Bike Tyre Sizes explained: our complete guide

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.

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

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	-

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	-

27,5"
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

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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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	-

Bike Tyre Sizes explained: our complete guide

Where can you find your bike tyre size?

Understanding bike tyre sizes

ETRTO bicycle tyre size measurements

Imperial bicycle tyre size measurement

Metric bicycle tyre size measurements

Bike tyre size chart: How to convert a measurement ?

12"

14"

16"

17"

18"

20"

22"

24"

26"

27"

27,5"

28"

29"

Bicycle tyres for different types of bikes

Typical Road bikes

Typical MTBs and city bicycles

ETRTO is a common standard

Can I change the tyre size on my bike?

Find the right tyre