Tube Sizes Demystified !

by Biju K on October 05, 2021

Tubes, Tubes Everywhere, in all sizes, but I'm confuses so much with the jargons! - This is often the case we hear all the time as tubes is used all around the world and people and companies prefer to call them and denote them in their own language and terminologies! - Here's a guide to understand them better and in detail! 🥸


 

What do the various size specifications on bicycle tires mean?

Nowadays, bicycle tire sizes are all marked according to ETRTO (European Tire and Rim Technical Organization) 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 a precise classification of the rim size.

The inch marking (e.g. 28 x 1.40) states the approximate outer diameter (28 inches) and the tire width (1.40 inches). Another inch marking is 28 x 1 5/8 x 1 3/8 (approximate outer diameter x tire height x tire width); it 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. But only in decimal form, 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 622 mm, known as 28 inch in Europe.

The latest tire size is 27.5 inches. This tire size is favored for MTBs which are too small for the very big 29 inch wheels, in order to benefit from the advantages of bigger diameters. This is the case, for example, with bicycles having a very long suspension travel or very small frame sizes. 27.5 inch tires have an inner diameter of 584 mm and are identical with the old French size marking 650B.

French size markings (e.g. 700 x 35C) give the approximate tire outer diameter (700 mm) and width (35 mm). 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. 


  ETRTO Inches French
Size marking 37-622

28 x 1.40

28 x 1 5⁄8 x 1 3⁄8

700 x 35C
Outer diameter - ca. 28 inch ca. 700 mm
Inner diameter 622 mm - -
Tire width ca. 37 mm

ca. 1 3⁄8 inch

bzw. 1.40 inch

ca. 35 mm
Tire height -

ca. 1 5⁄8 inch

-

How many tire sizes are there?

The following list shows all common tire sizes. For virtually every tire size, you should be able to find a corresponding ETRTO-size in this list.

The current Schwalbe sizes and markings are given in bold. We have tried to list in addition all tire sizes which are currently used on the market or which were used in the past. These classical fractional size indications are also often engraved on old Schwalbe tires. Sometimes, you still find them on current models which have already been available for quite a long time.


  ETRTO Inch French

12"

47-203 12 x 1.75  
    12 x 1.90  
    12 ½ x 1.75  
    12 ½ x 1.90  
  50-203 12 x 2.00  
  54-203 12 x 1.95  
  57-203 12 ½ x 2 ¼  
  62-203 12 ½ x 2 ¼  

14"

47-254 14 x 1.75  
    14 x 1.90  
  50-254 14 x 2.00  
  40-279 14 x 1 ½ 350 x 38B
  37-288

14 x 1 38

350 x 35A
   

14 x 1 58 x 1 38

 
  40-288

14 x 1 58

350 x 38A
  44-288

14 x 1 58 x 1 38

350 x 42A
  47-288 14 x 1.75  
  32-298 14 x 1 ¼ 350 x 32A

16"

40-305 16 x 1.50  
  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 ½ 400 x 38B
  28-340   400 x 30A
  32-340

16 x 1 38 x 1 14

400 x 32A
  37-340

16 x 1 38

400 x 35A
  44-340

16 x 1 58

 
  28-349

16 x 1 18

 
  30-349 16 x 1.20  
  32-349 16 x 1 ¼  

 

  16 x 1.25  
  35-349 16 x 1.35  
  37-349

16 x 1 38

 

17"

32-357 17 x 1 ¼  
  32-369 17 x 1 ¼  

18"

28-355

18 x 1 18

 
  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 ½  
  28-390

18 x 1 18

450 x 28A
  37-390

18 x 1 38

450 x 35A
  55-390   450 x 55A
  57-390   450 x 55A
  37-400

18 x 1 38

 

20"

54-400 20 x 2 x 1 ¾  
  23-406 20 x 0.90  
  25-406 20 x 1.00  
  28-406 20 x 1.10  
   

