Every tire manufacturer stamps the sidewall of their tires with a tire tread rating. This tread rating gives you, the consumer, three pieces of information. The first is an alpha character defining how your tire held up to temperature extremes under manufacturer testing. The second is also an alpha character that shows the manufacturer’s rating for the traction capabilities of your tires. The last piece of information is a number that shows how well your tire fared in manufacturer tread wear testing. With the alpha ratings, an “A” is most desirable, and with the tread wear rating, the higher the number, the better. Buyer beware: these tests are not standardized. Also to be noted, the higher the traction rating, the lower the tread wear rating is going to be. Because high traction tires are, by definition, softer tires.
For more info, see How to Check Your Tire Tread