Bicycle Tire Size Chart — ETRTO, Metric & Imperial Conversion

Convert a size

Type a size in any notation — 37-622, 700x35C, 26x2.0 — and read it back in all three.

How to read a tire size

A bicycle tire carries up to three names for one size, and only one of them states fit. ETRTO — the standard also published as ISO 5775 — writes it as 37-622: section width in millimetres, then the bead seat diameter of the rim. Two tires fit the same wheel when that second number matches, and never otherwise.

The French notation, 700x35C, names a nominal outer diameter and a nominal width, neither measured. It is close enough to be useful and wrong often enough to be dangerous: tires printed 700x35C are usually 37-622, and 700x38C is usually 40-622. Where the two disagree, believe the ETRTO.

The imperial notation, 26 x 2.0, is the one that has caused the most trouble in cycling. It names the approximate outer diameter in inches, which depends on the tire as well as the rim, so several incompatible rim sizes have all been sold as "26-inch" over the years. The imperial column below is calculated from the ETRTO rather than copied from a sidewall, which is why it sometimes reads 26 x 1.97 where a tire is marked 26x2.0.

The short version

Match the second ETRTO number to your rim and you cannot go wrong. The first number is yours to choose, within the clearance your frame, fork and rim allow.

The chart

Jump to your wheel, or read the whole thing. Each ETRTO links to every tire made in that size. If you already know your size, the search tool is faster.

32-inch (686 mm rim)

2 sizes on a 686 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
55-686	32x2.15	—	55 mm	1
61-686	32x2.40	—	61 mm	4

700B / 28-inch (635 mm rim)

1 size on a 635 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
40-635	700x40B	28 x 1.57	40 mm	2

700C / 28-inch / 29-inch (622 mm rim)

43 sizes on a 622 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
18-622	700x18C	28 x 0.71	18 mm	1
20-622	700x20C	28 x 0.79	20 mm	3
22-622	700x22C	28 x 0.87	22 mm	1
23-622	700x23C	28 x 0.91	23 mm	33
24-622	700x24C	28 x 0.94	24 mm	3
25-622	700x25C	28 x 0.98	25 mm	42
26-622	700x26C	28 x 1.02	26 mm	7
28-622	700x28C	28 x 1.10	28 mm	56
29-622	700x29C	28 x 1.14	29 mm	6
30-622	700x30C	28 x 1.18	30 mm	31
31-622	700x31C	28 x 1.22	31 mm	1
32-622	700x32C	28 x 1.26	32 mm	39
33-622	700x33C	28 x 1.30	33 mm	22
34-622	700x34C	28 x 1.34	34 mm	6
35-622	700x35C	28 x 1.38	35 mm	30
36-622	700x36C	28 x 1.42	36 mm	2
37-622	700x37C	28 x 1.46	37 mm	30
38-622	700x38C	28 x 1.50	38 mm	5
40-622	700x40C	28 x 1.57	40 mm	66
42-622	700x42C	28 x 1.65	42 mm	20
44-622	700x44C	28 x 1.73	44 mm	2
45-622	700x45C	28 x 1.77	45 mm	31
47-622	700x47C	28 x 1.85	47 mm	18
48-622	700x48C	28 x 1.89	48 mm	2
49-622	700x49C	28 x 1.93	49 mm	1
50-622	700x50C	28 x 1.97	50 mm	52
52-622	700x52C	28 x 2.05	52 mm	13
53-622	700x53C	28 x 2.09	53 mm	4
54-622	700x54C	28 x 2.13	54 mm	11
55-622	700x55C	28 x 2.17	55 mm	42
56-622	700x56C	28 x 2.20	56 mm	3
57-622	700x57C	28 x 2.24	57 mm	37
58-622	700x58C	28 x 2.28	58 mm	10
59-622	700x59C	28 x 2.32	59 mm	1
60-622	700x60C	28 x 2.36	60 mm	57
61-622	700x61C	28 x 2.40	61 mm	25
62-622	700x62C	28 x 2.44	62 mm	9
63-622	700x63C	28 x 2.48	63 mm	14
64-622	700x64C	28 x 2.52	64 mm	5
65-622	700x65C	28 x 2.56	65 mm	38
66-622	700x66C	28 x 2.60	66 mm	12
71-622	700x71C	28 x 2.80	71 mm	1
76-622	700x76C	28 x 2.99	76 mm	3

27-inch (630 mm rim)

3 sizes on a 630 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
22-630	27x1 1/8	27 x 0.87	22 mm	1
25-630	27x1 1/4	27 x 0.98	25 mm	1
32-630	27	27 x 1.26	32 mm	3

650B / 27.5-inch (584 mm rim)

