwear grade.
So how do you interpret a treadwear grade? Easy peasy… sort of.
In simple terms, the higher the treadwear grade number, the greater the treadlife.
Tire “A” with a 600 treadwear grade has superior longevity as compared to tire “B” with a 300 treadwear grade. In fact, in this example, tire “A” will have about double the treadlife of tire “B” — 300 x 2 = 600.
But here’s the rub:
Each tire manufacturer utilizes their own treadwear grade scale. So while Continental tire “A” with a 600 treadwear grade should have about double the tire life of Continental tire “B” with a 300 treadwear grade, Michelin operates according to their own scale. A 300 treadwear grade Michelin tire could last much longer or shorter than Continental’s tire “B” also with a 300 treadwear rating. Drat…
Treadwear grade is therefore most informative when comparing two tires from the same manufacturer. When comparing treadwear grades of tires from two or more manufacturers (as is most common when tire shopping), the treadwear rating is less instructive.
However, comparing treadwear grade across manufacturers isn’t lacking value altogether, as our survey demonstrates.
We took a look at three popular categories of tires, and compared treadlife results (via user data) in relation to treadwear grade.
What we found almost without exception, and regardless of the brands being compared, is that tires with verifiably substantial treadlife most often have a treadlife grade that is much greater than the treadwear grade of tires with less treadlife.
For example, in the standard touring all season tire category, the Continental TrueContact is the established category frontrunner with proven treadlife, and a treadwear grade of 800.
Lesser tires in the same tire category with notably less treadlife have ratings of 500, 300, 300, and 260.
In the grand touring all season tire category, it’s the Michelin Premier A/S that has become recognized for longevity. Treadwear grade: 640. Lesser tires in the same tire category with notably less treadlife have ratings of 400 and 480.
Michelin is also known for long-term value in the highway all season category with the Michelin Defender LTX M/S. Treadwear grade: 800, with reports of 50,000-70,000 miles common.
We achieved about 30,000 miles on our set of Goodyear Fortera HL Edition tires – treadwear grade: 540. Lesser tires in the same tire category with notably less treadlife have ratings of 400, 300, and 280.
And so while a true 1:1 treadwear grade comparison across tire manufacturers isn’t possible, it is still instructive to compare tires from competing manufacturers on the basis of treadwear grade. A 600 treadwear grade Michelin tire might not last twice as long as a 300 treadwear grade tire from Manufacturer X, but generally speaking buyers can expect substantially more treadlife from the 600 treadwear grade tire.
Considered in combination with treadlife warranty and user data, drivers can make educated projections on the lifespan of tires based upon treadwear grade.
