How Useful is the Treadwear Grade?

When looking at new tires, you'll notice a stamp on the tire that gives a "treadwear" grade. This grade will read 150, 300, 500 or higher. The numbers are simple to read--if a 300 grade tire wears at at 100,000 miles, a 500 grade tire should wear out at a higher mileage. When you go to buy tires, don't forget that these ratings are only accurate on tires of the same brand. The reason? A tire graded at 500 made by Company X has different testing standards than Company Y. A "500" from Company X may mean something quite different on Company Y's testing ground. If you buy tires from the same manufacturer every time, the treadwear grade isn't much of a mystery. If you are finding tires from a different manufacturer, do some research and get the skinny on how those tires perform at the different ratings. You can use that as your baseline when trying to figure out what grade tires your vehicle needs.