Best 305/55 R21 Tires. Rims & Conversion Info

305/55 R21 in inches

305/55 R21 tires' overall diameter is 34.2 inches, tire width is 12 inches, the tire can be mounted on 21 inches wheel and the circumference is 107.4". With that parameters, we can calculate that it will take approximately 589.9 revolutions per mile.

305/55 R21 – what does it mean?

Parameter Meaning
305 The first number shows that the tire has a section width of 305 mm or approximately 12 inches.
55 The second number is the aspect ratio or sidewall height. In this case, it is 55%. It shows the height of the tire from the ground to the rim edge or the height of the tire's cross-section which is 55% of the width or ~ 168mm
R21 The letter R means this tire is radial. Most of all tires nowadays are radial. The number is the tire diameter in inches. It means that the tire will fit 21-inch wheels

If you want to know more about how to decipher information inscribed on your tires, including aspects such as the tire height, tire width, and the diameter of the wheel, this guide provides an in-depth look at how to read a tire sidewall. These measurements can reveal a wealth of information about your tire's specifications and suitability for your vehicle. Mastering these details will allow you to make informed decisions when buying or replacing your tires.