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Bike Tyre Sizes explained: our complete guide

Tips and advice bicycle

Bike tyre sizes can be expressed in three different ways, which causes confusion for cyclists. Let us help you identify and understand them so that you can easily choose the right tyres for your bike.

Where can you find your bike tyre size?

Finding your bike tyre sizes is quite easy since they are generally displayed on the tyre sidewall.

But what may be more confusing for some is what these tyre sizes correspond to, as they can be expressed in three different ways: ETRTO, imperial or metric measurements. Let us shed some light on each of them.

Understanding bike tyre sizes

  • Look for the numbers appearing on the tyre wall. You may need to spin the wheel round until you can see them, but they should still be quite easy to spot.
  • Your bike tyre size will probably be given in one of these three ways:

ETRTO bicycle tyre size measurements

Lettura delle misure gomme bici ETRTO

ETRTO bicycle tyre sizes appear as two digits separated by a dash: For example, 23-622, 25-622 or 28-622. The bike tyre size meaning is deciphered as follows:

23-622 / 25-622 / 47-622

The first digit is the tyre's width in millimetres at a given pressure and rim width. So, for instance, a typical road bike tyre size would display a smaller first pair of digits than a mountain bike (see mountain bike tyre sizes explained). MICHELIN follows the ETRTO recommendations.

23-622 / 25-622 / 47-622

For now, it’s important to understand that the second, three-digit number of an ETRTO bicycle tyre code relates to the rim ‘s seat diameter – again expressed in millimetres.

Keep in mind that the ETRTO measurement is the least used regarding the choice of your bicycle tyre.

Imperial bicycle tyre size measurement

Lettura delle misure gomme bici secondo il sistema imperiale

Some cyclists are more familiar with the imperial measurement. It is shown as a sequence of numbers like for example: 29 x 2.10 or 29 x 2.25. This type of measurement is usually used for mountain bike & city tyres.

29 x 2.10 or 29 x 2.25

Here, the bike tyre sizes are given in inches. The first number states the overall diameter (including the tyre) at a given pressure and rim width. The term 29 inches is often used to define the rim’s seat diameter. But that’s not the case, 29 inches is the overall diameter including the tyre.

29 x 2.10 or 29 x 2.25

The second number gives the width of the tyre mounted on the rim. So, in the examples above, 2.10 represents two-and-a-tenth inches, while 2.25 represents two-and-a-quarter inches at a given pressure and rim width.

Imperial bicycle tyre sizes sometimes have three numbers:

22 x 1 3/8 x 1 1/4

Misure copertone bici secondo il sistema imperiale a 3 cifre

When this happens, the first number always corresponds to the overall diameter in inches. Then, the second number give the tyre height and the final number represents the tyre's width. So, in the example given, the tyre would have a diameter of 22 inches, a height of one-and-three-eighths of an inch, and a width of one-and-a-quarter inches. That's why using MICHELIN's bike tyre size guide for cyclists can be very helpful for understanding bicycle tyre sizes

Metric bicycle tyre size measurements

Misure copertone bici con il sistema metrico

Last but not least, cyclists will often encounter tyres with markings such as 700 x 23C or as 700 x 28B, for example. This sizes, which are in millimetres, are often used for road tyres measurement.

700 x 23C or as 700 x 28B

Here, the first number is the overall diameter of the tyre at a given pressure and rim width.

700 x 23C or as 700 x 28B

The second part indicates the tyre's width in millimetres, plus the rim size expressed by a letter code.

Do you find all this complicated? Don’t worry! Since you can find different type of measurements for the same tyre, MICHELIN provides a bike size chart to help you convert one measurement to another, as we will explain below.

Bike tyre size chart: How to convert a measurement ?

In our bike tyre size chart, there are 3 columns, one for each measurement, which makes it easy to convert bike tyres sizes from metric to imperial / or vice versa. You can also use the bike tyre size chart to convert ETRTO (European Tyre and Rim Technical Organisation) bicycle tyre size data to one of the other types.

This way you will find the correspondence between the measurement indicated on your tyre and that indicated for the tyre you wish to buy.

