Size Markings

What do the various size markings on bicycle tires mean?

Nowadays, bicycle tire sizes are all marked according to ETRTO (European Tire and Rim Technical Organization) European standard.However, older English and French tire size dimensions are still used as well.

The ETRTO size specification 37-622 indicates the width of 37 mm and the tire inner diameter of 622 mm. This dimension is clear and allows for precise classification of the rim size.

Inch Marking (e.g. 28 x 1.40) states the approximate outer diameter (28 inches) and the tire width (1.40 inches). Inch marking such as 28 x 1 5/8 x 1 3/8 (approximate outer diameter x tire height x tire width) is also common.

Inch sizes are not precise and lack accuracy. For example, diameters 559 mm (MTB), 571 mm (Triathlon) and 590 mm (Touring) are all classified as 26 inch. Tires with diameters 622 mm and 635 mm are both classified as 28-inch. Oddly enough, tires with an inner diameter of 630 mm are classified as 27-inch.

These classifications originate from the time of tire brakes. In those days, the exact outer diameter of the tire was defined by the brake. Depending on tire width, various standards for the inner diameter applied.

Inch dimensions are widely used in both MTB sport and English language countries. Therefore, we will continue to use these specifications for all tires. In the future, only inch decimal measurements will be used e.g. 26 x 2.25. Experience tells us that nowadays very few users are familiar with the classical fractional inch dimensions such as, 28 x 1 5/8 x 1 3/8.

When the 29 inch MTB tire size was introduced a few years ago it had the same inner diameter of 622mm, known as 28" in Europe.
French size markings (e.g. 700 x 35C) give the approximate tire outer diameter (700 mm) and width (35mm). The letter at the end indicates the inner diameter of the tire. In this case, C stands for 622 mm.

French size markings are not used for all tire sizes, so, for example, it is not used for MTB sizes.

Size Designations Overview

  ETRTO Inch French
Size designation 37-622 28 x 1.40"
28 x 1 5/8 x 1 3/8"
700x35c
Outer diameter - Approx. 28" Approx. 700mm
Inner diameter 622 mm - -
Tire section width Approx. 37 mm Approx. 1.40"
Approx. 1 3/8"
Approx. 35 mm
Tire section height - Approx. 1 5/8" -


How many tire sizes are there?

The following table shows all common tire sizes This table lists, where applicable, a corresponding ETRTO-size for virtually every tire size.

