JacksonvilleTires.comWhen you need to buy a tire online you need to learn how to read the sidewall of your tires. The sidewall has special letters and codes imprinted on the side so you can duplicate the same tires when you buy online. Jacksonvilletires.Com, Jacksonville, Florida can help you decipher the sidewall codes and get you back on the road.
Let's take a look at a sample tire name and then we can learn how to read the same information from your actual tire.

Tire Width
Tire Width is shown as a three digit number that indicates the overall width of the tire. This number reflects a measurement in millimeters. In general, the wider your tire the better traction on the road for corners and turning.
Radial

When a letter "R" is indicated on the sideall, it means that the tire is a radial tire. This means that the tire has strips of material called carcass plies that run across the tire from side to side (or lips). These radial carcass plies provide strength to the tire so when load is applied, the load does not cause the center ribs of the tire to buckle up, thereby decreasing traction. By keeping the full surface of the tire flat on the road, more traction is applied and tire will be more flexible and comfortable to drive.
Aspect Ratio
This is a mathematical measurement that shows what percentage the height is of the tire width.
Wheel Diameter
When mounting the tire on a wheel, this indicator shows what diameter wheel will support this tire.
Load Index
When you have load applications for your vehicle (towing, heavy cargo, etc), you need to consider the load index of your tires. This measurement shows how much weight a tire can bear at maximum inflation pressure. Your vehicle comes with an OEM or original manufacturer load index for your original tires. Never purchase tires with a lower load index. To determine higher load index requirements, consult the below chart.
| Load Index |
Max Load (lbs) |
| 74 |
827 |
| 75 |
853 |
| 76 |
882 |
| 77 |
908 |
| 78 |
937 |
| 79 |
963 |
| 80 |
992 |
| 81 |
1019 |
| 82 |
1047 |
| 83 |
1074 |
| 84 |
1102 |
| 85 |
1135 |
| 86 |
1168 |
| 87 |
1201 |
| 88 |
1235 |
| 89 |
1279 |
| 90 |
1323 |
| 91 |
1356 |
Speed Rating
Your tire also has a top speed that is recommended for it. This is called the speed rating. Speed ratings are indicated by letters and is somewhat nontraditional.... it's not quite alphabetical since "H" falls between "U" and "V". Never use a tire with a lower speed rating than your original OEM tires.
| Speed Destination |
Maximum Speed Rating* |
| N |
87 mph |
| P |
93 mph |
| Q |
99 mph |
| R |
106 mph |
| S |
112 mph |
| T |
118 mph |
| U |
124 mph |
| H |
130 mph |
| V |
149 mph |
| W |
168 mph |
| Y |
186 mph |
| Z |
149+ mph |
* Exceeding the safe, legal speed limit is neither recommended nor endorsed
Mud & Snow
"M" and "S" mean that the tire is suitable for Mud or Snow applications. The Rubber Manufacturers Association evaluates these tires and certifies them for these unique uses. These letters can be represented in different ways including "M+S", "M/S" and "M&S". This mark is also shown for tires that are considered "all season tires". Jacksonvilletires.Com, Jacksonville, Florida has a complete assortment of mud and show tires so check our website.
Severe Snow Symbol
For severe snow applications some tires will bear the severe snow marking.
Treadwear
Wear by government standards is measured at 100. When your tire is rated as a 200, the expectation is that it will last twice as long. Similarly if your tire is measured as a 50 treadwear, it should last half as long. Obviously a higher treadwear rating means you will get more value from your tire.
Traction
Tires are tested for braking on wet concrete and wet asphalt. If a tire brakes well on both surfaces, it receives an A rating. If it brakes well on one surface, it receives a B; and if it brakes poorly on both surfaces, it gets a C. AA is the highest attainable grade.
Temperature
Heavy loads, under-inflation, and high speeds can raise the temperature of a tire dramatically. An A rating means the tire resists heat damage well, B is not as good, and C means the tire passes the minimum safety standards.
Helpful Tips
- Never choose a tire that is smaller than the tire that came with the car.
- If you are interested in a size other than your vehicle’s original equipment, or are upgrading, consult your local tire retailer.
To find a trusted tire installer, please visit the Jacksonvilletires.Com, Jacksonville, Florida US website.
How to Read a Tire Sidewall
by Jared Nielsen
Jacksonvilletires.Com