Bike tyre size chart

12"

ETRTO

INCHES

MM

47-203

12 x 1.75

-

-

12 x 1.90

-

-

12 1/2 x 1.75

-

-

12 1/2 x 1.90

-

50-203

12 x 2.00

-

54-203

12 x 1.95

-

57-203

12 1/2 x 2 1/4

-

62-203

12 1/2 x 2 1/4

-

14"

ETRTO

INCHES

MM

47-254

14 x 1.75

-

-

14 x 1.90

-

50-254

14 x 2.00

-

40-279

14 x 1 1/2

350 x 38B

37-288

14 x 1 3/8

350 x 351

-

14 x 1 5/8 x 1 3/8

-

40-288

14 x 1 5/8

350 x 38A

44-288

14 x 1 5/8 x 1 3/8

350 x 42A

47-288

14 x 1.75

-

32-298

14 x 1 1/4

350 x 32A

16"

ETRTO

INCHES

MM

40-305

16 x 1.5

-

47-305

16 x 1.75

-

-

16 x 1.90

-

50-305

16 x 2.00

-

54-305

16 x 1.95

-

-

16 x 2.00

-

57-305

16 x 2.125

-

40-330

16 x 1 1/2

400 x 38B

28-340

-

400 x 30A

32-340

16 x 1 3/8 x 1 1/4

400 x 32A

37-340

16 x 1 3/8

400 x 35A

44-340

16 x 1 5/8

-

28-349

16 x 1 1/8

-

30-349

16 x 1.20

-

32-349

16 x 1 1/4

-

-

16 x 1.25

-

35-349

16 x 1.35

-

37-349

16 x 1 3/8

-

17"

ETRTO

INCHES

MM

32-357

17 x 1 1/4

-

32-369

17 x 1 1/4

-

18"

ETRTO

INCHES

MM

28-355

18 x 1 1/8

-

32-355

18 x 1.25

-

35-355

18 x 1.35

-

40-355

18 x 1.50

-

42-355

18 x 1.60

-

47-355

18 x 1.75

-

-

18 x 1.90

-

50-355

18 x 2.00

-

37-387

18 x 1 1/2

-

28-390

18 x 1 1/8

450 x 28A

37-390

18 x 1 3/8

450 x 35A

55-390

-

450 x 55A

57-390

-

450 x 55A

37-400

18 x 1 3/8

-

20"

ETRTO

INCHES

MM

54-400

20 x 2 x 1 3/4

-

23-406

20 x 0.90

-

25-406

20 x 1.00

-

28-406

20 x 1.10

-

-

20 x 1 1/8

-

32-406

20 x 1.25

-

35-406

20 x 1.35

-

37-406

20 x 1.40

-

-

20 x 1 3/8

-

40-406

20 x 1.50

-

42-406

20 x 1.60

-

44-406

20 x 1.50

-

-

20 x 1.625

-

47-406

20 x 1.75

-

-

20 x 1.90

-

50-406

20 x 2.00

-

54-406

20 x 2.10

-

-

20 x 2.00

-

55-406

20 x 2.15

-

57-406

20 x 2.25

-

-

20 x 2.125

-

60-406

20 x 2.35

-

54-428

20 x 2.00

-

40-432

20 x 1 1/2

-

37-438

20 x 1 3/8

-

40-438

20 x 1 3/8 x 1 1/2

-

28-440

-

500 x 28A

37-440

-

500 x 35A

40-440

20 x 1 1/2

500 x 38A

23-451

20 x 0.90

-

-

20 x 7/8

-

25-451

20 x 1.00

-

28-451

20 x 1 1/8

-

37-451

20 x 1 3/8

-

22"

ETRTO

INCHES

MM

50-489

22 x 2.00

-

28-490

-

500 x 28A

32-490

22 x 1 3/8 x 1 1/4

550 x 32A

37-490

22 x 1 3/8

550 x 35A

47-498

22 x 1 3/8 x 1 1/4

-

25-501

22 x 1.00 B.S

-

32-501

22 x 1 1/4

-

37-501

22 x 1 1/4

-

24"

