If you've ever been confused about how to read tire information
on the sidewall of your tires your not alone. Many people are confused
by the numbers and symbols stamped on the sidewall.

Fortunately the good folks at the Department of Transportation initiated
something called the UTQG system. The Uniform Tire Quality Grading
allows consumers to compare tires in several important categories such
as temperature and treadware traction. If you still have questions concerning
the information your local tire dealer  will be happy to assist you.

It is important to know that each  manufacturer of tires establishes
the UTQG ratings for the tires they produce.

Temperature and traction ratings follow a letter pattern such as A,B or C
for temperature and  AA, A, B and C for traction. These ratings are based
upon controlled government tests.

Treadwear is rated by numbers. A tire rated 300 would last 3 times as long based on
controlled conditions at a government test facility. The key point to remember here
that this is based on controlled tests. The actual wear of the tire is dependant on
many factors such as road conditions, driver habits, service of the tires
and weather conditions. Keep this in mind when purchasing your next set of tires.

How to Read the Side of Your Tire

Author: Brock Frye

Your tire is one of the most often replaced items associated with your vehicle. It's going to be replaced eventually; and knowing what information your tire holds can be the difference between getting the correct replacement and enjoying it just as long as the previous and getting a weird European version that's rated for something completely different. Few people understand the wealth of knowledge contained in the letters and characters that occupy space along your tire wall. But they can provide valuable information that will keep you from prematurely aging your tire and encountering a roadside emergency. So, because I feel everyone can benefit and out of my own curiosity, I'm going to decipher it for you.
Well, the most obvious things that your tire indicates are the name of the tire, like the "Forest Hugger" or the "Road Melter" series. These are just to be able to easily discern the differences between tires of the same size by the same manufacturer. They don't really mean anything important. The next that you'll notice is the manufacturer's name. Hopefully, you already knew this. There are pretty huge differences between the manufacturers of tires. A few years back, Firestone made a bunch of tires that blew up randomly, so choose your manufacturer wisely.
Moving on to the actual coding, you're going to encounter first what is called the service description. These are letters that tell you what kind of vehicle the tire is rated to support. "P" stands for passenger car, "LT", light truck, "ST", special trailer, and "T" for temporary. These markers refer to the U.S. or P-metric method of tire sizing. If your tire doesn't include one of these service descriptions, it's classified as a Euro-metric tire and it conforms to the European tire specifications. It's important to get the correct service description because each leads you to a different load index, which is how much weight your tire can carry.
The first number that you encounter on your sidewall indicates the tire width. It tells you the width of the tire from sidewall to sidewall in millimeters. The larger the number is, the wider the tire.
Then you'll encounter a backslash which indicates nothing. It's there to separate the number of the tire width from the next number which tells you the aspect ratio. The aspect ratio is the height of the tire in comparison to the width. So, if you encounter a 70, your tires height is 70% of the width. Lower numbers are usually reserved for tires that improve steering response and handling.
Now you're going to see another letter immediately after the aspect ratio. This letter lets you know the internal construction of the tire. Radial tires, marked with an "R", have been the standard for passenger car tires for over 2 decades. Before that, both radial and bias-ply, "B", tires were used. But since radial took over, bis-ply are mainly only used on certain trucks.
The last number in the main sequence indicates your rim diameter. This number is given in inches and deserves a great deal of attention if you plan on upgrading your wheel size.
The next grouping consists of a number and a letter. The number tells you the tires load index. This is a measurement of how much weight each tire is designed to carry. You can look up the meaning of the number online on any of a number of Load Capacity per Tire Charts, because the number does not directly relate to an actual incremental measurement. Keep in mind that the weight listed on the chart should be multiplied by four because all four tires can support that much weight. So, if one tire can handle 1,500 pounds, then your vehicle can handle up to 6,000 pounds if the tires are properly balanced and filled, in ideal circumstances. It's not a recommendation to fill your vehicle with 6,000 pounds, but your tires could probably handle it as long as you took into account the weight of the vehicle itself. Some tires are rated "XL". This is indicates that the tire is rated for extra load. It is important to replace XL tires with XL tires. Now, it's important to get the correct load capacity chart for your tire. You can make sure of this by referring to the P-metric or Euro-metric markers on your tire. P-metric and Euro-metric sizes are mostly the same, but the load index from each tire of the same size may be different. You lose a couple of points with P-metric tires, so the rule is that you can replace a P-metric tire with a Euro-metric because you'll gain load capacity. But never replace a Euro-metric with a P-metric because your tires won't share the same load index.
Pay attention to the load index of your tires because they are the only indication of the weight your tires can carry. The size of a tire doesn't matter. The air inside is what carries the load, so larger diameter tires with smaller aspect ratios don't carry more weight.
The last letter that you encounter on the sidewall indicates the speed rating of your tire. It tells you how fast you can travel on those tires before centripetal force starts to tear it apart. The most common rating is "H" and it is rated for speeds less than 130 mph. Again, you can find a full listing of speed ratings on any number of online charts.
Speaking your tires language helps you know what your tires can and cannot do. The information held on the sidewall is essential to finding the correct replacement tire and avoiding emergency roadside assistance, if you choose to ignore the load index or speed rating.
Article Source: http://www.articlesbase.com/automotive-articles/how-to-read-the-side-of-your-tire-3651223.html