31 sizes on a 584 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
25-584	650x25B	27.5 x 0.98	25 mm	1
28-584	650x28B	27.5 x 1.10	28 mm	2
30-584	650x30B	27.5 x 1.18	30 mm	2
32-584	650x32B	27.5 x 1.26	32 mm	1
33-584	650x33B	27.5 x 1.30	33 mm	2
35-584	650x35B	27.5 x 1.38	35 mm	2
40-584	650x40B	27.5 x 1.57	40 mm	5
42-584	650x42B	27.5 x 1.65	42 mm	1
44-584	650x44B	27.5 x 1.73	44 mm	2
45-584	650x45B	27.5 x 1.77	45 mm	1
47-584	650x47B	27.5 x 1.85	47 mm	10
48-584	650x48B	27.5 x 1.89	48 mm	1
49-584	650x49B	27.5 x 1.93	49 mm	1
50-584	650x50B	27.5 x 1.97	50 mm	18
52-584	650x52B	27.5 x 2.05	52 mm	6
53-584	650x53B	27.5 x 2.09	53 mm	2
54-584	650x54B	27.5 x 2.13	54 mm	11
55-584	650x55B	27.5 x 2.17	55 mm	20
56-584	650x56B	27.5 x 2.20	56 mm	3
57-584	650x57B	27.5 x 2.24	57 mm	18
58-584	650x58B	27.5 x 2.28	58 mm	12
59-584	650x59B	27.5 x 2.32	59 mm	1
60-584	650x60B	27.5 x 2.36	60 mm	45
61-584	650x61B	27.5 x 2.40	61 mm	20
62-584	650x62B	27.5 x 2.44	62 mm	10
63-584	650x63B	27.5 x 2.48	63 mm	14
64-584	650x64B	27.5 x 2.52	64 mm	3
65-584	650x65B	27.5 x 2.56	65 mm	42
66-584	650x66B	27.5 x 2.60	66 mm	13
70-584	650x70B	27.5 x 2.76	70 mm	9
71-584	650x71B	27.5 x 2.80	71 mm	7

650C / 26-inch (571 mm rim)

1 size on a 571 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
23-571	650x23C	26 x 0.91	23 mm	3

26-inch (559 mm rim)

28 sizes on a 559 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
23-559	26x7/8	26 x 0.91	23 mm	1
25-559	26x1.00	26 x 0.98	25 mm	3
28-559	26x1.10	26 x 1.10	28 mm	2
32-559	26x1.25	26 x 1.26	32 mm	1
35-559	26x1.35	26 x 1.38	35 mm	3
38-559	26x1.5	26 x 1.50	38 mm	1
40-559	26x1.50	26 x 1.57	40 mm	8
42-559	26x1.65	26 x 1.65	42 mm	2
44-559	26x1.75	26 x 1.73	44 mm	1
47-559	26x1.75	26 x 1.85	47 mm	20
48-559	26x1.9	26 x 1.89	48 mm	1
50-559	26x2.00	26 x 1.97	50 mm	22
52-559	26x2.35	26 x 2.05	52 mm	12
53-559	26x2.10	26 x 2.09	53 mm	2
54-559	26x2.10	26 x 2.13	54 mm	16
55-559	26x2.15	26 x 2.17	55 mm	21
56-559	26x2.20	26 x 2.20	56 mm	1
57-559	26x2.25	26 x 2.24	57 mm	15
58-559	26x2.30	26 x 2.28	58 mm	12
59-559	26x2.70	26 x 2.32	59 mm	1
60-559	26x2.35	26 x 2.36	60 mm	12
61-559	26x2.40	26 x 2.40	61 mm	5
62-559	26x2.40	26 x 2.44	62 mm	3
63-559	26x2.50	26 x 2.48	63 mm	3
65-559	26x2.60	26 x 2.56	65 mm	1
100-559	26x4.00	26 x 3.94	100 mm	1
120-559	26x4.80	26 x 4.72	120 mm	2
122-559	26x4.8	26 x 4.80	122 mm	1

24-inch (507 mm rim)

12 sizes on a 507 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
44-507	24x1.75	24 x 1.73	44 mm	4
47-507	24x1.75	24 x 1.85	47 mm	8
50-507	24x2.00	24 x 1.97	50 mm	6
54-507	24x2.10	24 x 2.13	54 mm	2
55-507	24x2.15	24 x 2.17	55 mm	4
56-507	24x2.20	24 x 2.20	56 mm	1
58-507	24x2.30	24 x 2.28	58 mm	1
60-507	24x2.35	24 x 2.36	60 mm	5
61-507	24x2.40	24 x 2.40	61 mm	3
62-507	24x2.40	24 x 2.44	62 mm	1
63-507	24x2.50	24 x 2.48	63 mm	1
65-507	24x2.60	24 x 2.56	65 mm	2

20-inch (451 mm rim)

