# How To Measure A Bike Rim

### Next multiple the radius by 2 to get the diameter.

How to measure a bike rim. The complete bicycle tire size guide. This kind is usually inaccurate because the fabric stretches. After measuring you can refer to a bike size chart as provided in this article to find your child s suitable bike size. To measure a bicycle wheel start by standing the bike upright by leaning it against a wall or using the kickstand.

The calculation here will give you your bike s frame size. Step 2 locate your measurement in inches or millimeters on a bicycle tire chart and match it to the corresponding rim size. To measure the inseam you need a yardstick and a medium sized book. If it is just the frame this will be the center point in the bottom bracket shell.

Bike frame sizes are measured in the same way for all styles of bicycle. As we will learn more later. A narrow metal tape measure 1 4 inch or 6 mm wide will fit into the well of the rim. In most cases riders usually go with whatever bike tire that will come along or leave the task to the local bike shop when it s time to replace or upgrade a tire.

The size of the bike tire is one of the commonly ignored aspects among the casual riders. Then use a tape measure to measure the distance from the ground underneath the tire to the center of the wheel to get the radius. Measure the distance between the wheel s hub or axle assembly and the outer edge of the wheel s rim. 1 with your child standing with his back against the wall align the book vertically on the wall between your child s legs up to the crotch area.

The wheel size is based on the diameter of the tire see below and as each tire size gets larger so does the size of the bicycle frame. Many mountain bikes have a 26 inch wheel again meaning the rim plus tire but you can determine for sure using one of two methods. Also the rim s diameter expressed in this manner coincides with the inner diameter of the tire. A wide metal tape measure won t fit into the well of the rim and and won t curve smoothly around the rim don t trust a fabric measuring tape as used in fitting clothing.

The most common sizes are. Therefore a 20 622 tire is a tire 20mm wide that fits on a rim with 622mm in diameter typically a road bike rim or a 29er one. Remember to get yourself a 150 psi portable pressure detection electric bike pump after knowing the right tires to buy for your bike. To measure your bike s frame size take a measuring tape and place the tape in the center bolt of your bike s cranks.