Cycling UK Forum

I used to reckon my motorbike did approximately 10 miles per litre, back when I had a motorbike. Never bothered to calculate it accurately.

Why not have both metric and imperial in the same discussion, just to confuse people:
From the GWR cycling leaflet https://www.gwr.com/-/media/gwr-sc-webs ... -train.pdf:

When making a reservation, please be aware
we can only guarantee your bike will fit if it
has a tyre width of 7cm or less and a rim
diameter of 50cm or less.
Folding bikes with a maximum 20-inch
wheel can be taken on any train at any time.
Please fold the bike before boarding

(never mind about the fact that no adult bike fits the 50cm limit, that's for another thread

Well, bike wheels are dimensioned in mm but described in inches! 20" is an unfortunate example for them to choose as there are two main standards - the BMX 406mm and the older British 451mm. These are bead seat diameters and neither of them tell you anything about the tyre diameter, which is probably what matters on public transport.

The most stupid thing in bike tyre sizing is that the Europeans call 700c 28" (yes, really) although a typical 700c tyre is quite a bit less than 27" in diameter, let alone 28". Mnd you, 700c is itself stupid - the rim size is 622mm and the "700" refers to a rather fat tyre that was used on this size rim about a century ago.

rogerzilla wrote: ↑23 Apr 2024, 7:23am Well, bike wheels are dimensioned in mm but described in inches! 20" is an unfortunate example for them to choose as there are two main standards - the BMX 406mm and the older British 451mm. These are bead seat diameters and neither of them tell you anything about the tyre diameter, which is probably what matters on public transport.

The most stupid thing in bike tyre sizing is that the Europeans call 700c 28" (yes, really) although a typical 700c tyre is quite a bit less than 27" in diameter, let alone 28". Mnd you, 700c is itself stupid - the rim size is 622mm and the "700" refers to a rather fat tyre that was used on this size rim about a century ago.

wodevva ... that 50cm figure in the GWR info is clearly a mistake!

All of that. ETRO ftw, or ISO as it is now (easier to say than "ETRTO" as well).

rogerzilla wrote: ↑23 Apr 2024, 7:23am Well, bike wheels are dimensioned in mm but described in inches! 20" is an unfortunate example for them to choose as there are two main standards - the BMX 406mm and the older British 451mm. These are bead seat diameters and neither of them tell you anything about the tyre diameter, which is probably what matters on public transport.

The most stupid thing in bike tyre sizing is that the Europeans call 700c 28" (yes, really) although a typical 700c tyre is quite a bit less than 27" in diameter, let alone 28". Mnd you, 700c is itself stupid - the rim size is 622mm and the "700" refers to a rather fat tyre that was used on this size rim about a century ago.

Bmblbzzz wrote: ↑23 Apr 2024, 9:43am All of that. ETRO ftw, or ISO as it is now (easier to say than "ETRTO" as well).

Yes, the traditional sizing systems are fascinating and of great historical interest. And that's precisely where they should now be confined.

This forum looks like a good place to promote use of ISO sizing.

Jonathan

https://en.wikipedia.org/wiki/ISO_5775
https://sheldonbrown.com/tire-sizing.html

Bmblbzzz wrote: ↑23 Apr 2024, 9:43am All of that. ETRO ftw, or ISO as it is now (easier to say than "ETRTO" as well).

Although most people say it incorrectly - it's Iso from the Greek Isos - equitable. (It's not an abbreviation as the organisation name is International Organisation for Standardisation)

st599_uk wrote: ↑23 Apr 2024, 10:54am

Bmblbzzz wrote: ↑23 Apr 2024, 9:43am All of that. ETRO ftw, or ISO as it is now (easier to say than "ETRTO" as well).

Although most people say it incorrectly - it's Iso from the Greek Isos - equitable. (It's not an abbreviation as the organisation name is International Organisation for Standardisation)

It's not an abbreviation, but the organisation writes it all in capitals:
https://www.iso.org/home.html
https://en.wikipedia.org/wiki/Internati ... reviations

How do you think it should be pronounced?

Thanks

Jonathan

I pronounce it in line with the IPA on that Wikipedia page, as has everyone else I've ever heard pronounce it (at least in an English context). I don't know how to pronounce the Greek word.

Jdsk wrote: ↑23 Apr 2024, 10:57am It's not an abbreviation, but the organisation writes it all in capitals:
https://www.iso.org/home.html

Which makes it an acronym - like NASA or laser.
It's pronounced as eye-so (although isos as a Greek word is pronounced ee-soss).