4 sizes on a 451 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
25-451	20x1.00	20 x 0.98	25 mm	1
28-451	20x1 1/8	20 x 1.10	28 mm	2
30-451	20x1 3/8	20 x 1.18	30 mm	1
37-451	20x1 3/8	20 x 1.46	37 mm	5

20-inch (406 mm rim)

25 sizes on a 406 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
28-406	20x1.10	20 x 1.10	28 mm	4
32-406	20x1.35	20 x 1.26	32 mm	1
35-406	20x1.35	20 x 1.38	35 mm	2
37-406	20x1.40	20 x 1.46	37 mm	4
38-406	20x1.50	20 x 1.50	38 mm	1
40-406	20x1.50	20 x 1.57	40 mm	4
42-406	20x1.60	20 x 1.65	42 mm	2
44-406	20x1.75	20 x 1.73	44 mm	6
45-406	20x1.75	20 x 1.77	45 mm	2
47-406	20x1.75	20 x 1.85	47 mm	13
48-406	20x1.85	20 x 1.89	48 mm	4
49-406	20x1.95	20 x 1.93	49 mm	2
50-406	20x2.00	20 x 1.97	50 mm	7
53-406	20x2.10	20 x 2.09	53 mm	8
54-406	20x2.00	20 x 2.13	54 mm	3
55-406	20x2.15	20 x 2.17	55 mm	8
56-406	20x2.20	20 x 2.20	56 mm	3
57-406	20x2.25	20 x 2.24	57 mm	2
58-406	20x2.30	20 x 2.28	58 mm	4
60-406	20x2.40	20 x 2.36	60 mm	5
61-406	20x2.40	20 x 2.40	61 mm	3
62-406	20x2.40	20 x 2.44	62 mm	4
65-406	20x2.60	20 x 2.56	65 mm	1
70-406	20x2.80	20 x 2.76	70 mm	1
100-406	20x4.00	20 x 3.94	100 mm	2

16-inch (349 mm rim)

3 sizes on a 349 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
30-349	16x1.20	16 x 1.18	30 mm	1
32-349	16x1 1/4	16 x 1.26	32 mm	1
35-349	16x1.35	16 x 1.38	35 mm	3

16-inch (305 mm rim)

6 sizes on a 305 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-305	16x1.40	16 x 1.46	37 mm	1
40-305	16x1.50	16 x 1.57	40 mm	1
44-305	16x1.75	16 x 1.73	44 mm	1
47-305	16x1.75	16 x 1.85	47 mm	5
50-305	16x2.00	16 x 1.97	50 mm	2
55-305	16x2.15	16 x 2.17	55 mm	2

12-inch (203 mm rim)

4 sizes on a 203 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
40-203	12x1.50	12 x 1.57	40 mm	1
47-203	12x1.75	12 x 1.85	47 mm	2
50-203	12x2.00	12 x 1.97	50 mm	3
62-203	12 1/2x2 1/4	12 x 2.44	62 mm	1

590 mm rim

2 sizes on a 590 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
25-590	650x25A	—	25 mm	3
37-590	650x37A	—	37 mm	2

541 mm rim

1 size on a 541 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-541	600A	—	37 mm	1

540 mm rim

4 sizes on a 540 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
25-540	24x1.00	—	25 mm	6
28-540	24x1.10	—	28 mm	1
32-540	24x1 3/8	—	32 mm	1
37-540	24x1 3/8	—	37 mm	2

501 mm rim

1 size on a 501 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
25-501	22x1.00 B.S.	—	25 mm	1

490 mm rim

1 size on a 490 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-490	550A	—	37 mm	1

489 mm rim

1 size on a 489 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
25-489	22x1.00	—	25 mm	2

440 mm rim

1 size on a 440 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-440	500A	—	37 mm	1

390 mm rim

1 size on a 390 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-390	450A	—	37 mm	1

355 mm rim

5 sizes on a 355 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
32-355	18x1.25	—	32 mm	1
40-355	18x1.50	—	40 mm	2
47-355	18x1.85	—	47 mm	1
50-355	18x2.00	—	50 mm	1
55-355	18x2.15	—	55 mm	1

340 mm rim

1 size on a 340 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-340	400A	—	37 mm	1

288 mm rim

2 sizes on a 288 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-288	14x1 3/8	—	37 mm	1
47-288	14x1.75	—	47 mm	1

254 mm rim

3 sizes on a 254 mm rim. Every size here mounts on the same wheel — only the width changes.

ETRTO	Sold as	Imperial	Width	Tires
37-254	14x1.40	—	37 mm	1
40-254	14x1.50	—	40 mm	1
50-254	14x2.00	—	50 mm	1

Keep going

Browse all sizes to see how many tires each one has, or all tire models for every size a given model is made in. If you already know your size, the search tool filters by brand, type, tubeless and e-bike rating.