by Richard Serra

Created on: January 01, 2010

Most of us who own a car probably never wondered or care to know what all the numbers mean that you find on a tire. We would just go to our favorite shop to have them replaced, and all the guesswork was handled by those who sell and install the tires. I had a little knowledge of what the numbers represented as far as size, but the rest was just numbers.

Little did I know that they do tell you a lot about the tire your are using, and one very important number would be the date that the tire was manufactured. This was a very little known fact that tires did indeed have a shelf life, or expectancy without ever hitting the road. Since there have been a number of fatalities due to tire failure, it was found that the tires that caused the accidents were several years old, even though they were sold as new.

Who would ever think that a new tire, even though kept in wraps for a number of years would be unsafe? I had to wonder sometimes why a shop would have a blow out sale. Now there's a play on words. Blow out was exactly what happened with a number of these new old tires. The seller of these tires knew exactly what you were buying when they sold them, but I don't think even they themselves knew that they could be unsafe.

To them, it was a matter of clearing out old inventory. To the buyer, it meant a good deal. To the unfortunate buyers, sometimes it cost them their lives. Now that the public is aware of the potential danger buying tires that are suppose to be new, but are several years old, we can see for ourselves the actual day of manufacture that these tires were made.

Along with all the other numbers, you will find four numbers, usually on the side that isn't showing. They represent the date of manufacture. They read something like 2507, which means they were made the 25th week of 2007. For the other numbers, you have width, height, an aspect ratio, a letter or two having different meanings, and it is these numbers and letters that tell provide the information you need to know for replacement.

 Three numbers represent the tire width. Example 245 =width. The next would be a two number, example, 75 equals what is called the "aspect Ratio" which is a percentage of the tires width, so a wider tire would mean a smaller aspect ratio relative to its height. The "P" means the tire is for passenger cars, and small truck tires would have an "LT"

Also the tire may show an "AA" or "A" or B & C. The AA being the best, simply means the tires traction and it's ability to stop on slippery surfaces. You may also see a temperature rating A, B, or C, and this means how well the tire dissipates heat, the "A" being the best in doing so.

Fortified with this knowledge, you should be able to make a safe choice for your tire replacements, as you can readily see for yourself what each of the tire numbers represent.

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