20 x 1 18

 
  32-406 20 x 1.25  
  35-406 20 x 1.35  
  37-406 20 x 1.40  
   

20 x 1 38

 
  40-406 20 x 1.50  
  42-406 20 x 1.60  
  44-406 20 x 1.50  
  44-406 20 x 1.625  
  47-406 20 x 1.75  
  47-406 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 ½  
  37-438

20 x 1 38

 
  40-438

20 x 1 38 x 1 ½

 
  28-440   500 x 28A
  37-440   500 x 35A
  40-440 20 x 1 ½ NL 500 x 38A
  23-451 20 x 0.90  
   

20 x 78

 
  25-451 20 x 1.00  
  28-451

20 x 1 18

 
  37-451

20 x 1 38 B.S.

 

22"

44-457 22 x 1.75  
  44-484

22 x 1 58 x 1 ½

 
  25-489 22 x 1.00  
  37-489

22 x 1 3⁄8 NL

 
  40-489

22 x 1 38 x 1 ½

 
  50-489 22 x 2.00  
  28-490   550 x 28A
  32-490

22 x 1 38 x 1 14

550 x 32A
  37-490

22 x 1 38

550 x 35A
  47-498

22 x 1 38 x 1 14

 
  25-501 22 x 1.00 B.S.  
  32-501 22 x 1 ¼  
  37-501

22 x 1 38

 

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  
    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 78

 
  44-531

24 x 1 58 x 1 12

 
  40-534 24 x 1 ½  
  20-540 24 x ¾  
  23-540 24 x 0.90  
   

24 x 78

 
  25-540 24 x 1.00  
  30-540 24 x 1.20  
  32-540

24 x 1 38 x 1 14

 
  37-540

24 x 1 38

 
  40-540

24 x 1 38 x 1 12

 
  22-541    
  25-541   600 x 25A
  28-541   600 x 28A
  32-541

24 x 1 38 x 1 14 NL

600 x 32A
  37-541   600 x 35A


  ETRTO Inch French

25"

57-520 25 x 2.25  

26"

20-559

26 x 34

 
  23-559 26 x 0.90  
   

26 x 78

 
  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 58 x 1 38

 
  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  
  50-559 26 x 2.00  
    26 x 1.90  
    26 x 1.95  
  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  
  60-559 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 34

 
  23-571

26 x 78

650 x 23C
  40-571 26 x 1 ½ CS 650 x 38C
   

26 x 1 38 x 1 12 NL

 
  47-571 26 x 1 ¾ 650 x 45C
      650 CS Confort
  54-571 26 x 2 x 1 ¾ 650 x 50C
  20-590 26 x ¾ 650 x 20A
  25-590 26 x 1.00 650 x 25A
  28-590

26 x 1 38 x 1 18

650 x 28A
  32-590

26 x 1 38 x 1 ¼

650 x 32A
  37-590

26 x 1 38

650 x 35A
  40-590 26 x 1.50 650 x 38A
   

26 x 1 38 x 1 ½

 
  42-590

26 x 1 58

650 x 40A
  32-597

26 x 1 14

 

27"

40-609 27 x 1 ½  
  20-630 27 x ¾  
  22-630

27 x 78

 
  25-630 27 x 1.00  
   

27 x 1 116

 
  28-630

27 x 1 18

 
  32-630 27 x 1 ¼  
  35-630

27 x 1 38

 

27.5"

28-584

26 x 1 18 x 1 12

650 x 28B
  32-584   650 x 32B
  35-584 27.5 x 1.35 650B
   

26 x 1 38 x 1 12

650 x 35B
  37-584 27.5 x 1.40 650B
   

26 x 1 12 x 1 38

650 x 35B
     

650 Standard

  40-584 27.5 x 1.50 650B
   

26 x 1 58 x 1 12

650 x 38B
  44-584 27.5 x 1.65 650B
   

26 x 1 58 x 1 22

650 x 42B
     

650B

Semi-Confort

      650B ½ Ballon
  47-584 27.5 x 1.75 650B
  50-584 27.5 x 2.00 650B
  54-584 27.5 x 2.10 650B
    26 x 1 ½ x 2  
  57-584 27.5 x 2.25 650B