ETRTO

INCHES

MM

40-507

24 x 1.50

-

44-507

24 x 1.625

-

-

24 x 1.75

-

47-507

24 x 1.75

-

-

24 x 1.85

-

-

24 x 1.90

-

50-507

24 x 2.00

-

-

24 x 1.90

-

-

24 x 2.125

-

54-507

24 x 2.10

-

55-507

24 x 2.15

-

57-507

24 x 2.25

-

-

24 x 2.125

-

60-507

24 x 2.35

-

62-507

24 x 2.40

-

23-520

24 x 0.90

-

-

24 x 7/8

-

44-531

24 x 1 5/8 x 1 1/2

-

40-534

24 x 1 1/2

-

20-540

24 x 3/4

-

23-540

24 x 0.90

-

-

24 x 7/8

-

25-540

24 x 1.00

-

30-540

24 x 1.20

-

32-540

24 x 1 3/8 x 1 1/4

-

37-540

24 x 1 3/8

-

40-540

24 x 1 3/8 x 1 1/2

-

22-541

-

-

25-541

-

600 x 25A

28-541

-

600 x 28A

32-541

24 x 1 3/8 x 1 1/4 NL

600 x 32A

37-541

-

600 x 35A

26"

ETRTO

INCHES

MM

20-559

-

-

23-559

26 x 0.90

-

-

26 x 7/8

-

25-559

26 x 1.00

-

28-559

26 x 1.10

-

30-559

26 x 1.20

-

32-559

26 x 1.25

-

35-559

26 x 1.35

-

37-559

26 x 1.40

-

-

26 x 1 5/8 x 1 3/8

-

40-559

26 x 1.50

-

42-559

26 x 1.60

-

44-559

26 x 1.625

-

44-559

26 x 1.75

-

47-559

26 x 1.75

-

-

26 x 1.80

-

-

26 x 1.85

-

-

26 x 1.90

-

-

26 x 2.00

-

50-559

26 x 2.00

-

-

26 x 1.90

-

-

26 x 1.95

-

52-559

26 x 2.00

-

54-559

26 x 2.10

-

-

26 x 1.95

-

-

26 x 2.125

-

57-559

26 x 2.25

-

-

26 x 2.125

-

-

26 x 2.20

-

58-559

26 x 2.35

-

62-559

26 x 2.40

-

-

26 x 2.50

-

64-559

26 x 2.50

-

65-559

26 x 2.60

-

70-559

26 x 2.75

-

75-559

26 x 3.00

-

95-559

26 x 3.70

-

-

26 x 3.80

-

100-559

26 x 4.00

-

115-559

26 x 4.50

-

120-559

26 x 4.80

-

20-571

26 x 3/4

-

23-571

26 x 7/8

650 x 23C

40-571

26 x 1 1/2 CS

650 x 38C

-

26 x 1 3/8 x 1 1/2 NL

-

47-571

26 x 1 3/4

650 x 45C

-

-

650 CS Confort

54-571

26 x 2 x 1 3/4

650 x 50C

20-590

26 x 3/4

650 x 20A

25-590

26 x 1.00

650 x 25A

28-590

26 x 1 3/8 x 1 1/8

650 x 28A

32-590

26 x 1 3/8 x 1 1/4

650 x 32A

37-590

26 x 1 3/8

650 x 35A

40-590

26 x 1.50

650 x 38A

-

26 x 1 3/8 x 1 1/2

-

42-590

26 x 1 5/8

650 x 40A

32-597

26 x 1 1/4

-

27"

ETRTO

INCHES

MM

40-609

27 x 1 1/2

-

20-630

27 x 3/4

-

22-630

27 x 7/8

-

25-630

27 x 1.00

-

-

27 x 1 1/16

-

28-630

27 x 1 1/8

-

32-630

27 x 1 1/4

-

35-630

27 x 1 3/8

-

27,5"

ETRTO

INCHES

MM

28-584

26 x 1 1/8 x 1 1/2

650 x 28B

32-584

-

650 x 32B

35-584

27.5 x 1.35

650B

-

26 x 1 3/8 x 1 1/2

650 x 35B

37-584

27.5 x 1.40

650B

-

26 x 1 1/2 x 1 3/8

650 x 35B

-

-

650 Standard

40-584

27.5 x 1.50

650B

-

26 x 1 5/8 x 1 1/2

650 x 38B

44-584

27.5 x 1.65

650B

-

26 x 1 5/8 x 1 2/2

650 x 42B

-

-

650B Semi-Confort

-

-

650B 1/2 Ballon

50-584

27.5 x 1.75

650B

52-584

27.5 x 2.00

650B

54-584

27.5 x 2.00

650B

-

27.5 x 2.10

-

55-584

26 x 1 1/2 x 2

650B

58-584

27.5 x 2.25

650B

61-584

27.5 x 2.35

650B

64-584

27.5 x 2.40

650B

66-584

27.5 x 2.50

650B

70-584

27.5 x 2.60

650B

71-584

27.5 x 2.75

650B

74-584

27.5 x 2.80

650B

75-584

27.5 x 2.90

650B

-

27.5 x 3.00

-7,5

28"

