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
This method involves calculations you’ll probably want to use a calculator for.
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.
Multiply your wheel radius by 2 to find your total wheel diameter.
Multiply the wheel diameter by Pi (diameter x 3.14).
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)
The dot to dot method is very simple but can be inaccurate if the steps below aren’t followed closely.
Stretch your tape measure to around four meters in a straight line and lay it along the ground.
Apply a dot of washable/non-staining paint to the centre of your bike tire.
Roll your bike parallel to the tape measure making sure it travels in a straight line.
Once two paint dots are on the ground, stop rolling and leave your bike to one side.
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
This method is significantly easier if you have an assistant to help you out. Otherwise, it can be quite fiddly!
Take a ball of string and unwind it, so you have at least three meters unwound.
Place one end of the string on the centre of the tire and hold it in place.
Ask your partner to wrap the string around the tire, ensuring it’s wrapped in a straight line.
Once the string returns to the starting position, either cut or mark the string where the two ends meet.
Finally, use a tape measure to measure the total length of the piece of string.
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.
When factory tires wear out or you just want to put on other wheels, the question arises: what tire sizes will fit my car? The fact is that each car is designed for a certain wheel diameter and tread width. Usually, this information is contained on the back of the gas tank cap or in the operating documents. If you deviate from these sizes by more than 2-3 percent, then gas mileage will increase, the speedometer will begin to lie, and in case of a large difference, driving can become simply dangerous. nine0011
But how to choose the right size tires if there are some incomprehensible numbers written on the profile? Do not measure them with a ruler, by God. It is for these purposes that this tire calculator was created. It allows you to determine the difference between tires in centimeters, inches and percentages. In particular, with the tire calculator you can calculate and compare tire diameter, tread width, profile height and circumference. Additionally, the calculator detects potential differences in speedometer readings, ground clearance changes, and differences in revolutions per kilometer (or mile). nine0011
Calculator displays visual differences in tire diameter, profile, clearance and width. On the right side, a dynamic wheel pattern is generated, with a dotted pattern and parameters. At the top is a visual representation of the old tire (original size), and at the bottom is your potential new tire. The picture is displayed in two projections: lateral and frontal. Both can be downloaded to a computer in png format. To do this, right-click on the image and select "Save As...". nine0011
How to use the online tire calculator?
Using the virtual tire calculator is very easy. There are drop-down boxes in the upper left corner of the application. In the top row, you need to select the size of your original factory tire (or just the tires that are on your car at the moment). You can simply look at these indicators on the tire profile (side surface). The first field is the tire width in millimeters. The second field is the ratio of the profile height to the tire width in percent. The third field is the disc diameter in inches. nine0011
In the second row, you need to enter the size of the new tires, i. e. those tires that you are going to buy or have already bought. After that, click on the green "Calculate" button. The tire calculator will instantly calculate the differences between tires and display them in a table. Namely: diameter, width, circumference and height of the tire profile, the number of revolutions per kilometer and changes in ground clearance. The first two columns of the table will display the parameters of old and new tires, and the third column will show the nominal and percentage difference between them. Our recommendation will be displayed at the very bottom of the table. If the difference in diameters exceeds 3%, then we strongly do not recommend installing such tires, as this can be dangerous. nine0011
At the very bottom, you can see two speedometers that show the difference between the displayed and actual speed when changing tires. You can enter other values in the left speedometer using the arrows or directly from the keyboard. Changes will instantly be displayed on the right. By default, the difference is calculated at a speed of 60 kilometers per hour.
If you need to calculate in inches , then simply click on the inscription "Inches" in the switch, which is located under the green button. nine0011
Tire calculator online
To correctly calculate the tire parameters, compare tires, use our very convenient online calculator:
Transfer of tire parameters
/ R
mmmdeum shine
mmcmin
Tire profile height:
mmcmin
Rim diameter:
mmcmin
Tire circumference:
mmcminches
RPM:
Comparison of tires
Tire No. 1: / R Tire No. 2: / R
Tire No. tires:
Ground clearance change:
In the "Tyre #1" fields, enter the standard size for your car. It is usually indicated on a plate pasted in the driver's door opening.
In the "Tire #2" fields, enter the parameters of the tire you want to compare with the reference (tire #1).
