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How to Measure Bike Tire & Wheel Circumference

an image showing different methods of how to measure the circumference of a bike tire

The circumference of a bike wheel is defined as the distance around the outside of the wheel. This distance includes the additional width that a tire brings to the wheel.

As you’re probably aware, wheel circumference is an important measurement for calibrating and ensuring the accuracy of a bike computer.

A bike computer, often referred to as a cyclometer, is a device that can provide detailed statistics on your bike rides, including the speed of your ride and the distance covered.

The majority of bike computers rely on counting a wheel’s rotations. So inputting the correct circumference is vital for accurate estimates of your speed and distance travelled.

To obtain the most accurate ride data possible, here are three easy ways to measure your wheel’s circumference.

For all of the below methods, ensure that your tire pressure is the same level you ride at.

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    At the bottom of the article, I’ve also included a bike tire circumference chart that you can use to verify the circumference of any bike tire. 

    Because cyclists have different preferences for tire pressure (PSI) and ride tires with varying amounts of wear, it’s essential to measure the circumference of your own tire.

    Whilst a few millimetres of inaccuracy may seem marginal. However, over the duration of a long bike ride, any inaccuracy in tire circumference can significantly impact the accuracy of the data your bike computer provides. 

    The 3 Best Methods for Measure Bike Tire Circumference

    Method 1 - Diameter of Wheel Multiplied By Pi

    How to measure bike wheel for tire size

    This method involves calculations you’ll probably want to use a calculator for.

    1. Measure the radius of your bicycle wheel, from the lowest point of tire contact with the floor to the centre of your wheel skewer or thru-axle.
    2. Multiply your wheel radius by 2 to find your total wheel diameter.
    3. Multiply the wheel diameter by Pi (diameter x 3.14). 
    4. This final result is the circumference of your bike tire.

    Formula for measuring bike wheel circumference: wheel diameter x 3.14 = wheel circumference.

    Method 2 - Dot to Dot (tape to tape)

    An image showing how to measure bike wheel circumference

    The dot to dot method is very simple but can be inaccurate if the steps below aren’t followed closely.

    1. Stretch your tape measure to around four meters in a straight line and lay it along the ground.
    2. Apply a dot of washable/non-staining paint to the centre of your bike tire.
    3. Roll your bike parallel to the tape measure making sure it travels in a straight line.
    4. Once two paint dots are on the ground, stop rolling and leave your bike to one side.
    5. Using your tape measure, measure the distance between the two paint dots—the distance between these two spots to determine your wheel circumference. 

    Method 3 - Wrap a Piece of String

    How to measure a bike wheel for a bike computer
    1. This method is significantly easier if you have an assistant to help you out. Otherwise, it can be quite fiddly!
    2. Take a ball of string and unwind it, so you have at least three meters unwound.
    3. Place one end of the string on the centre of the tire and hold it in place. 
    4. Ask your partner to wrap the string around the tire, ensuring it’s wrapped in a straight line. 
    5. Once the string returns to the starting position, either cut or mark the string where the two ends meet.
    6. Finally, use a tape measure to measure the total length of the piece of string. 
    7. The length of this piece of string is the circumference of your bike tire!

    Bike Tire Circumference Chart

    If you could find your tire size information on the side of your tire, search it below, and the table will reveal the standard circumference of tires of that size. 

    This bike tire circumference chart is accurate and uses data on the circumferences of standardized tires sold worldwide. 

    It’s important to understand, though, that there will always be a slight difference in circumference for each rider.

    Some cyclists prefer riding with a lower PSI, which decreases tire circumference, whilst others will be riding morn worn tires.

    To ensure you enter the most accurate figure into your bike computer, I recommend using one of the methods above, as this will provide you with the most precise measurement.

    After all, there’s no point in having a bike computer if it isn’t correctly calibrated.