ETRTO

INCHES

MM

18-622

28 x 3/4

700 x 18C

19-622

-

700 x 19C

-

-

700 x 19

20-622

28 x 3/4

700 x 20C

22-622

28 x 7/8

700 x 22C

-

-

700 x 22

23-622

28 x 0.90

700 x 23C

-

28 x 7/8

-

24-622

-

700 x 24C

25-622

28 x 1.00

700 x 25C

-

28 x 1 1/16

-

26-622

-

700 x 26C

28-622

28 x 1.10

700 x 28C

-

28 x 1 5/8 x 1 1/8

-

30-622

28 x 1.20

700 x 30C

32-622

28 x 1.25

700 x 32C

-

28 x 1 5/8 x 1 1/4

-

33-622

28 x 1.30

700 x 33C

35-622

28 x 1.35

700 x 35C

37-622

28 x 1.40

700 x 35C

-

28 x 1 5/8 x 1 3/8

-

40-622

28 x 1.50

700 x 38C

-

28 x 1 5/8 x 1 1/2

-

42-622

28 x 1.60

700 x 40C

44-622

28 x 1.625

700 x 42C

47-622

28 x 1.75

 

50-622

28 x 2.00

-

-

29 x 2.00

-

-

28 x 1.90

-

55-622

28 x 2.15

-

-

29 x 2.15

-

60-622

28 x 2.35

-

-

29 x 2.35

-

32-635

28 x 1 1/2 x 1 1/8

770 x 28B

-

-

700 x 28B

-

-

700B Course

40-635

28 x 1 1/2

700 x 38B

-

28 x 1 1/2 x 1 5/8

700B Standard

44-635

28 x 1 5/8 x 1 1/2

700 x 42B

28-642

28 x 1 5/8 x 1 1/2

700 x 28A

37-624

28 x 1 3/8

700 x 35A

29"

ETRTO

INCHES

MM

50-622

29 x 2.00

-

52-622

29 x 2.00

-

-

28 x 2.00

-

54-622

29 x 2.10

-

-

28 x 2.10

-

55-622

29 x 2.15

-

-

28 x 2.15

-

55-622

29 x 2.25

-

58-622

29 x 2.35

-

61-622

29 x 2.40

-

-

28 x 2.35

-

75-622

29 x 3.00

-

Bicycle tyres for different types of bikes

MICHELIN produces tyres in bike tyre sizes suitable for almost all these different types of bicycles: cyclocross bikes, children's bikes, MTB and road bikes.

What's more, they are also available in different styles and with different tread patterns for many different applications.

Typical Road bikes

Road bicycle tyre sizes mostly use imperial measurements

For road bikes, bike tyre sizes are generally expressed in metric measurements. Although road bicycle tyre sizes can be expressed using the other systems, products like MICHELIN road racing tyres are always listed with their 700mm diameter appearing first. This is also standard practice for racing tyres, cyclocross tyres, everyday road bike tyres, training tyres as well as road bike tyres designed for harsher terrains – such as MICHELIN gravel tyres.

Typical MTBs and city bicycles

Mountain bike tyre sizes mostly use imperial measurements

However, it’s not the same for mountain bikes. An MTB tyre will typically display primary tyre dimensions in inches (Imperial measurement). This is the same for city bikes, a bicycle class which also includes trekking bikes as well as children's bicycles.

ETRTO is a common standard 

ETRTO is a useful multi-purpose system designed to work well for all types of bicycles. So, anything from a child’s first bicycle to a professional road bike will have tyre listings that use this system. But as said before, this type of measurement is the least used.

Can I change the tyre size on my bike?

Perhaps you are wondering whether you can change bicycle tyre sizes to suit different situations? It is sometimes possible to use different bike tyre sizes, provided the difference in size is only negligible. For example, some MTB riders choose slightly wider tyres on certain terrains.

However, the dimensions of your wheel rim will obviously remain the same, so it is usually best to stick to the recommended bike tyre size. Otherwise your bike’s performance could be severely impaired, which could even interfere with the operation of the brakes. Your bike tyre size depends on your bike specifications. So if you want to change your tyre size, MICHELIN advises you to contact a certified professional or your bike manufacturer.

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