Iris Sefar

You might find the word TREADWEAR" on the sidewall followed by a number like 120 or 180. This is a rating of the tread's durability, as tested against an industry standard. The reference number is 100, so a tire with a treadwear rating of 200 has a predicted tread life that's twice as long as the industry standard, while a ratine of dU means a predicted tread lite thats onlu ol percentas long as the industru standaro.

The temperature rating refers to the ability of the tire to withstand heat at high speeds. The ratings, from best to worst, are: A, B and C.

A traction rating can also be found on the sidewall of all modern tires. It can be represented as AA, A, B or C. This is a rating of a tire's traction when tested for straight-line braking on a wet surface. For this rating, AA signifies the best traction performance and C indicates the worst.

Load index is a shorthand way of describing the total weight that the tire can handle when it is fully inflated. The higher the load index rating, the more weight the tire can carry. You need a tire load index rating chart to see how your load index rating correlates to the weight the tire can carry. For example, a load index of 81 means that the tire can carry up to 1,019 pounds. Load index ratings for the average vehicle range from 75-100, but some tires can range all the way up to 150, which equates to 7,385 pounds. Ask us a question below for more information.

The speed rating is a measurement of the speed at which the tire is designed to run for extended periods. An "H" speed rating signifies that this tire can be run safely at speeds of up to 130 mph for extended periods. Will it explode if it goes to 140? Not immediately. But it might, if it is run at that speed for an extended time.

Here is a complete list of the various tire speed ratings, and their associated letters:
S = 112 mph
T = 118 mph
U = 124 mph
H = 130 mph
V = 149 mph
*Z = Over 149 mph
*W = 168 mph
*Y = 186 mph
*(Y) = Over 186 mph

*The "Z" rating used to be the highest rating for tires having a maximum speed capability greater than 149 mph. But as tire technology improved, it ultimately split into the "W" and "Y" ratings. A "ZR" may sometimes appear in the size designation, as a sort of nod to the prior rating, but it will also be used in conjunction with a W or a Y. When a Y rating is enclosed in parentheses, it means that the tire is capable of speeds in excess of 186 mph.

This number refers to the maximum amount of air you can put in a tire before you harm it. It is not the recommended tire pressure; that number can be found in your owner's manual and on the doorjamb.

OWL = Outlined White Letters
RWL = Raised White Letters
ORWL = Outlined Raised White Letters
B, BLK, BW, BSW = Blackwall or Black Sidewall
W, WW, WSE = Whitewall or White Sidewall

Tread depth is a vertical measurement between the top of the tread rubber to the bottom of the tire's deepest grooves. In the United States, tread depth is measured in 32nds of an inch