How to Measure a Bike Tire

We hope you love the products we recommend. We may earn an affiliate commission when you buy through links on our site. Learn more

If you tend to fall into the category of new bike rider or casual bike rider, you might not realize that the measurement of your bike tire is important. You might have a bike and simply figured that the tire that came with the bike was exactly what you need. If you have had a tire replaced at a bike shop, then you might have simply decided to follow the advice of the employees without actually understanding anything about the bike tire or why the sizing is important. This is certainly understandable for casual riders and those who rely on the advice of others.

However, if you are looking to expand your knowledge and find the right tires for the job, things can be a bit more complicated. You are eventually going to need to learn more about tire sizes and how to measure a bike tire. Fortunately, it is not as hard as some people might imagine.

Before You Begin – Understand the Numbers

It is not going to do you much good to learn how to measure a bike tire if you have no idea what the numbers mean, so that seems like a good place to start. When it comes to tire measurements, there are two different elements. First, there is the tire diameter. This is the larger number that you will see when looking at tire sizes. The second number, which is smaller, is going to be the tire width. Mystery solved. Most of the time, you will find that the tires are measured in inches. However, they can also be measured in millimeters. The International Organization for Standardization, or ISO, developed a measurement system that uses millimeters. This is sometimes called the bead seat diameter.

You should learn how to convert millimeters to inches and vice versa. This way you will know what to choose if you are looking for tires and know the inch measurement you need, but the tires you are looking at are all in millimeters, for example.

Related: How to Treat Road Rash

How Do You Take the Measurements?

It’s easy, but you will want to make sure that the bike is standing up properly, and that you have inflated the tires to the proper pressure. Next, you are going to need to have a tape measure. Put it on the center of the wheel and then extend it to the outer edge of the tire. Double the length of this measurement, and you will have the diameter that you need.

Next, we move on to the width. It is even easier. You just take the tape measure and measure across the width of the tire tread.

Here’s an important tip to remember: the diameter of the wheel is measured only in whole numbers, while the width of the tires is not. Therefore, you could get an actual measurement of 25.7 inches on the diameter and 2.2 inches on the width. The actual bike tire measurement would then be 26” x 2.2”, and that measurement would be what you need to look for when you are getting a replacement tire.

Measuring a bike tire is going to be one of the easiest things that you do. If you haven’t measured your own bike tires yet, go out and practice, so you will know exactly what you need if you are looking for a replacement, or if you want to consider trying out a different size.