I have a small Japanese (Nippon) fold-up bike and I need new tyres and tubes (road/commuting). The wheels are about 12" diameter*. Where would I find replacements please (preferably by web/post), London.

  • I'm not entirely sure how to measure them, the outside diameter is 13 and a quarter inches; the rim diameter is 10.5 inches. Tyre width is 1 and a quarter inch.

(It also says "1.4 x 1.50"; "Ornate" and a max pressure in pascals on the side of the tyre). Picture: https://i.sstatic.net/cbobd.jpg Some parallax

  • 2
    Are you sure that's not 14x1.5? Here's a list of tyre sizes: sheldonbrown.com/tire-sizing.html that might help. Tyre sizing is weird. Hunt for a number like 38-254 on the tyre. Sizes in this format are the only way standards match up.
    – Chris H
    Jun 7, 2017 at 19:25
  • Or 1.4x10.5 ? Which seems plausible to me.
    – Carel
    Jun 7, 2017 at 19:27
  • The picture shows that the rim diameter is around 25cm. The only listed size close to that is 254mm which just happens to be "14 inch". I have no idea where to buy those. And seriously, use the millimeter sizes, inches will only confuse you.
    – ojs
    Jun 7, 2017 at 19:58
  • Ah, yes it says 14 x 1.50 (it's dark here!). I found some more markings. This is (I think) everything: 14.x 1.50 H.578 ORNATE Inflate to x PSI/kPa NYLON 0003 5 then four rifle cross-hair symbols.
    – BobSter
    Jun 7, 2017 at 20:03
  • 2
    If you look closely you should also see "xx-254" on the side of the tire, where xx is likely 38 or something close to that. Jun 7, 2017 at 22:24

2 Answers 2


Tire/Rim sizes can be quite confusing. Often times, in American sizing , a wheel listed as a 12-1/2 for example is actually quite smaller than that. The 12-1/2 actually is a rough measurement of about how big it will be with a tire and the wheel is actually only about 8 inches. Another example would be a 24" rim.. which generally have an ISO/bead seat diameter of 507mm, which when converted to inches is actually only 19.96" not 24" as they are listed.

So to correctly find what tire you need, you will need to first find out the Bead seat diameter of the wheel. The easiest solution may to be to take it to a bike shop and have them look at it.

Otherwise it may be helpful to read through these two Sheldon Brown pages, which fully explain how to find the ISO and what exactly it means.

Image from SheldonBrown.com

More from Sheldon:

Rim Sizing

Tire Sizing

Reading through those links will tell you how to determine the BSD of the wheel and in turn tell you what size tire you need. It may be a Japanese or European size that i am not overly familiar with so i don't want to guess on your behalf, just thought it may help to provide some resources and data.

You should look for a number in a format XX-254 on the tire, where the XX would be the width in millimeters and the 254 is the ISO diameter in mm, for example 50-254 would a 14" tire that is approximately 2" wide.

If i were to guess though it will be a 14" tire, if it is a 14 x 1.5 it should have a marking of 38-254 somewhere. They have a ISO of 254mm which translates to 10" which looks to be about the size of the wheel in the image. Purely a guess though, i would take further measurements to be sure.

  • thanks. Sorry it actually says 14 x 1.50 There is a marking H.578, but no 38-254. I found some more markings (in my answer above) but none seem definitive. I would have to dismantle it to get the circumference etc. Maybe tomorrow.
    – BobSter
    Jun 7, 2017 at 20:10
  • i bet it's a 14 x 1.50 , which may prove quite difficult to find. I found one listing but it is for Razor Scooters on a random webpage, didn't look to see where they were based. monsterscooterparts.com/144ti.html
    – Nate W
    Jun 7, 2017 at 23:10
  • Another listing on amazon, im sure these are all US based though, amazon.com/Kenda-14X1-75-Tire-Bicycle-Street/dp/B00MCX4VXU might check to see if chainreactioncycles.com has them as well
    – Nate W
    Jun 7, 2017 at 23:12
  • 1
    14x1.75 seems quite a bit more common (even halfords sell them) than 14x1.5 and might fit (the rims should be fine but it depends whether there's room for the rubber) 14x2.0 are also sold. Make sure you get decimal not fractional inches as 14 x 1 3/8 and14 x 1 5/8 are also sold and won't fit (298mm BSD, not even on Sheldon's list!)
    – Chris H
    Jun 8, 2017 at 8:56

I was going to ask about the 1 3/8 widths. So, a no-go then. I called one shop in London today who only had 12" or 16" and wanted me to buy (either) one of them because "tyres are made of rubber and stretch". I guess this one looks hopeful and is in the UK

  • 1
    That doesn't sound like any bike shop that has a chance of staying in business -- run a mile from them
    – Chris H
    Jun 8, 2017 at 12:52
  • 1
    Yeah... don't go there lol
    – Nate W
    Jun 8, 2017 at 14:54
  • @bobster - It looks like you've managed to create a second SE username somehow.
    – Criggie
    Jun 9, 2017 at 21:39

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