The diameter of a new wheel (tire) must not differ by more than 3% from the wheel diameter set by the vehicle manufacturer. nine0011
Tire marking and decryption
Tire width for marking
Tire width ( W Tire ) is indicated by the first number in the marking in millimeters: 225 9033 /50 R16
How to calculate the height of the profile of the profile of the tire profile of the tire profile 9033
is indicated in the tire marking as the second number as a percentage of the first number (tire width): 225/ 50 R16
Thus, to determine it in millimeters, you need to calculate according to the following formula:
Formula
H profile in mm = (W tire ⋅ H profile in % ) / 100
Example
H profile = (205 ⋅ 55) / 100 = 113 mm = 11. 3 cm D or letter not specified): 225/50 R 16 .
This parameter is specified in inches , so if you want to convert it to centimeters, it must be multiplied by 2.54 .
Tire diameter according to the marking
Calculation of the wheel diameter is easy if you know the rim diameter and the profile height of the tire.
Formula
D tire = D disc + 2 ⋅ H profile
0332 205 /55 R16
We determine the height of the profile: H Profile = (205 ⋅ 55) / 100 = 11 ⋅ 2.54 = 40.64 cm
We determine the diameter of the tire: D Tire = 40.64 + 2 ⋅ 11.3 = 63.2 cm
Tire circumference
in order to calculate the length of the tire of the tire C 0333 you need to know its diameter D tires . The calculation is carried out according to the following formula:
Formula
C tire = π ⋅ D Tire , where π π π π π ≈ 3. 14
We take the tire diameter from the previous example D of the tire = 63.2 cm and determine the determination. tire circumference with marking: 205 / 55 R16
С tire = 63.2 ⋅ 3.14 = 198.44 cm
Number of wheel revolutions per 1 km
In order to determine the number of wheel revolutions at which it will overcome a distance of one kilometer, you need to know the outer circumference of the tire.
Formula
The number of revolutions = 100000 / C Tires in cm
Example
For a wheel length with tire circumference 198.44 cm We calculate the number of revolutions for 1 km:
The number of revolutions = 100000 / 198.4 = 503.9 ≈ 504 rev/km
How tire size affects the speedometer reading
If the wheel diameter is larger or smaller than the standard, then the speedometer readings will not reflect the actual speed of the car. So, for example, if the tire diameter is smaller than the standard one, then the speedometer will show the speed more than it actually is.
14 = wheel circumference.
086 
146 
235 
09 
02 
29 
46 
615 
795 
92 
05 
00" 
1 
50" 
1" 
5R14
2R14
1X11.6R15
1R15
5R15
5R15
6x8.5R16
1R16
6x10.4R16
6x14.4R16
5R16.5
5R17
6X5.3R17
3R17
3X10.8R17
5R17
3x10.4R18
9R18
8x11.2R18
3x10.4R19
7x8.9R19
8x11.6R20
9R20
5x10.4R20
5R20
3x10.4R21
3x10.4R22
5R22
8R23
5R24
4x12.4R30
Usually, this information is contained on the back of the gas tank cap or in the operating documents. If you deviate from these sizes by more than 2-3 percent, then gas mileage will increase, the speedometer will begin to lie, and in case of a large difference, driving can become simply dangerous. nine0011 
On the right side, a dynamic wheel pattern is generated, with a dotted pattern and parameters. At the top is a visual representation of the old tire (original size), and at the bottom is your potential new tire. The picture is displayed in two projections: lateral and frontal. Both can be downloaded to a computer in png format. To do this, right-click on the image and select "Save As...". nine0011 
e. those tires that you are going to buy or have already bought. After that, click on the green "Calculate" button. The tire calculator will instantly calculate the differences between tires and display them in a table. Namely: diameter, width, circumference and height of the tire profile, the number of revolutions per kilometer and changes in ground clearance. The first two columns of the table will display the parameters of old and new tires, and the third column will show the nominal and percentage difference between them. Our recommendation will be displayed at the very bottom of the table. If the difference in diameters exceeds 3%, then we strongly do not recommend installing such tires, as this can be dangerous. nine0011 
By default, the difference is calculated at a speed of 60 kilometers per hour. 
It is usually indicated on a plate pasted in the driver's door opening. 
3 cm D or letter not specified): 225/50 R 16 . 
14 