Tire pricing and tire warranties are something you should give careful consideration to and fully understand before you purchase your tires. Failure to understand what is and is not covered in the
warranty could result in confusion and misunderstanding between you and the tire dealer
who sold the tires to you. Remember to always read the fine print and keep records as well
as all receipts to back up your claim.

What is a tire warranty:
With regards to tires a warranty is simply a promise by the maker of the tire that they will stand
behind the tire and will replace or fix any problem with the tire caused due to inferior materials
or poor workmanship. Warranties will be limited, meaning they will not cover everything that
could possibly go wrong with your tires

Read on to learn more about four of the more popular warranties offered by tire manufactures and how this will affect tire pricing.

Material and Workmanship: This covers problems with the tire that were under the control of
the maker of the tire. If the materials were suspect and this caused problems with the tire the
maker of the tire will replace it usually at no cost to you. Sometimes this is prorated depending
on how much tread life is left on the tire. Conversely if the tire is defective due to workmanship
of the employees in the company the tire will usually be replaced free of charge.

Uniformity Warranty: If a newly purchased tire causes your vehicle to ride rough or contributes to other handling problems the manufacturer will usually replace the tire. Even though tires are manufactured with strict quality control standards variances do occur. Keeping this in mind if you
notice problems with your vehicle occurring after one or more new tires has been installed you should
bring it to the immediate attention of the tire dealership where you made the purchase. If you wait
to long before bringing it to the attention of the dealer the assumption might be made that other
contributing factors such as road conditions or additional problems with you vehicle might be to blame
and the manufacturer may be reluctant to honor the warranty.

Tread Life Warranties: This type of warranty offers assurance to the consumer that the tire will be
replaced if the tire wears out sooner than it should. There are certain conditions that must be met to take advantage of this type of warranty and many times it is not worth the hassle the consumer must go through to obtain the warranty. This is usually prorated based on the miles of travel. Remember to qualify for this type of warranty  your tires must wear out before the mileage guarantee offered by the manufacturer.

Road Hazard Warranties: This type of warranty is an additional type of warranty that can be purchased by the consumer to protect against hazards your tires face under normal driving conditions. Punctures to your tires caused by things such as nails, glass and damage caused by pot holes are just some of the things that a road hazard warranty may cover. On some tire make and models this type of warranty is becoming difficult to find. Remember this warranty only covers damage your tires face under normal driving conditions so keep this in mind before purchasing.

A final thought concerning tire pricing and  warranties. As already mentioned keep all receipts that come with the purchase of your tires as well as any other information given to you by your tire dealer. This will become very important if you ever need to take advantage of your warranty.