Bicycle Tyre Size Markings

Bicycle Tyre 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″ 700x35c
28 x 1 5/8 x 1 3/8″
Outer diameter – Approx. 28″ Approx. 700mm
Inner diameter 622 mm – –
Tire section width Approx. 37mm Approx. 1.40″ Approx. 35 mm
Approx. 1 3/8″
Tire section height – Approx. 1 5/8″ –

How many tire sizes are there?

It’s more than 154 by this list alone, which is already a bit short / out of date with the advent of Fat Bikes there’s even more not on here, discounting those omitted by obsolescence and forgotten and most newer larger tyre sizes for BMX.

 

ETRTO ETRTO Width ETRTO Bead Ø Inch French Effective Radius (inc. Tyre) Effective Radius Axle to Inside top of Fork Arch (+6mm) Min. Max. Sizes
7″ 47-93 47 93 7 x 1 3/4 93.5 99.5 99.5mm
8″ 47-94 47 94 20 x 47-50 8 x 2 94 100
50-94 50 94 200 x 50 97 103
54-110 54 110 8 x 2 1/8 8 1/2 x 2 109 115
32-137 32 137 8 x 1 1/4 100.5 106.5
10″ 54-152 44-194 10 x 2 10 x 1 5/8 0 6
11″ 47-222 47 222 11 x 13/4 158 164
12″ 47-203 47 203 12 1/2 x 1.75 12 1/2 x 1.90 148.5 154.5
54-203 54 203 12 x 1.95 155.5 161.5
57-203 57 203 12 1/2 x 2 1/4 R 158.5 164.5
62-203 62 203 12 1/2 x 2 1/4 163.5 169.5
32-239 32 239 12 1/2 x 1 3/8 x 1 1/4 300 x 32A 151.5 157.5
57-239 57 239 12 1/2 x 2 1/4 300 x 55A 176.5 182.5
14″ 57-251 57 251 14 1/2 x 2 1/4 300 x 55A 182.5 188.5
47-254 47 254 14 x 1.75 14 x 1.90 174 180
40-279 40 279 14 x 11/2 350 x 38B 179.5 185.5
37-288 37 288 14 x 1 5/8 x 1 3/8 350A Confort 350A Ballon 350A 1/2Ballon 350 x 32A 181 187
40-288 40 288 14 x 1 5/8 350 x 38A 184 190
44-288 44 288 14 x 1 5/8 x 1 3/8 350A 350 x 42A 188 194
32-298 32 298 14 x 1 1/4 350A 350 x 32A 181 187
16″ 40-305 40 305 16 x 1.50 192.5 198.5
47-305 47 305 16 x 1.75 16 x 1.90 199.5 205.5
54-305 54 305 16 x 1.95 16 x 2.00 206.5 212.5
57-305 57 305 16 x 2.125 209.5 215.5
40-330 40 330 16 x 1 1/2 400 x 38B 205 211
28-340 28 340 400 x 30A 198 204
32-340 32 340 16 x 1 3/8 x 1 1/4 400A 400 x 32A 202 208
37-340 37 340 16 x 1 3/8 x 1 1/4 400 x 35A 400A Confort 400A Ballon 400A 1/2 Ballon 207 213
44-340 44 340 16 x 1 5/8 214 220
28-349 28 349 16 x 11/8 202.5 208.5
32-349 32 349 16 x 11/4 NL 206.5 212.5
37-349 37 349 16 x 1 3/8 211.5 217.5
17″ 32-357 32 357 17 x 1 1/4 210.5 216.5
37-369 37 369 17 x 1 1/4 221.5 227.5
18″ 28-355 28 355 18 x 1 1/8 205.5 211.5
40-355 40 355 18 x 1.50 217.5 223.5
47-355 47 355 18 x 1.75 18 x 1.90 224.5 230.5
37-387 37 387 18 x 1 3/8 230.5 236.5
40-387 40 387 18 x 1 1/2 233.5 239.5
28-390 28 390 18 x 1 1/8 450 x 28A 450A 223 229
