185/55R15 Tires & Tire Size

185/55R15 refers to the size of the tire. It’s a standard which is used by car and tire manufacturers. By having the standard, tire manufacturers are able to manufacture same size tires independently and users can buy same size tires from different manufacturers.

Here’s an explanation of what these metrics mean in practice:

185 The tire width is 185mm.
55 The aspect ratio of the tire is 55. Aspect ratio refers to the height of tire sidewall in relation to tire width in percentages.
R The letter in the middle refers to tire construction. Practically all tires sold for cars are radials.
Sometimes you also see tires with RF or ZR. RF indicates the tire is run flat, whereas ZR means the tire has speed rating higher than V. These tires are also radials, as the R indicates.
15 Rim diameter for the tire. 185/55R15 tire can be mounted only to a 15″ rims.

Best selling 185/55R15 tires

What is 185/55R15 tire size in inches?

Because the width of 185/55R15 tire is stated in millimeters and sidewall height in percentages, you have to make calculations to see what the true size of 185/55R15 is in inches. Luckily, we have made these calculations for you.In this table you can see size of 185/55R15 in inches, as well as few additional metrics:

  In inches In millimeters
Section Width 7.3″ 185mm
Sidewall height 4.0″ 102mm
Diameter / Height 23.0″ 585mm
Circumference 72.3″ 1836mm
Rim Diameter  15″  
Revolutions  876 per mile  545 per kilometer

Recommended Rim Sizes for 185/55R15 Tires

For 185/55R15 tires you need to have correct size rims to install the tires to. There are different width rims available in the market, and you can run into problems by installing 185/55R15 to a too wide or too narrow rim. Here are the recommended rim sizes for 185/55R15 tire:

Diameter Width Range
15″ 5-6.5″

185/55R15 – Variations

When you look at the tire code on 185/55R15 tires, you may see there are additional numbers and letters after the code 185/55R15. These numbers and letters refer to speed rating and load index of the tire. 185/55R15 has at least following variations available on the markets:

185/55R15 82H 185/55R15 82T 185/55R15 82V 185/55R15 86H 185/55R15 86T 185/55R15 87H