    Tire Size ISO Size Circumference (meters) Circumference (mm)
    700 x 18C 18-622 2.07 2070
    700 x 19C 19-622 2.08 2080
    700 x 20C 20-622 2.086 2086
    700 x 23C 23-622 2.096 2096
    700 x 25C 25-622 2.105 2105
    700C Tubular - 2.13 2130
    700 x 28C 28-622 2.136 2136
    700 x 30C 30-622 2.146 2146
    700 x 32C 32-622 2.155 2155
    700 x 35C 35-622 2.168 2168
    700 x 38C 38-622 2.18 2180
    700 x 40C 40-622 2.2 2200
    700 x 44C 44-622 2.235 2235
    700 x 45C 45-622 2.242 2242
    700 x 47C 47-622 2.268 2268
    650 x 20C 20-571 1.938 1938
    650 x 23C 23-571 1.944 1944
    650 x 35A 37-590 2.09 2090
    650 x 38B 40-584 2.105 2105
    650 x 38A 40-590 2.125 2125
    12" x 1.75" 47-203 0.935 935
    12" x 1.95" 54-203 0.94 940
    14" x 1.50" 40-254 1.02 1020
    14" x 1.75" 47-254 1.055 1055
    16" x 1.50" 40-305 1.185 1185
    16" x 1.75" 47-305 1.195 1195
    16" x 2.00" 54-305 1.245 1245
    16" x 1-1/8" 28-349 1.29 1290
    16" x 1-3/8" 37-349 1.3 1300
    18" x 1.50" 40-355 1.34 1340
    18" x 1.75" 47-355 1.35 1350
    20" x 1.25" 32-406 1.45 1450
    20" x 1.35" 35-406 1.46 1460
    20" x 1.50" 40-406 1.49 1490
    20" x 1.75" 47-406 1.515 1515
    20" x 1.95" 50-406 1.565 1565
    20" x 1-1/8" 28-451 1.545 1545
    20" x 1-3/8" 37-451 1.615 1615
    22" x 1-3/8" 37-501 1.77 1770
    22" x 1-1/2" 40-501 1.785 1785
    24" x 3/4" Tubular - 1.785 1785
    24" x 1" 25-520 1.753 1753
    24" x 1-1/8" 28-540 1.795 1795
    24" x 1-1/4" 32-540 1.905 1905
    24" x 1.75" 47-507 1.89 1890
    24" x 2.00" 50-507 1.925 1925
    24" x 2.125" 54-507 1.965 1965
    26" x 7/8" Tubular - 1.92 1920
    26" x 1.25" 32-559 1.95 1950
    26" x 1.40" 37-559 2.005 2005
    26" x 1.50" 40-559 2.01 2010
    26" x 1.75" 47-559 2.023 2023
    26" x 1.95" 50-559 2.05 2050
    26" x 2.00" 52-559 2.055 2055
    26" x 2.1" 54-559 2.068 2068
    26" x 2.125" 57-559 2.07 2070
    26" x 2.35" 58-559 2.083 2083
    26" x 3.00" 75-559 2.17 2170
    26" x 1-1.0" 25-559 1.913 1913
    26" x 1" 25-571 1.952 1952
    26" x 1-1/8" 28-590 1.97 1970
    26" x 1-3/8" 37-590 2.068 2068
    26" x 1-1/2" 37-584 2.1 2100
    27" x 1" 25-630 2.145 2145
    27" x 1-1/8" 28-630 2.155 2155
    27" x 1-1/4" 32-630 2.161 2161
    27" x 1-3/8" 37-630 2.169 2169
    27.5" x 1.50" 40-584 2.079 2079
    27.5" x 1.95" 50-584 2.09 2090
    27.5" x 2.10" 54-584 2.148 2148
    27.5" x 2.25" 57-584 2.182 2182
    29" x 2.25" 58-622 2.281 2281
    29" x 2.1" 54-622 2.288 2288
    29" x 2.2" 56-622 2.298 2298
    29" x 2.3" 60-622 2.326 2326

    Conclusion - How to Measure The Circumference of a Bike Tire

    The information found above should have helped you correctly calibrate your bike computer. 

    However, if for any reason you were unable to measure the circumference of your bike tire or didn’t understand something in this article, leave me a comment below, and I’ll get straight back to you. 

    If you’re looking for a more detailed guide on bike wheel sizes, you can read the complete guide on wheel sizing here

    As always, make sure you’re using a good quality bike lock to secure your bike when leaving it unattended. 

    Lock it or lose it.

    Ciao for now!

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    Hello! My name’s James, I’m an avid cyclist and the lead editor of BikeLockWiki.

    I’ve invested over four years into researching & studying bicycle security. Now I want to share the information I’ve learnt, for free, with the online cycling community.

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