37-390 37 390 18 x 1 3/8 450 x 35A 450A 450A Confort 450A Ballon 450A 1/2Ballon 232 238
55-390 55 390 450 x 55A 250 256
57-390 57 390 450 x 55A 450A 252 258
37-400 37 400 18 x 1 3/8 237 243
20″ 54-400 54 400 20 x 2 x 1 3/4 20 x 2F4J 254 260
28-406 28 406 20 x 1 1/8 231 237
32-406 32 406 20 x 1.25 235 241
35-406 35 406 20 x 1.35 238 244
37-406 37 406 20 x 1 3/8 240 246
40-406 40 406 20 x 1.50 243 249
44-406 44 406 20 x 1.625 247 253
47-406 47 406 20 x 1.75 20 x 1.90 250 256
50-406 50 406 20 x 2.00 253 259
54-406 54 406 20 x 2.00 257 263
57-406 57 406 20 x 2.125 260 266 266mm
54-428 54 428 20 x 2.00 268 274
40-432 40 432 20 x 1 1/2 256 262
37-438 37 438 20 x 1 3/8 500A 256 262
40-438 40 438 20 x 1 3/8 500 x 38A 259 265
28-440 28 440 500 x 28A 500A 500A Standard 248 254
40-440 40 440 20 x 1 1/2NL 500 x 38A 260 266
28-451 28 451 20 x 1 1/8 253.5 259.5
37-451 37 451 20 x 1 3/8 B.S. 262.5 268.5 268.5mm
22″ 44-484 44 484 22 x 15/8 x 11/2 286 292
25-489 25 489 22 x 1.00 269.5 275.5
37-489 37 489 22 x 1 3/8 NL 281.5 287.5
40-489 40 489 22 x 1 3/8 x 1 1/2 284.5 290.5
50-489 50 489 22 x 2.00 294.5 300.5
28-490 28 490 550 x 28A 550A 550A Standard 273 279
32-490 32 490 22 x 1 3/8 x 1 1/4 550 x 32A 550A 277 283
37-490 37 490 22 x 13/8 550 x 35A 550A Confort 550A Ballon 550A 1/2 Ballon 282 288
37-498 37 498 22 x 1 3/8 x 1 1/4 286 292
32-501 32 501 22 x 1 1/4 282.5 288.5
37-501 37 501 22 x 1 3/8 287.5 293.5
24″ 40-507 40 507 24 x 1.50 293.5 299.5
44-507 44 507 24 x 1.625 24 x 1.75 297.5 303.5
47-507 47 507 24 x 1.75 24 x 1.85/1.90 300.5 306.5
49-507 49 507 24 x 1.85 302.5 308.5
50-507 50 507 24 x 1.90/2.00 24 x 2.00 24 x 2.125 303.5 309.5
54-507 54 507 24 x 2.10 307.5 313.5
57-507 57 507 24 x 2.125 24 x 2.00 310.5 316.5
60-507 60 507 24 x 2.35 313.5 319.5
44-531 44 531 24 x 1 5/8 x 1 1/2 309.5 315.5
40-534 40 534 24 x 1 1/2 307 313
25-540 25 540 24 x 1.00 295 301
32-540 32 540 24 x 1 3/8 x 1 1/4 24 x 1 3/8 302 308
37-540 37 540 24 x 1 3/8 307 313
40-540 40 540 24 x 1 3/8 x 1 1/2 310 316
22-541 22 541 292.5 298.5
25-541 25 541 600 x 25A 295.5 301.5
28-541 28 541 600 x 28A 600A 600A Standard 298.5 304.5
32-541 32 541 24 x 1 3/8 x 1 1/4 N4 600 x 32A 302.5 308.5
37-541 37 541 600 x 35A 600A Confort 600A Ballon 600A 1/2 Ballon 307.5 313.5
26″ 25-559 25 559 26 x 1.00 304.5 310.5
35-559 35 559 26 x 1.35 314.5 320.5
37-559 37 559 26 x 1 5/8 x 1 3/8 26 x 1.40 316.5 322.5
40-559 40 559 26 x 1.50 319.5 325.5
44-559 44 559 26 x 1.625 26 x 1.50/1.75 323.5 329.5
47-559 47 559 26 x 1.75 26 x 1.85/1.90 326.5 332.5
50-559 50 559 26 x 1.90 26 x 1.95 26 x 1.90/2.00 26 x 2.00/2.10 329.5 335.5
