What Do The Numbers On Tires Mean? - Tire Sizes Explained

Have you ever wondered, "What do the numbers on tires mean?" In this post, you will find these mysterious tire sizes explained. It is quite easy to understand the series of numbers and letters on your tires once you have it broken down for you. The alphanumeric code provides you with important information about the tire's type, size, and performance. If you still have questions about the best tires for your vehicle after reading, talk to a professional at a repair shop you can trust.  The knowledgeable staff at Hansma Automotive can effectively address any of your concerns.

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Type of Tire
The letter "P" at the beginning of the alphanumeric code on the sidewall of the tire denotes that this tire's class is "Passenger" - intended for passenger vehicles. The letters "LT" found either at the beginning or the end of the tire size mean that the tire is meant for light trucks. If no letter is present then it means that it is a European metric tire. European metric tires are generally designed to have a higher load capacity than "P" metric tires, however their sizes are similar. Therefore a P195 tire could be replaced by a 195 because they are very close in size and the 195 has a greater load carrying capacity.

Tire Width
The next three-digit number tells you the tire's size in millimeters. In the picture below, the tire would be 215 mm wide measured from sidewall to sidewall.

Aspect Ratio
The next number found in the series after the slash gives the tire's aspect ratio. This is the ratio of the height of the tire's cross-section to its width. In other words, the height of the above tire's sidewall is 65% of its width.

Tire Construction
The "R" means that the above tire has a radial tire construction. Radial means that the tire was made up of layers which run "radially" across the width of the tire.

Wheel Diameter
The final number in this code denotes the diameter of the wheel's rim which the tire is designed to fit. It is measured in inches from one end of the rim to the other. Therefore the above tire was meant to fit on 15 inch rims.

Load Index
The load index refers to the maximum load that a tire can safely carry when it is properly inflated. Most passenger vehicles have a load index between 75 and 105. It is important to keep the proper load index when replacing your tires. If you need advice or help to install new tires, contact us.

Speed Symbol
The speed symbol gives the speed rating of the tire. They range form "A" (the lowest) to "Y" (the highest). The ratings are not however in perfect alphabetical order. For example "H" comes between "U" and "V", perhaps because at one time "H" stood for high performance. Typically the higher the speed rating, the better the grip on the road and the more effective the stopping capabilities. However this also means that its tread life is reduced. For more information on speed ratings click here.

Having the proper tires on your vehicle is very important for your driving safety and performance.  If you are planning on purchasing new tires, make sure you get a professional you can trust to install them. For superior service from expert mechanics, come to Hansma Automotive. We're located at 88 Shoemaker Street, Kitchener.


Call or Text: 519-748-5533


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Posted on April 25, 2016 .