Bike tire sizing is one of the most ignored aspects among casual riders.
Most riders just kind of go along with whatever comes with their bike, or leave things up to their local bike shop whenever it’s time for a replacement or upgrade.
Things can get a little tricky if you’re doing things one your own, however. If you’re someone who plans on shopping online for new tires, or if you’re considering changing sizes, it’s obviously a requirement to know what the sizes are in the first place.
Most every tire has the size printed on the outside, but these numbers can wear off over time, so if you don’t have your sizes memorized, you may be in trouble if you don’t know how to measure.
Measuring a tire is actually much easier than you think, and there are quite a few different way to do it. This post will walk you through a common method.
Wait...What do the Numbers Mean?
Before measuring, it’s good to know what the numbers indicate in the first place. Bicycle tire measurements have two different parts.
The larger number is the tire diameter, while the smaller number is the tire width. This is commonly done using inches, although millimeters can be used as well.
Different bike types use vastly different sizes. Most tire diameters generally fall between 12 to 26 inches, with tire widths normally ranging from 1.75 to 2.215 inches.
Ok, onto the actual measuring.
Stand the bike up using a kickstand, or just lean it against a wall.
Step 2: Diameter
Place a tape measure against the center of the bicycle wheel, and then extend the tape in a straight line towards the tire’s outer edge.
If you’re using traditional sizing, all you need to do is double the length that you just measured, and you have the diameter.
(Keep in mind that tire diameters are almost always whole numbers. So, if your measurement comes out to something like 25.8, the actual diameter is really just 26 inches.)
Step 3: Width
Measuring width is just as easy. Take your tape measure, and place it on flat surface across the tire's tread going from one side to the other side.
Now all that’s left to do is to combine the measurements. Standard bike tire sizes place the diameter first and the width second. So, if your diameter was 26 inches, and the width came out to 2.2 inches, the printed measurement would be 26 x 2.2.
See? That wasn’t as hard as it initially seemed. You should now be able to accurately measure your bike’s tires whenever the need arises.
If you’re looking to use different sizes than what originally came on your bike, check to make sure your fork and frame can accommodate the size.