What is Tire Size and How to Find it For Your Own Tire

What is Tire Size and How to Find it For Your Own Tire April 21, 2016, 6:25 a.m.

An extremely important part for the optimized performance of your vehicle, whatever type that may be, is having well-fitting, high-quality tires. Upon purchasing a new vehicle, some individuals will opt to upgrade their tires to those that have off-roading capabilities, those that can handle the extremes of certain seasons and the corresponding weather, to those that have the capacity for enhanced performance or racing-type activities. For less informed individuals, it is easy to step into a tire store and to feel slightly overwhelmed by the excess in options that seem to be available. Well, we are writing this article to help you along in that process of searching and choosing new tires by providing you with the useful information surrounding the act of choosing a tire that matches in size to that which is required by your vehicle.

The first helpful tool to take advantage of is located on the tire itself. You may not have noticed this before reading this article, but each tire is equipped with a series of sizing related numbers that make up what is called a ‘sidewall.’ This sidewall gives multiple sets of measurements that, when combined, give you loads of information about the tire size. The first measurement you will see is a letter that will provide you with the metric, or tire type. For example, if you see a ‘P’ in this spot, you can infer that this tire is for a passenger car. The next measurement will be the tire width, in millimeters.

This number is an indication of the width of the tire from one wall to the opposite wall. The third measurement you will come across is the aspect ratio. This number is a percentage of the height of the tire’s cross section as compared to its width. Following this ratio will likely be either the letter ‘R’ or the letter ‘B.’ Each of these letters are indicators of construction and can inform you about how the tire layers were put together (either radially or with a bias construction). Next, you will find the rim diameter. This measures the width of the wheel from one end to the other. After rim diameter, you will find load index. This is information about the tire that can instruct you about the carrying capacity of this particular type of tire. Last in the tire size sidewall is the speed rating. This measurement that corresponds to the tire size offers you insight about the maximum service speed for a tire.

Choosing the correct size tire is essential for the safety of the driver and all passengers of your vehicle. With this new knowledge about how to do that, you are ready and well-informed when that next time comes around to change or upgrade your tires for your vehicle.

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