Bicycle tires come in a wide range of sizes. The size of the tire is usually written on the sidewall of the tire, and it is represented by a series of numbers and letters. For example, a common size for a road bike tire is 700c x 23mm. The 700c refers to the diameter of the tire in millimeters, while the 23mm refers to the width of the tire in millimeters.
To read a bicycle tire size, start by finding the diameter and width of the tire. The diameter is always the first number, while the width is always the second number. For example, in the size 700c x 23mm, the diameter is 700mm and the width is 23mm.
Once you know the diameter and width of the tire, you can determine the circumference of the tire. To do this, simply multiply the diameter by 3.14. For example, the circumference of a 700c tire would be 700mm x 3