A tire treadwear rating refers to the amount of time the treads on a tire should last in specific conditions. Tire manufacturers indicate treadwear rating on their tires using a set of numbers between 100 and 700. These numbers indicate how long tire treads will remain safe and perform at their highest capacity.
The treadwear rating scale starts with the number 100. Tires with this rating might be suitable for light driving or seasonal driving, as they wear more quickly than tires with higher ratings. The scale increases by increments of 50, and each increase indicates a longer lifespan. Tires with a rating of 150, for instance, should have lifespans 1.5 times that of tire with a rating of 100. Similarly, tires with a 200 rating should last twice as long.
Treadwear ratings, like other tire ratings, make assumptions to determine tread life. They assume the driver, weather conditions, and travel habits remain the same. Deviating from specific driving habits may reduce the tread life of tires. People who drive on dry, paved surfaces with snow tires, for instance, might see their treads wear out quickly. These tires are designed for traveling on snow and ice, and therefore lose tread on different surfaces. Of all the types of tires, all-season tires generally have the highest treadwear rating, while summer tires have the lowest.