Deciphering the Tire Code

Ever read the sidewall of a tire?

Do I need a tire that is capable of running at speeds in excess of 149 mph? What do all those numbers and letters mean on the tire? Thought they just needed to be round and hold air?

Speed ratings

A speed rating is a letter, which indicates the maximum speed capability of a tire, and can be broken down into 5 categories: S through Z, with S being the lowest and Z being the highest rated. It tells nothing about the tire's construction, its handling or its wearability. It is merely a measure of the tire's integrity at high speeds. The needs of different drivers warrant different tires, and it's best to talk to the specialists in the business about your vehicles' specific needs.

Treadwear basics

Treadwear grades typically range from 60 to over 500, in twenty point increments. It's important to remember that the actual life of any tire is determined by the road surface quality, driving habits, inflation, wheel alignment and the rotation it experiences. The best way to use treadwear ratings when buying tires is to compare one rating to another. For instance, a tire with a treadwear rating/ grade of 400 might be expected to last twice as long as a tire that has a grade of 200.

Want to take its temperature? How about it's traction?

The Department of Transportation (DOT) has already done that for you. Tires are graded in 3 levels, with A being the highest and C being the lowest, (just like school). Temperature grades represent a properly maintained tire's ability to dissipate heat. Traction grades indicate the measurement of a tire's ability to stop a car in straight-ahead motion on a wet test surface pavement, again with A being the highest and C being the lowest ratings. Now go take a look at your tires' report card!

You may check: Treadwear Rating on Tire Rack - Uniform Tire Quality Grade (UTQG) Standards for tires and wheels: http://www.tirerack.com/

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