What Do The Numbers On Tires Mean? Tire Sizes Explained

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Have you ever wondered, "What do the numbers on tires mean?" In this post, you will find these mysterious alphanumeric codes explained. 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.

What Do The Numbers On Tires Mean? Tire Sizes Explained

It is quite easy to understand the series of numbers and letters on your tires once you know what everything means. The alphanumeric code provides you with important information about the tire's type, size, and performance.

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 millimetres. In the picture below, the tire would be 215 mm wide measured from sidewall to sidewall.

Courtesy: Wikimedia Commons

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 from "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.

Here’s a handy video that explains all of the above:

Trust Hansma With Your Tires!

Having the proper tires on your vehicle is very important for your driving safety and performance. If you are planning to purchase new tires, make sure you get a professional you can trust to install them.

Hansma Automotive is committed to serving you, our customer, with professional tire service at a reasonable cost. We stand on sound business principles and uphold high ethical standards. Our goal is to make your automotive repair experience friendly and successful.

"A few months back I was in a tight spot...I needed to commute to Toronto for work the next day and we had just gotten a down pour of snow and ice and I had not had a chance to get my winter tires put on. I started calling everyplace I could think of to try and get my snow tires installed but no one would give me the time of day (it turns out lots of people had not gotten their tires on yet)...then I called Hansma. Hansma got me in, changed my tires and put me back on the road in time for work the next day. The service, the price, and the work was all top notch. Thanks, Guys." 
- Joshua

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For superior service from expert mechanics, come to Hansma Automotive. We're located at 88 Shoemaker Street, Kitchener.

Posted on April 25, 2016 .