54-559 54 559 26 x 1.95 26 x 2.10 26 x 2.125 333.5 339.5
57-559 57 559 26 x 2.125 26 x 2.20/2.25 336.5 342.5
60-559 60 559 26 x 2.35 339.5 345.5
62-559 62 559 26 x 2.50 341.5 347.5
20-571 20 571 26 x 3/4 650 x 20C 305.5 311.5
23-571 23 571 26 x 7/8 650 x 22C 308.5 314.5
40-571 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 325.5 331.5
47-571 47 571 26 x 1 3/4 650 CS confort 650 x 45C 332.5 338.5
54-571 54 571 26 x 2 x 1 3/4 650 x 50C 339.5 345.5
28-584 28 584 26 x 1 1/8 x 1 1/2 650 x 28B 320 326
32-584 32 584 650 x 32B 324 330
35-584 35 584 26 x 1 3/8 x 1 1/2 650 x 35B 650B Standard 327 333
37-584 37 584 26 x 1 1/2 x 1 3/8 26 x 1 1/2 650 x 35B 329 335
40-584 40 584 26 x 1 5/8 x 1 1/2 650 x 42B 650B Semi-Confort 650B 1/2 Ballon 332 338
20-590 20 590 650 x 20A 315 321
25-590 25 590 26 x 1 1/8, 1 1/4 26 x 1 3/8 – 1 1/4 650 x 32A 320 326
28-590 28 590 26 x 1 1/8 650 x 28A 323 329
32-590 32 590 26 x 1 1/4 26 x 1 3/8 x1 1/4 650 x 32A 327 333
35-590 35 590 26 x 1 3/8 650 x 35A 330 336
37-590 37 590 26 x 1 3/8 650 x 35A 650A 332 338
40-590 40 590 26 x 1.50 28 x 1 3/8 x 1 1/2 650 x 38A 335 341
44-590 44 590 339 345
32-597 32 597 26 x 1 1/4 330.5 336.5
27″ 40-609 40 609 27 x 1 1/2 344.5 350.5 341
20-630 20 630 27 x 3/4 335 341
22-630 22 630 27 x 7/8 337 343
25-630 25 630 27 x 1.00 27 x 1 1/16 340 346
28-630 28 630 27 x 1 1/8 27 x 1 1/4 Fifty 27 x 1 1/4 343 349
32-630 32 630 27 x 1 1/4 347 353
28/32-630 28 630 27 x 1 1/4 343 349
35-630 35 630 27 x 1 3/8 350 356
28″ 18-622 18 622 28 x 3/4 700 x 18C 329 335 335
19-622 19 622 700 x 19C 330 336
20-622 20 622 28 x 3/4 700 x 20C 331 337
22-622 22 622 28 x 7/8 700 x 22C 333 339
23-622 23 622 28 x 7/8 700 x 23C 334 340
25-622 25 622 28 x 1.00, 1 1/16 700 x 25C 336 342
30-622 30 622 28 x 1.20 700 x 28C 341 347
28-622 28 622 28 x 1 5/8 x 1 1/8 700 x 30C 339 345
32-622 32 622 28 x 15/8 x 11/4 700 x 32C 700C COURSE 343 349
35-622 35 622 28 x 15/8 x 13/8 700 x 35C 346 352
37-622 37 622 28 x 1 5/8 x 1 3/8 700 x 35C 348 354
40-622 40 622 28 x 1.50 28 x 1 5/8 x 1 1/2 700 x 38C 351 357
42-622 42 622 28 x 1.60 700 x 40C 353 359
44-622 44 622 28 x 1.625 700 x 42C 355 361
47-622 47 622 28 x 1.75 700 x 45C 358 364
50-622 50 622 28 x 1.90 28 x 2.00 361 367
60-622 60 622 28 x 2.35 371 377 377
32-635 32 635 28 x 1 1/2 x 1 1/8 770 x 28B 700 x 28B 770B COURSE 349.5 355.5
40-635 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 357.5 363.5
44-635 44 635 28 x 15/8 x 11/2 700 x 40/42B 361.5 367.5
28-642 28 642 28 x 1 3/8 x 1 1/8 700 x 28A 349 355
37-642 37 642 28 x 1 3/8 700 x 35A 358 364 377mm