 

60-584 27.5 x 2.35 650B
  62-584 27.5 x 2.40 650B
  64-584 27.5 x 2.50 650B
  65-584 27.5 x 2.60 650B
  70-584 27.5 x 2.75 650B
  74-584 27.5 x 2.90 650B
  75-584 27.5 x 3.00 650B

28"

18-622 28 x ¾ 700 x 18C
  19-622   700 x 19C
      700 x 19
  20-622 28 x ¾ 700 x 20C
  22-622

28 x 78

700 x 22C
      700 x 22
  23-622 28 x 0.90 700 x 23C
   

28 x 78

 
  24-622   700 x 24C
  25-622 28 x 1.00 700 x 25C
   

28 x 1 116

 
  26-622   700 x 26C
  28-622 28 x 1.10 700 x 28C
   

28 x 1 58 x 1 18

 
  30-622 28 x 1.20 700 x 30C
  32-622 28 x 1.25 700 x 32C
   

28 x 1 58 x 1 ¼

 
  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 58 x 1 38

 
  40-622 28 x 1.50 700 x 38C
   

28 x 1 58 x 1 ½

 
  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 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 ½ x 1 18

770 x 28B
      700 x 28B
      700B Course
  40-635 28 x 1 ½ 700 x 38B
   

28 x 1 ½ x 1 58

700B Standard

  44-635

28 x 1 58 x 1 ½

700 x 42B
  28-642

28 x 1 58 x 1 ½

700 x 28A
  37-642

28 x 1 38

700 x 35A

29"

50-622 29 x 2.00  
    28 x 2.00  
  54-622 29 x 2.10  
    28 x 2.10  
  55-622 29 x 2.15  
    28 x 2.15  
  57-622 29 x 2.25  
  60-622 29 x 2.35  
    28 x 2.35  
  75-622 29 x 3.00  

Note: 28 inch and 29 inch tires have the same inner diameter of 622 mm and can be fitted on the same rims.


Example of Classification Of Schwalbe Tubes on Execution / Application Type

What is actually the difference between 28 and 29 inches?

The silliest answer to this question would be to say that the difference is exactly 1 inch. Another answer would be: There is no difference.



Both tire sizes have the same inner diameter of 622 mm and can therefore be fitted on the same rims.

In Europe, 28 inches is a traditional size for touring bicycles. In many countries it is even the most frequent tire size used. In countries outside Europe the rim diameter of 622 mm is only rarely used. Bicycle travelers who want to buy spare tires for a 28-inch touring bicycle anywhere in the world, can tell you a thing or two about it.

A few years ago 29 inch tires were introduced as a new wheel size for mountain bikes in the US. The marking was created, as the MTB tires are more voluminous and the outer diameter measures approximately 29 inches.

Both indications are, however, very imprecise. A less wide 28 inch tire, e.g. with a tire width of 23 mm, which is usual for a road bike, has in fact only an outer diameter of something more like 26 inches. In the case of a tire width of 40 mm,
it is more or less correct that the outer diameter measures 28 inches. In the case of very wide tires with 60 mm or more, the actual outer diameter measures almost 30 inches.


What are the advantages of the new wheel sizes 27.5 and 29 inches?

The new sizes are well established on the market and this is for good reason. The advantages of the large wheels outweigh the disadvantages. 29 inch wheels weigh a little more, are less manoeuvrable and possibly less stiff, but they roll clearly faster on rough surfaces especially in the terrain. The contact surface is bigger which makes for a significantly better tire grip.



There are, however, some bicycles which do not have enough clearance for a large 29 inch wheel, e.g. in the case of very small frame sizes and in particular bicycles with very long suspension travel. This is where the new wheel size 27.5 comes in.

Schwalbe will continue to offer all usual MTB tires for all three diameters.


Now let's dig up little into the Valves...

Which is the best valve?



