As in title, can I use 26 1 3/8 tire to replace a 27 1 1/4?

Is this workable with some elbow grease? Any negative consequences of trying? It is an older road bike with the original tires (27 1 1/4). I went to a local store and closest match was 26 1 3/8.

  • 3
    I was working on a 27x1 1/4 tire just this afternoon. There's no way any 26" tire can replace it. And you will likely wreck the rim if you try. Aug 7, 2019 at 2:14
  • 1
    And to preempt the next question, you can't use a 622mm tyre (aka a 700c tyre size) on the 630 mm rims you have now. Even though they only differ by 4mm in radius, the bead is simply not going to hook in safely.
    – Criggie
    Aug 7, 2019 at 4:20

1 Answer 1


No. Bicycle tire sizes are a dogs breakfast of standards. The only standard that is consistent is ISO.

According to Sheldon Brown, 27" is ISO630 and 26" (the common sized MTB tire) is ISO 559.

ISO630 (27x1/14) are available with a search on the internet e.g. Sheldon Brown / Harris Cyclery (not a recommendation)

  • 2
    To add to this, there’s some wiggle room on tire width, but none on diameter.
    – Adam Rice
    Aug 7, 2019 at 2:45
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    The are many incompatible 26" sizes, 559 is just the most common
    – ojs
    Aug 7, 2019 at 3:58
  • 2
    More specifically, the 26 x 1 3/8 that was in the store was likely ISO 590 or 597, not the MTB 559, which is the 26” decimal sized tires.In any case, you can get 27x 1 1/4 tires online if the shop can’t get them for you
    – Andrew
    Aug 7, 2019 at 19:19

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