Tire Specifications

When most people buy tires, they generally go to a tire store like Discount Tire or NTB and ask the guys behind the counter for assistance. The employees then go out to your vehicle, look at the tire specifications, and offer you tire deals that don't mean much to you. Hopefully with this page, you'll no longer be in the dark as to what the tire specifications really mean, and understand how finding a tire that meets your specifications will improve your driving.

The Numbers

tirespecmap.gif

As you look at the numbers on a tire it can be really confusing as to what part means what spec. So in our example we'll be referring to the image you see to the right with the specification read out of "P215/65 R15 89H". Common to the Wiki, we will be focusing on information directly related to Honda Accords; or in this case passenger vehicles as opposed to light/heavy duty trucks.

For more detailed explanation of the codes referenced on this page, see the section entitled Specification Charts

P:
This simply means that the tire is rated for passenger vehicles only. The P-metric is the U.S. version of a metric tire-sizing system.

215:
This is the section width of the tire in millimeters from sidewall to sidewall when fitted on the recommended rim.

65:
This is the aspect ratio of the tire, which is a ratio of height to width. This particular tire's height is 65% of its width.

R:
This indicates that this tire is built with a Radial construction. Other types of construction are indicated by the letter "B" for Belted Bias construction, and the letter "D" for Diagonal Bias construction.

15:
This is the diameter of the wheel in inches.

89:
This is called the load index (see Specification Charts). Different numbers correspond to different maximum loads. This particular tire has an industry-standard maximum load of 1,279 lbs.

H:
This is the speed rating of the tire (see Specification Charts). This particular tire has an industry-standard maximum service speed of 130 mph. Some tires use an older European system that features the speed rating in the size description of the tire.

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