ISO 5775 is an international standard for labeling the size of bicycle tyres and rims. The system used was originally developped by the European Tyre and Rim Technical Organization (ETRTO). This racing bicycle is built using lightweight, shaped aluminum tubing and carbon fiber stays and forks. ...

Tyres

Wired-edge tyres

Wired-edge tyres can be mounted on straight-side or crotchet-type rims. Such tyres are designated with their nominal rim diameter and their nominal width, separated by a hyphen (-). Both are measured in millimeters. A typical example of a tyre marking according to ISO 5775-1 is: A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ...

32-597 inflate to 400 kPa

• The first number (nominal section width) is essentially the width of the inflated tire (minus any tread).

• The second number (nominal rim diameter) is the inner diameter of the tire when it is mounted on the rim. The corresponding circumference can be measured with a suitably narrow tape inside the rim.

• The recommended inflation pressure is marked in kilopascals.

The standard notes that the minimum inflation pressure recommended is 300 kPa for narrow tires (25 mm section width or less), 200 kPa for other sizes in normal highway service, and 150 kPa for off-the-road service. The pascal (symbol Pa) is the SI unit of pressure. ...

The inner width of the rim on which the tire is mounted should be about 65% of the tire's nominal section width for tires smaller than 30 mm and 55% for those larger.

The section height of a tire is usually identical to its section width (for tires less than 28 mm, 2.5 mm have to be added to the width to get the height). The overall diameter of the tire is then the rim diameter plus twice the tire's section height. The ISO 5775-1 standard also defines procedures for measuring tires and for calculating from the marking the maximum dimensions of a tire, which are needed by designers to determine clearance distances to other bicycle components.

The standard defines a set of nominal section widths for wired-edge tyres and lists recommended rim widths for each:

Older markings of wired-edge tyres can be converted to ISO 5775 designations with the help of the following table:

 Tire size | designation | Old marking (inch or using outer diameter in mm) -------------|----------------------------------------------------- 28-590 | 26 × 1 3/8 × 1 1/8 -------------|----------------------------------------------------- 28-622 | 28 × 1 5/8 × 1 1/8 700 × 28C | 28 × 1 5/8 × 1 1/4 × 1 1/8 700 C Carrera -------------|----------------------------------------------------- 28-630 | 27 × 1 1/4 fifty -------------|----------------------------------------------------- 28-635 | 700 B -------------|----------------------------------------------------- 28-642 | 28 × 1 3/8 × 1 1/8 700 × 28 A -------------|----------------------------------------------------- 32-239 | 12 × 1 3/8 × 1 1/4 300 × 32 -------------|----------------------------------------------------- 32-248 | 12 × 1 1/4 300 × 32 A -------------|----------------------------------------------------- 32-288 | 14 × 1 3/8 × 1 1/4 350 × 32 -------------|----------------------------------------------------- 32-298 | 14 × 1 1/4 350 × 32 A -------------|----------------------------------------------------- 32-340 | 16 × 1 3/8 × 1 1/4 400 A | 400 × 32 -------------|----------------------------------------------------- 32-349 | 16 × 1 1/4 NL 400 × 32 A -------------|----------------------------------------------------- 32-357 | 17 × 1 1/4 -------------|----------------------------------------------------- 32-369 | 16 × 1 1/4 -------------|----------------------------------------------------- 32-390 | 18 × 1 3/8 × 1 1/4 450 A | 450 × 32 -------------|----------------------------------------------------- 32-400 | 18 × 1 1/4 450 × 32A -------------|----------------------------------------------------- 32-438 | 500 × 32 ANL -------------|----------------------------------------------------- 32-440 | 20 × 1 3/8 × 1 1/4 500 A | 500 × 32 -------------|----------------------------------------------------- 32-451 | 20 × 1 1/4 500 × 32 A -------------|----------------------------------------------------- 32-489 | 550 × 32 ANL -------------|----------------------------------------------------- 32-490 | 22 × 1 3/8 × 1 1/4 550 A | 550 × 32 -------------|----------------------------------------------------- 32-501 | 22 × 1 1/4 550 × 32 A -------------|----------------------------------------------------- 32-508 | 22 × 1 1/4 × 1 -------------|----------------------------------------------------- 32-540 | 24-1 3/8 × 1 1/4 -------------|----------------------------------------------------- 32-541 | 24 × 1 3/8 × 1 1/4 NL 600 A | 600 × 32 A -------------|----------------------------------------------------- 32-547 | 24 × 1 1/4 -------------|----------------------------------------------------- 32-590 | 26 × 1 3/8 1 1/4 650 × 32A -------------|----------------------------------------------------- 32-597 | 26 × 1 1/4 -------------|----------------------------------------------------- 32-622 | 28 × 1 5/8 × 1 1/4 700 × 32C | 28 × 1 1/4 × 1 3/4 700 × C Course -------------|----------------------------------------------------- 32-630 | 27 × 1 1/4 -------------|----------------------------------------------------- 32-635 | 28 × 1 1/2 × 1 1/8 700 × 28 B | 700 B Course -------------|----------------------------------------------------- 37-288 | 350 A Comfort | 350 A 1/2 Balloon -------------|----------------------------------------------------- 37-298 | 14 × 1 3/8 -------------|----------------------------------------------------- 37-337 | 16 × 1 3/8 ANL -------------|----------------------------------------------------- 37-340 | 16 × 1 3/8 NL 400 A Comfort | 400 A 1/2 Balloon | 400 × 42 A | 400 × 35 A -------------|----------------------------------------------------- 37-349 | 16 × 1 3/8 NL -------------|----------------------------------------------------- 37-387 | 18 × 1 3/8 -------------|----------------------------------------------------- 37-390 | 450 A Comfort | 450 A 1/2 Balloon -------------|----------------------------------------------------- 37-400 | 18 × 1 3/8 -------------|----------------------------------------------------- 37-438 | 20 × 1 3/8NL -------------|----------------------------------------------------- 37-440 | 500 A Comfort | 500 A 1/2 Balloon -------------|----------------------------------------------------- 37-451 | 20 × 1 3/8 -------------|----------------------------------------------------- 37-489 | 22 × 1 3/8 NL -------------|----------------------------------------------------- 37-490 | 550 A Comfort | 550 A 1/2 Balloon -------------|----------------------------------------------------- 37-498 | 22 × 1 3/8 × 1 1/4 NL -------------|----------------------------------------------------- 37-501 | 22 × 1 3/8 -------------|----------------------------------------------------- 37-540 | 24 × 1 3/8 -------------|----------------------------------------------------- 37-541 | 600 A Comfort | 600 A 1/2 Balloon | 600 × 35 A -------------|----------------------------------------------------- 37-565 | 25 × 1 3/8 -------------|----------------------------------------------------- 37-584 | 26 × 1 1/2 × 1 3/8 | 26 × 1 3/8 × 1 1/2 -------------|----------------------------------------------------- 37-590 | 26 × 1 3/8 650 A | 650 × 35 A -------------|----------------------------------------------------- 37-622 | 28 × 1 5/8 × 1 3/8 700 × 35 C | 28 × 1 3/8 1 5/8 -------------|----------------------------------------------------- 37-642 | 28 × 1 3/8 700 × 35 A -------------|----------------------------------------------------- 40-279 | 14 × 1 1/2 350 × 38 B -------------|----------------------------------------------------- 40-288 | 14 × 1 1/2 NL 350 × 38 -------------|----------------------------------------------------- 40-330 | 16 × 1 1/2 400 × 38 B -------------|----------------------------------------------------- 40-432 | 20 × 1 1/2 -------------|----------------------------------------------------- 40-440 | 20 × 1 1/2 NL 500 × 38 -------------|----------------------------------------------------- 40-534 | 24 × 1 1/2 -------------|----------------------------------------------------- 40-540 | 24 × 1 3/8 × 1 1/2 | 24 × 1 1/2 × 1 3/8 -------------|----------------------------------------------------- 40-571 | 26 × 1 1/2 C.S. | 26 × 1 5/8 × 1 1/2NL -------------|----------------------------------------------------- 40-584 | 26 × 1 1/2 650 × 35 B | 650 × 38 B -------------|----------------------------------------------------- 40-590 | 26 × 1 3/8 × 1 1/2 NL -------------|----------------------------------------------------- 40-622 | 28 × 1 5/8 × 1 1/2 NL 700 × 38 C -------------|----------------------------------------------------- 40-635 | 28 × 1 1/2 × 1 3/8 700 B Standard | 28 × 1 1/2 700 × 35 B | 700 × 38 B -------------|----------------------------------------------------- 44-194 | 10 × 1 5/8 -------------|----------------------------------------------------- 44-288 | 14 × 1 3/8 × 1 5/8 350 A | 350 × 42A -------------|----------------------------------------------------- 44-340 | 16 × 1 5/8 -------------|----------------------------------------------------- 44-428 | 20 × 1 5/8 × 1 1/2 -------------|----------------------------------------------------- 44-484 | 22 × 1 5/8 × 1 1/2 -------------|----------------------------------------------------- 44-531 | 24 × 1 5/8 × 1 1/2 -------------|----------------------------------------------------- 44-584 | 26 × 1 1/2 × 1 5/8 650 B Semi-comfort | 26 × 1 5/8 × 1 1/2 650 B 1/2 Balloon | 26 × 1 3/4 × 1 1/2 650 × 42B -------------|----------------------------------------------------- 44-622 | 28 × 1 5/8 700 × 42 C -------------|----------------------------------------------------- 44-635 | 28 × 1 5/8 × 1 1/2 | 28 × 1 1/2 × 1 5/8 -------------|----------------------------------------------------- 47-203 | 12 1/2 × 1.75 × 2 1/4 -------------|----------------------------------------------------- 47-222 | 11 × 1 3/4 -------------|----------------------------------------------------- 47-305 | 16 × 1.75 × 2 -------------|----------------------------------------------------- 47-317 | 16 × 1 3/4 -------------|----------------------------------------------------- 47-355 | 18 × 1.75 × 2 -------------|----------------------------------------------------- 47-406 | 20 × 1.75 × 2 | 20 × 1.75 -------------|----------------------------------------------------- 47-419 | 20 × 1 3/4 -------------|----------------------------------------------------- 47-501 T | 24 × 1 3/4 R 600 × 45 C -------------|----------------------------------------------------- 47-507 | 24 × 1.75 × 2 | 24 × 1.75 -------------|----------------------------------------------------- 47-520 | 24 × 1 3/4 -------------|----------------------------------------------------- 47-559 | 26 × 1.75 × 2 | 26 × 1.75 -------------|----------------------------------------------------- 47-571 | 26 × 1 3/4 650 × 45 C | 26 × 1 5/8 650 C S.C. -------------|----------------------------------------------------- 45-584 | 26 × 1.75 × 1 1/2 650 × 45 B | 26 × 1 1/2 × 1 3/4 -------------|----------------------------------------------------- 47-622 | 28 × 1 3/4 700 × 45 C | 28 × 1.75 | 28 × 15/8 1 3/4 -------------|----------------------------------------------------- 54-298 | 14 × 2 × 1 3/4 -------------|----------------------------------------------------- 54-305 | 16 × 2 -------------|----------------------------------------------------- 54-400 | 20 × 2 × 1 3/4 | 20 × 2 F 4 J -------------|----------------------------------------------------- 54-406 | 20 × 2.00 -------------|----------------------------------------------------- 54-428 | 20 × 2 -------------|----------------------------------------------------- 54-559 | 26 × 2.00 -------------|----------------------------------------------------- 54-571 | 26 × 1 3/4 × 2 | 26 × 2 × 1 3/4 | 26 × 2 650 × 50 C -------------|----------------------------------------------------- 54-584 | 26 × 2 × 2 1/2 | 26 × 1 1/2 × 2 -------------|----------------------------------------------------- 54-609 | 28 × 2 -------------|----------------------------------------------------- 57-239 | 300 × 55 A -------------|----------------------------------------------------- 57-251 T | 315 × 55 -------------|----------------------------------------------------- 57-305 | 16 × 2.125 | 16 × 2.125 × 2 -------------|----------------------------------------------------- 57-390 | 450 × 55 A -------------|----------------------------------------------------- 57-406 | 20 × 2.125 | 20 × 2.125 × 2 -------------|----------------------------------------------------- 57-507 | 24 × 2.125 | 24 × 2.125 × 2 -------------|----------------------------------------------------- 57-559 | 26 × 2.125 | 26 × 2.125 × 2 -------------|----------------------------------------------------- 62-203 | 12 1/2 × 2 1/4 320 × 57 -------------|----------------------------------------------------- 62-305 | 16 × 2.125 -------------|----------------------------------------------------- 67-203 | 13 × 2 1/2 330 × 65 -------------|----------------------------------------------------- 67-381 | 20 × 2 1/2 -------------|----------------------------------------------------- 