There are three types that have become market standards and it is difficult to make any particular recommendation. The most important aspect is that the valve fits the rim valve hole and that an appropriate pump is available. Contrary to popular belief, major air retention differences are now a thing of the past. In any case, all Schwalbe valves provide excellent performance and are adapted to high-pressure use.



The classical bicycle valve or Dunlop valve is still the most common worldwide. Most cyclists are familiar with it. The valve core can easily be replaced and air can be released very quickly. Fitting a tube with a Dunlop valve is more awkward, as the valve core and locknut need to be removed in order to fit the valve through the valve hole. Inflation is only possible once the core and the nut are back in place.

With traditional Dunlop valves, it is impossible to check the inflation pressure. However, the special Schwalbe Dunlop valve allows a return airflow, so that it is now possible to check the inflation pressure with an Airmax pressure gauge.

Formerly it was difficult to inflate a tube with a Dunlop valve, but with today´s modern valve cores, this is no longer the case.

The Sclaverand valve is narrower than other valves (6 instead of 8 mm). It needs a smaller rim hole and is therefore particularly well suited for narrow racing bike rims. It is also approx. 4-5 g lighter than a car valve or Dunlop valve.

It can be locked manually with the knurled nut. Before inflating, the knurled nut must be loosened. First time users frequently have some problems. Also the thin top pin can be easily bent when attaching and removing the pump connector.

Caution: Be aware that using Sclaverand valve tubes on rims with larger valve holes often leads to a valve tear off when the sharp metal edges around the valve hole cut the valve stem off the tube.

The Auto/Car valve can be inflated very easily at a filling station and is pleasantly unproblematic. Older, as well as simple bicycle pumps are not compatible with car valves.


What is the purpose of a rim nut?



The rim nut fixes the valve in the rim. Some regard it as unnecessary. And indeed, you may well ride your bicycle without a rim nut. It is however helpful when attaching the pump connector, as particularly when the pressure is low the valve may fall inside the rim. With some rims there may be a rattle if the valve is not fixed.

The rim nut must only be tightened by hand. Never tighten the rim nut with pliers, as this can lead to tube damage.

What causes a valve tear off?


A valve tear off can occur if it was installed under tension.

Another frequent cause is installing a Sclaverand valve tube into a rim with a larger valve hole. The metal edge of the valve hole can shear the valve stem off the tube.

Caution: Be aware that there are also rims that have the correct valve hole of 6.5 mm on the outside, but a larger hole of 8.5 mm on the inside, which causes the problem. A nut that is excessively tightened just exacerbates the problem of tear off. The major role of the rim nut is to lock the valve in place at the time of inflation.

In most cases valve tear off is due to tire slip. Continual improvement in brake performance and low inflation pressures often cause the tire to slip on the rim. The tire movement then drags the tube and this can lead to the valve shearing off.

What can be done to prevent tire slip or valve tear off?



Schwalbe tire with L.S.T. coating on the bead

A higher inflation pressure considerably reduces the tire slip. Of course a higher tire pressure is not always desired.

We implement Limited Slip Technology (LST) in Schwalbe MTB-folding and balloon tires. The tire bead is coated with a special rubber layer that produces a dramatic reduction in tire/rim slip.

The Schwalbe Downhill tube has a highly reinforced valve foot.

Theoretically, the use of talcum powder is also helpful. This can reduce the friction between tire and tube. However in practice, if talcum powder gets between tire and rim, it will increase the problem.

Some rims have such slippery surfaces that even LST does not suffice one hundred percent. It will help if the rim contact area with the tire is lightly abraded with sandpaper (180 grade). This considerably increases the friction between tire and rim.

The problem is very much reduced with disc brakes because the rims do not get hot through braking.

There is no valve tear off with tubeless tires. The tire can move without causing problems.

Courtesy: Schwalbe Germany, our channel partners for tires & tubes solutions. 

1 comment
by Adarsh Kumar on March 11, 2022

Really helped me out A LOT. Thanks for helping us, cyclists understand these and continue the good work :)

LEAVE A COMMENT

Please note, comments must be approved before they are published


Promo box

Someone purchsed a

Product name

info info