How to Measure Bike Wheel Size

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Do you ever find yourself scratching your head when it comes to bike wheel size? Whether you’re buying new tires, tubes, rims, or spokes, or choosing the right bike for your height and riding style, knowing your bike wheel size is essential. But how do you measure it accurately and easily?

In this article, we’ll walk you through the steps to measure your bike wheel size like a pro.

How to Measure Bike Wheel Size with a Tape or Ruler

The  most common method applied is to use a tape measure or a ruler to measure the diameter and width of the wheel, i.e. the bike wheel size, manually.

The first step in measuring your bike wheel size is to determine the diameter of the wheel. This is the largest measurement of the wheel and is crucial for finding the right tire size. Here’s how you can do it:

1. Lay the bike on its side or prop it up on a stand to make it stable.

2. Ensure that the tire is fully inflated and in good condition.

3. Take a tape measure or a ruler and measure the distance from one end of the tire to the other end, along the center of the wheel. Make sure to align the tape measure or ruler with the wheel as closely as possible, avoiding any gaps or overlaps.

4. Note down the measurement. This is the diameter of your bike wheel.

The next step is to measure the width of the wheel. This is the smallest measurement of the wheel and is important for selecting the correct tire width. Here’s how you can do it:

1. Use the same stable setup as before, with the bike on its side or on a stand.

2. Take the tape measure or ruler and measure the distance from one edge of the wheel to the other edge, across the widest part of the tire.

3. Again, ensure that you align the tape measure or ruler with the wheel as closely as possible to get an accurate measurement.

4. Note down the measurement. This is the width of your bike wheel.

To ensure that you get the most accurate measurements of your bike wheel size, consider the following tips and tricks:

1. Use a flexible tape measure that can bend around the curve of the wheel, or a rigid ruler that can fit inside the rim.

2. Take multiple measurements and average them out for the most accurate result. Repeat the measurements at least twice to ensure consistency and accuracy.

3. Round up the measurements to the nearest whole number or fraction, depending on the unit of measurement you are using.

4. If you’re unsure about your measurements, consult the manufacturer’s specifications or a professional bike shop for further guidance.

How to Measure Bike Wheel Size without a Tape or Ruler

If you don’t have a tape measure or a ruler handy, don’t worry, there are other methods you can use to get an accurate measurement.

1. Using a String

One simple method is to use a string to measure your bike wheel size. Here’s how you can do it:

1. Wrap a string around the circumference of the tire, making sure it is snug but not too tight.

2. Mark the point where the string meets, forming a complete circle around the tire.

3. Lay the string flat on a surface and measure its length with another object, such as a coin. For reference:

  • a dollar coin that is 1.043 inches in diameter.
  • a half dollar coin that is 1.205 inches in diameter.
  • a quarter dollar coin that is 0.955 inch in diameter.
  • a dime coin that is 0.705 inch in diameter.
  • a 5-cent coin that is 0.835 inch in diameter.

4. Divide the length of the string by 3.14 to get the diameter of the tire.

5. Measure the width of the tire using the same object you used to measure the string.

6. Write down the diameter and width of the wheel.

Using a Bike Computer

If you have a bike computer that can measure the speed and distance of your bike, you can use it to measure your bike wheel size. Here’s how:

1. Reset the bike computer and set the wheel size to a default value, such as 26 inches.

2. Ride your bike for a short distance, such as 100 meters.

3. Note the speed and distance readings on the bike computer.

4. Divide the distance by the speed to get the time it took to ride the distance.

5. Use the following formula to calculate the wheel size: wheel size = distance / (time x 3.14 x 2).

6. Write down the measurement numbers.

Tips and Tricks

To ensure accurate and easy measurements, keep the following tips in mind:

1. Make sure the string is not stretched or bent when measuring the tire.

2. Ensure that your bike computer is calibrated and functioning properly.

3. Check that your tire is fully inflated and in good condition.

4. Repeat the measurements at least twice to ensure consistency and accuracy.

How to Convert the Measurements to the Standard Bike Wheel Size Format

Before diving into the conversion process, you need to decide which unit of measurement you want to use: inches or millimeters. Both are commonly used in the cycling world, so choose the one that you are most comfortable with or aligns with the specifications you’re working with.

If you’ve already measured the diameter and width of your bike’s tire but in a different unit of measurement, you’ll need to convert them to the unit you’ve chosen. Here’s how:

1. Convert inches to millimeters: Multiply the measurement in inches by 25.4 to get the equivalent measurement in millimeters.

2. Convert millimeters to inches: Divide the measurement in millimeters by 25.4 to get the equivalent measurement in inches.

Once you have the diameter and width of the tire in the desired unit of measurement, it’s time to write them down in the standard bike wheel size format, which is typically expressed as diameter x width. Let’s look at a couple of examples:

Example 1: If you measured the diameter and width of the tire in inches and they are 26 and 2.1 respectively, write down 26 x 2.1.

Example 2: If you measured the diameter and width of the tire in millimeters and they are 700 and 23 respectively, write down 700 x 23.

Converting measurements can sometimes be a bit tricky, but with these tips, you’ll be able to do it correctly and easily:

1. Use a calculator or conversion tool: If you’re not a math whiz, don’t worry! There are plenty of online calculators and conversion tools available that make the process a breeze.

2. Compare with common bike wheel sizes: To ensure you’ve converted the measurements correctly, it’s helpful to compare your results with the common bike wheel sizes for different types of bikes. Here are a few examples:

  • Road bikes typically have wheel sizes of 700C, 650C, or 27 inches.
  • Mountain bikes typically have wheel sizes of 26, 27.5, or 29 inches.
  • BMX bikes typically have wheel sizes of 20 or 24 inches.
  • Kids bikes typically have wheel sizes of 12, 14, 16, 18, or 20 inches.

By comparing your converted measurements with these standard sizes, you can ensure that you’ve got the right wheel size for your bike.

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AUTHOR

Randy Joycelyn

Randy is the founder and editor of Cycling Soigneur. He has been passionate about cycling since he was a kid. He has been riding bikes for over 10 years. Cycling has just become a part of life.

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