  ETRTO Inch French
7" 47-93 7 x 1 3/4  
8" 47-94

20 x 47-50 8 x 2

 
50-94 200 x 50  
54-110 8 x 2 1/8 8 1/2 x 2  
32-137 8 x 1 1/4  
10" 54-152 44-194 10 x 2 10 x 1 5/8  
11" 47-222 11 x 13/4  
12" 47-203 12 1/2 x 1.75 12 1/2 x 1.90  
54-203 12 x 1.95  
57-203 12 1/2 x 2 1/4 R  
62-203 12 1/2 x 2 1/4  
32-239 12 1/2 x 1 3/8 x 1 1/4 300 x 32A
57-239 12 1/2 x 2 1/4 300 x 55A
14" 57-251 14 1/2 x 2 1/4 300 x 55A
47-254 14 x 1.75 14 x 1.90  
40-279 14 x 11/2 350 x 38B
37-288 14 x 1 5/8 x 1 3/8 350A 350A 350A Confort 350A Ballon 350A 1/2Ballon 350 x 32A
40-288 14 x 1 5/8 350 x 38A
44-288 14 x 1 5/8 x 1 3/8 350A 350 x 42A
32-298 14 x 1 1/4 350A 350 x 32A
16" 40-305 16 x 1.50  
47-305 16 x 1.75 16 x 1.90  
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 400A 400 x 32A
37-340 16 x 1 3/8 x 1 1/4 400 x 35A 400A Confort 400A Ballon 400A 1/2 Ballon
44-340 16 x 1 5/8  
28-349 16 x 11/8  
32-349 16 x 11/4 NL  
37-349 16 x 1 3/8  
17" 32-357 17 x 1 1/4  
37-369 17 x 1 1/4  
18" 28-355 18 x 1 1/8  
40-355 18 x 1.50  
47-355 18 x 1.75 18 x 1.90  
37-387 18 x 1 3/8  
40-387 18 x 1 1/2  
28-390 18 x 1 1/8 450 x 28A 450A
37-390 18 x 1 3/8 450 x 35A 450A 450A Confort 450A Ballon 450A 1/2Ballon
55-390   450 x 55A
57-390   450 x 55A 450A
37-400 18 x 1 3/8  
20" 54-400 20 x 2 x 1 3/4 20 x 2F4J  
28-406 20 x 1 1/8  
32-406 20 x 1.25  
35-406 20 x 1.35  
37-406 20 x 1 3/8  
40-406 20 x 1.50  
44-406 20 x 1.625  
47-406 20 x 1.75 20 x 1.90  
50-406 20 x 2.00  
54-406 20 x 2.00  
57-406 20 x 2.125  
54-428 20 x 2.00  
40-432 20 x 1 1/2  
37-438 20 x 1 3/8 500A
40-438 20 x 1 3/8 500 x 38A
28-440   500 x 28A 500A 500A Standard
40-440 20 x 1 1/2NL 500 x 38A
28-451 20 x 1 1/8  
37-451 20 x 1 3/8 B.S.  
22" 44-484 22 x 15/8 x 11/2  
25-489 22 x 1.00  
37-489 22 x 1 3/8 NL  
40-489 22 x 1 3/8 x 1 1/2  
50-489 22 x 2.00  
28-490   550 x 28A 550A 550A Standard
32-490 22 x 1 3/8 x 1 1/4 550 x 32A 550A
37-490 22 x 13/8 550 x 35A 550A Confort 550A Ballon 550A 1/2 Ballon
37-498 22 x 1 3/8 x 1 1/4  
32-501 22 x 1 1/4  
37-501 22 x 1 3/8  
24" 40-507 24 x 1.50  
44-507 24 x 1.625 24 x 1.75  
47-507 24 x 1.75 24 x 1.85/1.90  
49-507 24 x 1.85  
50-507 24 x 1.90/2.00 24 x 2.00 24 x 2.125  
54-507 24 x 2.10  
57-507 24 x 2.125 24 x 2.00  
60-507 24 x 2.35  
44-531 24 x 1 5/8 x 1 1/2  
40-534 24 x 1 1/2  
25-540 24 x 1.00  
32-540 24 x 1 3/8 x 1 1/4 24 x 1 3/8  
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 600A 600A Standard
32-541 24 x 1 3/8 x 1 1/4 N4 600 x 32A
37-541   600 x 35A 600A Confort 600A Ballon 600A 1/2 Ballon
26" 25-559 26 x 1.00  
35-559 26 x 1.35  
37-559 26 x 1 5/8 x 1 3/8 26 x 1.40  
40-559 26 x 1.50  
44-559 26 x 1.625 26 x 1.50/1.75  
47-559 26 x 1.75 26 x 1.85/1.90  
50-559 26 x 1.90 26 x 1.95 26 x 1.90/2.00 26 x 2.00/2.10  
54-559 26 x 1.95 26 x 2.10 26 x 2.125  
57-559 26 x 2.125 26 x 2.20/2.25  
60-559 26 x 2.35  
62-559 26 x 2.50  
20-571 26 x 3/4 650 x 20C
23-571 26 x 7/8 650 x 22C
40-571 26 x 1 1/2 CS 26 x 1 3/8 x 1 1/2 NL 26 x 1 5/8 x 1 1/2 650 x 35C 650 x 38C
47-571 26 x 1 3/4 650 CS confort 650 x 45C
54-571 26 x 2 x 1 3/4 650 x 50C
28-584 26 x 1 1/8 x 1 1/2 650 x 28B
32-584   650 x 32B
35-584 26 x 1 3/8 x 1 1/2 650 x 35B 650B Standard
37-584 26 x 1 1/2 x 1 3/8 26 x 1 1/2 650 x 35B
40-584 26 x 1 5/8 x 1 1/2 650 x 42B 650B Semi-Confort 650B 1/2 Ballon
20-590   650 x 20A
25-590 26 x 1 1/8, 1 1/4 26 x 1 3/8 - 1 1/4 650 x 32A
28-590 26 x 1 1/8 650 x 28A
32-590 26 x 1 1/4 26 x 1 3/8 x1 1/4 650 x 32A
35-590 26 x 1 3/8 650 x 35A
37-590 26 x 1 3/8 650 x 35A 650A
40-590 26 x 1.50 28 x 1 3/8 x 1 1/2 650 x 38A
44-590    
32-597 26 x 1 1/4  
27" 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 27 x 1 1/4 Fifty 27 x 1 1/4  
32-630 27 x 1 1/4  
28/32-630 27 x 1 1/4  
35-630 27 x 1 3/8  
28" 18-622 28 x 3/4 700 x 18C
19-622   700 x 19C
20-622 28 x 3/4 700 x 20C
22-622 28 x 7/8 700 x 22C
23-622 28 x 7/8 700 x 23C
25-622 28 x 1.00, 1 1/16 700 x 25C
30-622 28 x 1.20 700 x 28C
28-622 28 x 1 5/8 x 1 1/8 700 x 30C
32-622 28 x 15/8 x 11/4 700 x 32C 700C COURSE
35-622 28 x 15/8 x 13/8 700 x 35C
37-622 28 x 1 5/8 x 1 3/8 700 x 35C
40-622 28 x 1.50 28 x 1 5/8 x 1 1/2 700 x 38C
42-622 28 x 1.60 700 x 40C
44-622 28 x 1.625 700 x 42C
47-622 28 x 1.75 700 x 45C
50-622 28 x 1.90 28 x 2.00  
60-622 28 x 2.35  
32-635 28 x 1 1/2 x 1 1/8 770 x 28B 700 x 28B 770B COURSE
40-635 28 x 1 1/2 28 x 1 1/2 x 1 3/8 700 x 38B 700 x 35B 700 Standard 700B Standard
44-635 28 x 15/8 x 11/2 700 x 40/42B
28-642 28 x 1 3/8 x 1 1/8 700 x 28A
37-642 28 x 1 3/8 700 x 35A