Such older markings can be appended to the ISO 5775 designation in parentheses.

Beaded-edge tyres

Beaded-edge tyres are mounted on hooked-bead rims. They are marked with an overall diameter code and a nominal section-width code, separated by a cross (×). An example for such a marking is

20×1.375

Rims

ISO 5775-2 defines designations for bicycle rims. It distinguishes between

• Straight-side (SS) rims
• Crotchet-type (C) rims
• Hooked-bead (HB) rims

Rims are designated by their nominal rim diameter and their nominal width, separated by a cross (×). Both are measured in millimeters. The rim type codes SS or HB precede the rim designation, whereas code C is appended to the nominal width. Examples: A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ...

SS 400×20, HB 422×25, 620×13C

The nominal width of a rim is the inner width between the straight sides or beads as one can easily measure it with a caliper (see the standard for drawings and exact measurement procedures).

The standard widths of straight-side rims are:

18, 20, 22, 24, 27, 30.5

The standard widths of crotchet-type rims are:

13C, 15C, 16C, 17C, 19C, 21C, 23C, 25C

The standard widths of hooked-bead rims are:

20, 25, 27

The standard diameters of straight-side and crotchet-type rims are:

194, 203, 222, 239, 248, 251, 279, 288, 298, 305, 317, 330, 337, 340, 349, 355, 357, 369, 381, 387, 390, 400, 406, 419, 428, 432, 438, 440, 451, 484, 489, 490, 498, 501, 507, 520, 531, 534, 540, 541, 547, 559, 565, 571, 584, 590, 597, 609, 622, 630, 635, 642

The standard diameters of hooked-bead rims are:

270, 321, 372, 422, 459, 473, 510, 524, 560, 575, 611

External links

• Tire Sizing (http://www.sheldonbrown.com/tire-sizing.html) by Sheldon Brown

References

• International Standard ISO 5775-1:1997, Bicycle tyres and rims — Part 1: Tyre designations and dimensions

• International Standard ISO 5775-2:1996, Bicycle tyres and rims — Part 2: Rims