Jdsk wrote: ↑23 Apr 2024, 10:02am Yes, the traditional sizing systems are fascinating and of great historical interest. And that's precisely where they should now be confined.

Problem is that so much of it is standardised across numerous countries and manufacturers and the fact that Americans work in imperial isn't helping either.
Bikes have always been a weird mash-up of imperial and metric largely stemming from their evolution. Europe (with its rich history of road racing) gave road bikes predominantly metric sizing. America, where the MTB originated, meant that much of the early days of MTB was dominated by imperial.
Plus, as already mentioned, lots of the sizes referred to in everyday language isn't actually correct anyway - 700c being the obvious one!

rareposter wrote: ↑23 Apr 2024, 11:51am

Jdsk wrote: ↑23 Apr 2024, 10:02am Yes, the traditional sizing systems are fascinating and of great historical interest. And that's precisely where they should now be confined.

Problem is that so much of it is standardised across numerous countries and manufacturers and the fact that Americans work in imperial isn't helping either.
Bikes have always been a weird mash-up of imperial and metric largely stemming from their evolution. Europe (with its rich history of road racing) gave road bikes predominantly metric sizing. America, where the MTB originated, meant that much of the early days of MTB was dominated by imperial.
Plus, as already mentioned, lots of the sizes referred to in everyday language isn't actually correct anyway - 700c being the obvious one!

Yes, that's part of the history. But we'd do better to look to the future rather than inflict this on another generation.

Jonathan

PS: The USA uses US customary units, not the Imperial system. Along with a lot of metric.
https://en.wikipedia.org/wiki/United_St ... mary_units
https://en.wikipedia.org/wiki/Metricati ... ted_States

I think this is a slightly separate issue. Conventional tyre sizes, such as 700C and 26", are rather more akin to names than measurements. The names sometimes incorporate or refer to what appear to be units, but they do not function as units in this context.

It's a similar situation with clothing, where a "measurement" is in fact more of a comparative scale - but only comparative to other sizes of the same design - rather than corresponding to an actual measurement of the garment (or the body it's meant to fit). Whereas gear inches really are inches, even if only approximated.

st599_uk wrote: ↑23 Apr 2024, 10:54am

Bmblbzzz wrote: ↑23 Apr 2024, 9:43am All of that. ETRO ftw, or ISO as it is now (easier to say than "ETRTO" as well).

Although most people say it incorrectly - it's Iso from the Greek Isos - equitable. (It's not an abbreviation as the organisation name is International Organisation for Standardisation)

Or is it simply an acronym which was a compromise in a similar way to UTC - Universal Coordinated Time. The acronym came about as a compromise between English and French speakers: Coordinated Universal Time would normally be abbreviated as CUT for English speakers, and the French name, Temps Universel Coordonné, would be TUC and so UTC was incorrect in both languages. According to https://www.iso.org/about-us.html#:~:te ... O%E2%80%9D. "Because “International Organization for Standardization” would have different acronyms in different languages (IOS in English, OIN in French for Organisation internationale de normalisation), its founders opted for the short form “ISO”."

Jdsk wrote: ↑23 Apr 2024, 10:57am

st599_uk wrote: ↑23 Apr 2024, 10:54am

Bmblbzzz wrote: ↑23 Apr 2024, 9:43am All of that. ETRO ftw, or ISO as it is now (easier to say than "ETRTO" as well).

Although most people say it incorrectly - it's Iso from the Greek Isos - equitable. (It's not an abbreviation as the organisation name is International Organisation for Standardisation)

It's not an abbreviation, but the organisation writes it all in capitals:
https://www.iso.org/home.html
https://en.wikipedia.org/wiki/Internati ... reviations

How do you think it should be pronounced?

Thanks

Jonathan

The receptionist when you go in pronounces it Ee soh

st599_uk wrote: ↑23 Apr 2024, 4:31pm

Jdsk wrote: ↑23 Apr 2024, 10:57am

st599_uk wrote: ↑23 Apr 2024, 10:54am Although most people say it incorrectly - it's Iso from the Greek Isos - equitable. (It's not an abbreviation as the organisation name is International Organisation for Standardisation)

It's not an abbreviation, but the organisation writes it all in capitals:
https://www.iso.org/home.html
https://en.wikipedia.org/wiki/Internati ... reviations

How do you think it should be pronounced?

The receptionist when you go in pronounces it Ee soh

I most commonly hear eye-soh and after that eye-ess-oh. That's both in common parlance in England and in work on standards in the UK, the EU and the USA.

How do you think it should be pronounced?

Thanks

Jonathan