I am currently having tyre 40-559(ETRTO) or 26"X1.5 and tube picture. But I recently thought of buying a spare tube and tyre(available on some offer). However, I had a hard time in matching it with my current tyre dimensions.

Tube on offer: HUTCHINSON 650x28-42 A/B (26x1"1/4 / 1"3/8)
(ETRTO 28/42 - 571/584)   

And a tyre also on offer:

VTC 37-590 1 26x1-3/8 650x35A HS348

As I am new please forgive me for the obvious or senseless questions. But I didn't seem to get help from the shops or Google search.


1 Answer 1


40-559 is the number to match. For tubes, the ETRTO number is a range of fitting tire sizes. For complete explanation, see http://www.sheldonbrown.com/tire-sizing.html

EDIT: This answer originally hinted that 37-590 would be correct. It isn't, 559 is the rim diameter and it must match.

  • Can I go for 37-590(as it seems)? I have put the tube pic now(in the edit)
    – L.K.
    Commented Mar 19, 2017 at 13:19
  • 1
    @gschenk But if both(559 and 590) are 26 inches but 590 is only little bit wider than the 559, it should be ok, isn't it?
    – L.K.
    Commented Mar 19, 2017 at 17:22
  • 1
    @L.K. - No, it won't fit. See the photo here: bicycles.stackexchange.com/questions/13907/… Commented Mar 19, 2017 at 17:37
  • 3
    @L.K. 26 inches is not a physical measurement, it is there only to confuse people. 590 and 559 are actual rim diameters in millimeters. The Sheldon Brown link explains the historical reasons.
    – ojs
    Commented Mar 19, 2017 at 17:55
  • 1
    @L.K. an ETRTO code has the structure width-diameter. For example, 40-559 means the tire is 40 mm wide and fits on a rim with a diameter of 559 mm.
    – gschenk
    Commented Mar 19, 2017 at 17:56

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